Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/mm/memory.c

  1 /*
  2  *  linux/mm/memory.c
  3  *
  4  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  5  */
  6 
  7 /*
  8  * demand-loading started 01.12.91 - seems it is high on the list of
  9  * things wanted, and it should be easy to implement. - Linus
 10  */
 11 
 12 /*
 13  * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
 14  * pages started 02.12.91, seems to work. - Linus.
 15  *
 16  * Tested sharing by executing about 30 /bin/sh: under the old kernel it
 17  * would have taken more than the 6M I have free, but it worked well as
 18  * far as I could see.
 19  *
 20  * Also corrected some "invalidate()"s - I wasn't doing enough of them.
 21  */
 22 
 23 /*
 24  * Real VM (paging to/from disk) started 18.12.91. Much more work and
 25  * thought has to go into this. Oh, well..
 26  * 19.12.91  -  works, somewhat. Sometimes I get faults, don't know why.
 27  *              Found it. Everything seems to work now.
 28  * 20.12.91  -  Ok, making the swap-device changeable like the root.
 29  */
 30 
 31 /*
 32  * 05.04.94  -  Multi-page memory management added for v1.1.
 33  *              Idea by Alex Bligh (alex@cconcepts.co.uk)
 34  *
 35  * 16.07.99  -  Support of BIGMEM added by Gerhard Wichert, Siemens AG
 36  *              (Gerhard.Wichert@pdb.siemens.de)
 37  *
 38  * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
 39  */
 40 
 41 #include <linux/kernel_stat.h>
 42 #include <linux/mm.h>
 43 #include <linux/hugetlb.h>
 44 #include <linux/mman.h>
 45 #include <linux/swap.h>
 46 #include <linux/highmem.h>
 47 #include <linux/pagemap.h>
 48 #include <linux/ksm.h>
 49 #include <linux/rmap.h>
 50 #include <linux/export.h>
 51 #include <linux/delayacct.h>
 52 #include <linux/init.h>
 53 #include <linux/writeback.h>
 54 #include <linux/memcontrol.h>
 55 #include <linux/mmu_notifier.h>
 56 #include <linux/kallsyms.h>
 57 #include <linux/swapops.h>
 58 #include <linux/elf.h>
 59 #include <linux/gfp.h>
 60 #include <linux/migrate.h>
 61 #include <linux/string.h>
 62 #include <linux/dma-debug.h>
 63 #include <linux/debugfs.h>
 64 
 65 #include <asm/io.h>
 66 #include <asm/pgalloc.h>
 67 #include <asm/uaccess.h>
 68 #include <asm/tlb.h>
 69 #include <asm/tlbflush.h>
 70 #include <asm/pgtable.h>
 71 
 72 #include "internal.h"
 73 
 74 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
 75 #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
 76 #endif
 77 
 78 #ifndef CONFIG_NEED_MULTIPLE_NODES
 79 /* use the per-pgdat data instead for discontigmem - mbligh */
 80 unsigned long max_mapnr;
 81 struct page *mem_map;
 82 
 83 EXPORT_SYMBOL(max_mapnr);
 84 EXPORT_SYMBOL(mem_map);
 85 #endif
 86 
 87 /*
 88  * A number of key systems in x86 including ioremap() rely on the assumption
 89  * that high_memory defines the upper bound on direct map memory, then end
 90  * of ZONE_NORMAL.  Under CONFIG_DISCONTIG this means that max_low_pfn and
 91  * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
 92  * and ZONE_HIGHMEM.
 93  */
 94 void * high_memory;
 95 
 96 EXPORT_SYMBOL(high_memory);
 97 
 98 /*
 99  * Randomize the address space (stacks, mmaps, brk, etc.).
100  *
101  * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
102  *   as ancient (libc5 based) binaries can segfault. )
103  */
104 int randomize_va_space __read_mostly =
105 #ifdef CONFIG_COMPAT_BRK
106                                         1;
107 #else
108                                         2;
109 #endif
110 
111 static int __init disable_randmaps(char *s)
112 {
113         randomize_va_space = 0;
114         return 1;
115 }
116 __setup("norandmaps", disable_randmaps);
117 
118 unsigned long zero_pfn __read_mostly;
119 unsigned long highest_memmap_pfn __read_mostly;
120 
121 EXPORT_SYMBOL(zero_pfn);
122 
123 /*
124  * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
125  */
126 static int __init init_zero_pfn(void)
127 {
128         zero_pfn = page_to_pfn(ZERO_PAGE(0));
129         return 0;
130 }
131 core_initcall(init_zero_pfn);
132 
133 
134 #if defined(SPLIT_RSS_COUNTING)
135 
136 void sync_mm_rss(struct mm_struct *mm)
137 {
138         int i;
139 
140         for (i = 0; i < NR_MM_COUNTERS; i++) {
141                 if (current->rss_stat.count[i]) {
142                         add_mm_counter(mm, i, current->rss_stat.count[i]);
143                         current->rss_stat.count[i] = 0;
144                 }
145         }
146         current->rss_stat.events = 0;
147 }
148 
149 static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
150 {
151         struct task_struct *task = current;
152 
153         if (likely(task->mm == mm))
154                 task->rss_stat.count[member] += val;
155         else
156                 add_mm_counter(mm, member, val);
157 }
158 #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
159 #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
160 
161 /* sync counter once per 64 page faults */
162 #define TASK_RSS_EVENTS_THRESH  (64)
163 static void check_sync_rss_stat(struct task_struct *task)
164 {
165         if (unlikely(task != current))
166                 return;
167         if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
168                 sync_mm_rss(task->mm);
169 }
170 #else /* SPLIT_RSS_COUNTING */
171 
172 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
173 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
174 
175 static void check_sync_rss_stat(struct task_struct *task)
176 {
177 }
178 
179 #endif /* SPLIT_RSS_COUNTING */
180 
181 #ifdef HAVE_GENERIC_MMU_GATHER
182 
183 static int tlb_next_batch(struct mmu_gather *tlb)
184 {
185         struct mmu_gather_batch *batch;
186 
187         batch = tlb->active;
188         if (batch->next) {
189                 tlb->active = batch->next;
190                 return 1;
191         }
192 
193         if (tlb->batch_count == MAX_GATHER_BATCH_COUNT)
194                 return 0;
195 
196         batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
197         if (!batch)
198                 return 0;
199 
200         tlb->batch_count++;
201         batch->next = NULL;
202         batch->nr   = 0;
203         batch->max  = MAX_GATHER_BATCH;
204 
205         tlb->active->next = batch;
206         tlb->active = batch;
207 
208         return 1;
209 }
210 
211 /* tlb_gather_mmu
212  *      Called to initialize an (on-stack) mmu_gather structure for page-table
213  *      tear-down from @mm. The @fullmm argument is used when @mm is without
214  *      users and we're going to destroy the full address space (exit/execve).
215  */
216 void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
217 {
218         tlb->mm = mm;
219 
220         /* Is it from 0 to ~0? */
221         tlb->fullmm     = !(start | (end+1));
222         tlb->need_flush_all = 0;
223         tlb->start      = start;
224         tlb->end        = end;
225         tlb->need_flush = 0;
226         tlb->local.next = NULL;
227         tlb->local.nr   = 0;
228         tlb->local.max  = ARRAY_SIZE(tlb->__pages);
229         tlb->active     = &tlb->local;
230         tlb->batch_count = 0;
231 
232 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
233         tlb->batch = NULL;
234 #endif
235 }
236 
237 static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
238 {
239         tlb->need_flush = 0;
240         tlb_flush(tlb);
241 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
242         tlb_table_flush(tlb);
243 #endif
244 }
245 
246 static void tlb_flush_mmu_free(struct mmu_gather *tlb)
247 {
248         struct mmu_gather_batch *batch;
249 
250         for (batch = &tlb->local; batch; batch = batch->next) {
251                 free_pages_and_swap_cache(batch->pages, batch->nr);
252                 batch->nr = 0;
253         }
254         tlb->active = &tlb->local;
255 }
256 
257 void tlb_flush_mmu(struct mmu_gather *tlb)
258 {
259         if (!tlb->need_flush)
260                 return;
261         tlb_flush_mmu_tlbonly(tlb);
262         tlb_flush_mmu_free(tlb);
263 }
264 
265 /* tlb_finish_mmu
266  *      Called at the end of the shootdown operation to free up any resources
267  *      that were required.
268  */
269 void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
270 {
271         struct mmu_gather_batch *batch, *next;
272 
273         tlb_flush_mmu(tlb);
274 
275         /* keep the page table cache within bounds */
276         check_pgt_cache();
277 
278         for (batch = tlb->local.next; batch; batch = next) {
279                 next = batch->next;
280                 free_pages((unsigned long)batch, 0);
281         }
282         tlb->local.next = NULL;
283 }
284 
285 /* __tlb_remove_page
286  *      Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
287  *      handling the additional races in SMP caused by other CPUs caching valid
288  *      mappings in their TLBs. Returns the number of free page slots left.
289  *      When out of page slots we must call tlb_flush_mmu().
290  */
291 int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
292 {
293         struct mmu_gather_batch *batch;
294 
295         VM_BUG_ON(!tlb->need_flush);
296 
297         batch = tlb->active;
298         batch->pages[batch->nr++] = page;
299         if (batch->nr == batch->max) {
300                 if (!tlb_next_batch(tlb))
301                         return 0;
302                 batch = tlb->active;
303         }
304         VM_BUG_ON_PAGE(batch->nr > batch->max, page);
305 
306         return batch->max - batch->nr;
307 }
308 
309 #endif /* HAVE_GENERIC_MMU_GATHER */
310 
311 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
312 
313 /*
314  * See the comment near struct mmu_table_batch.
315  */
316 
317 static void tlb_remove_table_smp_sync(void *arg)
318 {
319         /* Simply deliver the interrupt */
320 }
321 
322 static void tlb_remove_table_one(void *table)
323 {
324         /*
325          * This isn't an RCU grace period and hence the page-tables cannot be
326          * assumed to be actually RCU-freed.
327          *
328          * It is however sufficient for software page-table walkers that rely on
329          * IRQ disabling. See the comment near struct mmu_table_batch.
330          */
331         smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
332         __tlb_remove_table(table);
333 }
334 
335 static void tlb_remove_table_rcu(struct rcu_head *head)
336 {
337         struct mmu_table_batch *batch;
338         int i;
339 
340         batch = container_of(head, struct mmu_table_batch, rcu);
341 
342         for (i = 0; i < batch->nr; i++)
343                 __tlb_remove_table(batch->tables[i]);
344 
345         free_page((unsigned long)batch);
346 }
347 
348 void tlb_table_flush(struct mmu_gather *tlb)
349 {
350         struct mmu_table_batch **batch = &tlb->batch;
351 
352         if (*batch) {
353                 call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
354                 *batch = NULL;
355         }
356 }
357 
358 void tlb_remove_table(struct mmu_gather *tlb, void *table)
359 {
360         struct mmu_table_batch **batch = &tlb->batch;
361 
362         tlb->need_flush = 1;
363 
364         /*
365          * When there's less then two users of this mm there cannot be a
366          * concurrent page-table walk.
367          */
368         if (atomic_read(&tlb->mm->mm_users) < 2) {
369                 __tlb_remove_table(table);
370                 return;
371         }
372 
373         if (*batch == NULL) {
374                 *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
375                 if (*batch == NULL) {
376                         tlb_remove_table_one(table);
377                         return;
378                 }
379                 (*batch)->nr = 0;
380         }
381         (*batch)->tables[(*batch)->nr++] = table;
382         if ((*batch)->nr == MAX_TABLE_BATCH)
383                 tlb_table_flush(tlb);
384 }
385 
386 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
387 
388 /*
389  * Note: this doesn't free the actual pages themselves. That
390  * has been handled earlier when unmapping all the memory regions.
391  */
392 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
393                            unsigned long addr)
394 {
395         pgtable_t token = pmd_pgtable(*pmd);
396         pmd_clear(pmd);
397         pte_free_tlb(tlb, token, addr);
398         atomic_long_dec(&tlb->mm->nr_ptes);
399 }
400 
401 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
402                                 unsigned long addr, unsigned long end,
403                                 unsigned long floor, unsigned long ceiling)
404 {
405         pmd_t *pmd;
406         unsigned long next;
407         unsigned long start;
408 
409         start = addr;
410         pmd = pmd_offset(pud, addr);
411         do {
412                 next = pmd_addr_end(addr, end);
413                 if (pmd_none_or_clear_bad(pmd))
414                         continue;
415                 free_pte_range(tlb, pmd, addr);
416         } while (pmd++, addr = next, addr != end);
417 
418         start &= PUD_MASK;
419         if (start < floor)
420                 return;
421         if (ceiling) {
422                 ceiling &= PUD_MASK;
423                 if (!ceiling)
424                         return;
425         }
426         if (end - 1 > ceiling - 1)
427                 return;
428 
429         pmd = pmd_offset(pud, start);
430         pud_clear(pud);
431         pmd_free_tlb(tlb, pmd, start);
432 }
433 
434 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
435                                 unsigned long addr, unsigned long end,
436                                 unsigned long floor, unsigned long ceiling)
437 {
438         pud_t *pud;
439         unsigned long next;
440         unsigned long start;
441 
442         start = addr;
443         pud = pud_offset(pgd, addr);
444         do {
445                 next = pud_addr_end(addr, end);
446                 if (pud_none_or_clear_bad(pud))
447                         continue;
448                 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
449         } while (pud++, addr = next, addr != end);
450 
451         start &= PGDIR_MASK;
452         if (start < floor)
453                 return;
454         if (ceiling) {
455                 ceiling &= PGDIR_MASK;
456                 if (!ceiling)
457                         return;
458         }
459         if (end - 1 > ceiling - 1)
460                 return;
461 
462         pud = pud_offset(pgd, start);
463         pgd_clear(pgd);
464         pud_free_tlb(tlb, pud, start);
465 }
466 
467 /*
468  * This function frees user-level page tables of a process.
469  */
470 void free_pgd_range(struct mmu_gather *tlb,
471                         unsigned long addr, unsigned long end,
472                         unsigned long floor, unsigned long ceiling)
473 {
474         pgd_t *pgd;
475         unsigned long next;
476 
477         /*
478          * The next few lines have given us lots of grief...
479          *
480          * Why are we testing PMD* at this top level?  Because often
481          * there will be no work to do at all, and we'd prefer not to
482          * go all the way down to the bottom just to discover that.
483          *
484          * Why all these "- 1"s?  Because 0 represents both the bottom
485          * of the address space and the top of it (using -1 for the
486          * top wouldn't help much: the masks would do the wrong thing).
487          * The rule is that addr 0 and floor 0 refer to the bottom of
488          * the address space, but end 0 and ceiling 0 refer to the top
489          * Comparisons need to use "end - 1" and "ceiling - 1" (though
490          * that end 0 case should be mythical).
491          *
492          * Wherever addr is brought up or ceiling brought down, we must
493          * be careful to reject "the opposite 0" before it confuses the
494          * subsequent tests.  But what about where end is brought down
495          * by PMD_SIZE below? no, end can't go down to 0 there.
496          *
497          * Whereas we round start (addr) and ceiling down, by different
498          * masks at different levels, in order to test whether a table
499          * now has no other vmas using it, so can be freed, we don't
500          * bother to round floor or end up - the tests don't need that.
501          */
502 
503         addr &= PMD_MASK;
504         if (addr < floor) {
505                 addr += PMD_SIZE;
506                 if (!addr)
507                         return;
508         }
509         if (ceiling) {
510                 ceiling &= PMD_MASK;
511                 if (!ceiling)
512                         return;
513         }
514         if (end - 1 > ceiling - 1)
515                 end -= PMD_SIZE;
516         if (addr > end - 1)
517                 return;
518 
519         pgd = pgd_offset(tlb->mm, addr);
520         do {
521                 next = pgd_addr_end(addr, end);
522                 if (pgd_none_or_clear_bad(pgd))
523                         continue;
524                 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
525         } while (pgd++, addr = next, addr != end);
526 }
527 
528 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
529                 unsigned long floor, unsigned long ceiling)
530 {
531         while (vma) {
532                 struct vm_area_struct *next = vma->vm_next;
533                 unsigned long addr = vma->vm_start;
534 
535                 /*
536                  * Hide vma from rmap and truncate_pagecache before freeing
537                  * pgtables
538                  */
539                 unlink_anon_vmas(vma);
540                 unlink_file_vma(vma);
541 
542                 if (is_vm_hugetlb_page(vma)) {
543                         hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
544                                 floor, next? next->vm_start: ceiling);
545                 } else {
546                         /*
547                          * Optimization: gather nearby vmas into one call down
548                          */
549                         while (next && next->vm_start <= vma->vm_end + PMD_SIZE
550                                && !is_vm_hugetlb_page(next)) {
551                                 vma = next;
552                                 next = vma->vm_next;
553                                 unlink_anon_vmas(vma);
554                                 unlink_file_vma(vma);
555                         }
556                         free_pgd_range(tlb, addr, vma->vm_end,
557                                 floor, next? next->vm_start: ceiling);
558                 }
559                 vma = next;
560         }
561 }
562 
563 int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
564                 pmd_t *pmd, unsigned long address)
565 {
566         spinlock_t *ptl;
567         pgtable_t new = pte_alloc_one(mm, address);
568         int wait_split_huge_page;
569         if (!new)
570                 return -ENOMEM;
571 
572         /*
573          * Ensure all pte setup (eg. pte page lock and page clearing) are
574          * visible before the pte is made visible to other CPUs by being
575          * put into page tables.
576          *
577          * The other side of the story is the pointer chasing in the page
578          * table walking code (when walking the page table without locking;
579          * ie. most of the time). Fortunately, these data accesses consist
580          * of a chain of data-dependent loads, meaning most CPUs (alpha
581          * being the notable exception) will already guarantee loads are
582          * seen in-order. See the alpha page table accessors for the
583          * smp_read_barrier_depends() barriers in page table walking code.
584          */
585         smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
586 
587         ptl = pmd_lock(mm, pmd);
588         wait_split_huge_page = 0;
589         if (likely(pmd_none(*pmd))) {   /* Has another populated it ? */
590                 atomic_long_inc(&mm->nr_ptes);
591                 pmd_populate(mm, pmd, new);
592                 new = NULL;
593         } else if (unlikely(pmd_trans_splitting(*pmd)))
594                 wait_split_huge_page = 1;
595         spin_unlock(ptl);
596         if (new)
597                 pte_free(mm, new);
598         if (wait_split_huge_page)
599                 wait_split_huge_page(vma->anon_vma, pmd);
600         return 0;
601 }
602 
603 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
604 {
605         pte_t *new = pte_alloc_one_kernel(&init_mm, address);
606         if (!new)
607                 return -ENOMEM;
608 
609         smp_wmb(); /* See comment in __pte_alloc */
610 
611         spin_lock(&init_mm.page_table_lock);
612         if (likely(pmd_none(*pmd))) {   /* Has another populated it ? */
613                 pmd_populate_kernel(&init_mm, pmd, new);
614                 new = NULL;
615         } else
616                 VM_BUG_ON(pmd_trans_splitting(*pmd));
617         spin_unlock(&init_mm.page_table_lock);
618         if (new)
619                 pte_free_kernel(&init_mm, new);
620         return 0;
621 }
622 
623 static inline void init_rss_vec(int *rss)
624 {
625         memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
626 }
627 
628 static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
629 {
630         int i;
631 
632         if (current->mm == mm)
633                 sync_mm_rss(mm);
634         for (i = 0; i < NR_MM_COUNTERS; i++)
635                 if (rss[i])
636                         add_mm_counter(mm, i, rss[i]);
637 }
638 
639 /*
640  * This function is called to print an error when a bad pte
641  * is found. For example, we might have a PFN-mapped pte in
642  * a region that doesn't allow it.
643  *
644  * The calling function must still handle the error.
645  */
646 static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
647                           pte_t pte, struct page *page)
648 {
649         pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
650         pud_t *pud = pud_offset(pgd, addr);
651         pmd_t *pmd = pmd_offset(pud, addr);
652         struct address_space *mapping;
653         pgoff_t index;
654         static unsigned long resume;
655         static unsigned long nr_shown;
656         static unsigned long nr_unshown;
657 
658         /*
659          * Allow a burst of 60 reports, then keep quiet for that minute;
660          * or allow a steady drip of one report per second.
661          */
662         if (nr_shown == 60) {
663                 if (time_before(jiffies, resume)) {
664                         nr_unshown++;
665                         return;
666                 }
667                 if (nr_unshown) {
668                         printk(KERN_ALERT
669                                 "BUG: Bad page map: %lu messages suppressed\n",
670                                 nr_unshown);
671                         nr_unshown = 0;
672                 }
673                 nr_shown = 0;
674         }
675         if (nr_shown++ == 0)
676                 resume = jiffies + 60 * HZ;
677 
678         mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
679         index = linear_page_index(vma, addr);
680 
681         printk(KERN_ALERT
682                 "BUG: Bad page map in process %s  pte:%08llx pmd:%08llx\n",
683                 current->comm,
684                 (long long)pte_val(pte), (long long)pmd_val(*pmd));
685         if (page)
686                 dump_page(page, "bad pte");
687         printk(KERN_ALERT
688                 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
689                 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
690         /*
691          * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
692          */
693         if (vma->vm_ops)
694                 printk(KERN_ALERT "vma->vm_ops->fault: %pSR\n",
695                        vma->vm_ops->fault);
696         if (vma->vm_file)
697                 printk(KERN_ALERT "vma->vm_file->f_op->mmap: %pSR\n",
698                        vma->vm_file->f_op->mmap);
699         dump_stack();
700         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
701 }
702 
703 /*
704  * vm_normal_page -- This function gets the "struct page" associated with a pte.
705  *
706  * "Special" mappings do not wish to be associated with a "struct page" (either
707  * it doesn't exist, or it exists but they don't want to touch it). In this
708  * case, NULL is returned here. "Normal" mappings do have a struct page.
709  *
710  * There are 2 broad cases. Firstly, an architecture may define a pte_special()
711  * pte bit, in which case this function is trivial. Secondly, an architecture
712  * may not have a spare pte bit, which requires a more complicated scheme,
713  * described below.
714  *
715  * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
716  * special mapping (even if there are underlying and valid "struct pages").
717  * COWed pages of a VM_PFNMAP are always normal.
718  *
719  * The way we recognize COWed pages within VM_PFNMAP mappings is through the
720  * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
721  * set, and the vm_pgoff will point to the first PFN mapped: thus every special
722  * mapping will always honor the rule
723  *
724  *      pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
725  *
726  * And for normal mappings this is false.
727  *
728  * This restricts such mappings to be a linear translation from virtual address
729  * to pfn. To get around this restriction, we allow arbitrary mappings so long
730  * as the vma is not a COW mapping; in that case, we know that all ptes are
731  * special (because none can have been COWed).
732  *
733  *
734  * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
735  *
736  * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
737  * page" backing, however the difference is that _all_ pages with a struct
738  * page (that is, those where pfn_valid is true) are refcounted and considered
739  * normal pages by the VM. The disadvantage is that pages are refcounted
740  * (which can be slower and simply not an option for some PFNMAP users). The
741  * advantage is that we don't have to follow the strict linearity rule of
742  * PFNMAP mappings in order to support COWable mappings.
743  *
744  */
745 #ifdef __HAVE_ARCH_PTE_SPECIAL
746 # define HAVE_PTE_SPECIAL 1
747 #else
748 # define HAVE_PTE_SPECIAL 0
749 #endif
750 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
751                                 pte_t pte)
752 {
753         unsigned long pfn = pte_pfn(pte);
754 
755         if (HAVE_PTE_SPECIAL) {
756                 if (likely(!pte_special(pte)))
757                         goto check_pfn;
758                 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
759                         return NULL;
760                 if (!is_zero_pfn(pfn))
761                         print_bad_pte(vma, addr, pte, NULL);
762                 return NULL;
763         }
764 
765         /* !HAVE_PTE_SPECIAL case follows: */
766 
767         if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
768                 if (vma->vm_flags & VM_MIXEDMAP) {
769                         if (!pfn_valid(pfn))
770                                 return NULL;
771                         goto out;
772                 } else {
773                         unsigned long off;
774                         off = (addr - vma->vm_start) >> PAGE_SHIFT;
775                         if (pfn == vma->vm_pgoff + off)
776                                 return NULL;
777                         if (!is_cow_mapping(vma->vm_flags))
778                                 return NULL;
779                 }
780         }
781 
782         if (is_zero_pfn(pfn))
783                 return NULL;
784 check_pfn:
785         if (unlikely(pfn > highest_memmap_pfn)) {
786                 print_bad_pte(vma, addr, pte, NULL);
787                 return NULL;
788         }
789 
790         /*
791          * NOTE! We still have PageReserved() pages in the page tables.
792          * eg. VDSO mappings can cause them to exist.
793          */
794 out:
795         return pfn_to_page(pfn);
796 }
797 
798 /*
799  * copy one vm_area from one task to the other. Assumes the page tables
800  * already present in the new task to be cleared in the whole range
801  * covered by this vma.
802  */
803 
804 static inline unsigned long
805 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
806                 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
807                 unsigned long addr, int *rss)
808 {
809         unsigned long vm_flags = vma->vm_flags;
810         pte_t pte = *src_pte;
811         struct page *page;
812 
813         /* pte contains position in swap or file, so copy. */
814         if (unlikely(!pte_present(pte))) {
815                 if (!pte_file(pte)) {
816                         swp_entry_t entry = pte_to_swp_entry(pte);
817 
818                         if (likely(!non_swap_entry(entry))) {
819                                 if (swap_duplicate(entry) < 0)
820                                         return entry.val;
821 
822                                 /* make sure dst_mm is on swapoff's mmlist. */
823                                 if (unlikely(list_empty(&dst_mm->mmlist))) {
824                                         spin_lock(&mmlist_lock);
825                                         if (list_empty(&dst_mm->mmlist))
826                                                 list_add(&dst_mm->mmlist,
827                                                          &src_mm->mmlist);
828                                         spin_unlock(&mmlist_lock);
829                                 }
830                                 rss[MM_SWAPENTS]++;
831                         } else if (is_migration_entry(entry)) {
832                                 page = migration_entry_to_page(entry);
833 
834                                 if (PageAnon(page))
835                                         rss[MM_ANONPAGES]++;
836                                 else
837                                         rss[MM_FILEPAGES]++;
838 
839                                 if (is_write_migration_entry(entry) &&
840                                     is_cow_mapping(vm_flags)) {
841                                         /*
842                                          * COW mappings require pages in both
843                                          * parent and child to be set to read.
844                                          */
845                                         make_migration_entry_read(&entry);
846                                         pte = swp_entry_to_pte(entry);
847                                         if (pte_swp_soft_dirty(*src_pte))
848                                                 pte = pte_swp_mksoft_dirty(pte);
849                                         set_pte_at(src_mm, addr, src_pte, pte);
850                                 }
851                         }
852                 }
853                 goto out_set_pte;
854         }
855 
856         /*
857          * If it's a COW mapping, write protect it both
858          * in the parent and the child
859          */
860         if (is_cow_mapping(vm_flags)) {
861                 ptep_set_wrprotect(src_mm, addr, src_pte);
862                 pte = pte_wrprotect(pte);
863         }
864 
865         /*
866          * If it's a shared mapping, mark it clean in
867          * the child
868          */
869         if (vm_flags & VM_SHARED)
870                 pte = pte_mkclean(pte);
871         pte = pte_mkold(pte);
872 
873         page = vm_normal_page(vma, addr, pte);
874         if (page) {
875                 get_page(page);
876                 page_dup_rmap(page);
877                 if (PageAnon(page))
878                         rss[MM_ANONPAGES]++;
879                 else
880                         rss[MM_FILEPAGES]++;
881         }
882 
883 out_set_pte:
884         set_pte_at(dst_mm, addr, dst_pte, pte);
885         return 0;
886 }
887 
888 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
889                    pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
890                    unsigned long addr, unsigned long end)
891 {
892         pte_t *orig_src_pte, *orig_dst_pte;
893         pte_t *src_pte, *dst_pte;
894         spinlock_t *src_ptl, *dst_ptl;
895         int progress = 0;
896         int rss[NR_MM_COUNTERS];
897         swp_entry_t entry = (swp_entry_t){0};
898 
899 again:
900         init_rss_vec(rss);
901 
902         dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
903         if (!dst_pte)
904                 return -ENOMEM;
905         src_pte = pte_offset_map(src_pmd, addr);
906         src_ptl = pte_lockptr(src_mm, src_pmd);
907         spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
908         orig_src_pte = src_pte;
909         orig_dst_pte = dst_pte;
910         arch_enter_lazy_mmu_mode();
911 
912         do {
913                 /*
914                  * We are holding two locks at this point - either of them
915                  * could generate latencies in another task on another CPU.
916                  */
917                 if (progress >= 32) {
918                         progress = 0;
919                         if (need_resched() ||
920                             spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
921                                 break;
922                 }
923                 if (pte_none(*src_pte)) {
924                         progress++;
925                         continue;
926                 }
927                 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
928                                                         vma, addr, rss);
929                 if (entry.val)
930                         break;
931                 progress += 8;
932         } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
933 
934         arch_leave_lazy_mmu_mode();
935         spin_unlock(src_ptl);
936         pte_unmap(orig_src_pte);
937         add_mm_rss_vec(dst_mm, rss);
938         pte_unmap_unlock(orig_dst_pte, dst_ptl);
939         cond_resched();
940 
941         if (entry.val) {
942                 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
943                         return -ENOMEM;
944                 progress = 0;
945         }
946         if (addr != end)
947                 goto again;
948         return 0;
949 }
950 
951 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
952                 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
953                 unsigned long addr, unsigned long end)
954 {
955         pmd_t *src_pmd, *dst_pmd;
956         unsigned long next;
957 
958         dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
959         if (!dst_pmd)
960                 return -ENOMEM;
961         src_pmd = pmd_offset(src_pud, addr);
962         do {
963                 next = pmd_addr_end(addr, end);
964                 if (pmd_trans_huge(*src_pmd)) {
965                         int err;
966                         VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
967                         err = copy_huge_pmd(dst_mm, src_mm,
968                                             dst_pmd, src_pmd, addr, vma);
969                         if (err == -ENOMEM)
970                                 return -ENOMEM;
971                         if (!err)
972                                 continue;
973                         /* fall through */
974                 }
975                 if (pmd_none_or_clear_bad(src_pmd))
976                         continue;
977                 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
978                                                 vma, addr, next))
979                         return -ENOMEM;
980         } while (dst_pmd++, src_pmd++, addr = next, addr != end);
981         return 0;
982 }
983 
984 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
985                 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
986                 unsigned long addr, unsigned long end)
987 {
988         pud_t *src_pud, *dst_pud;
989         unsigned long next;
990 
991         dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
992         if (!dst_pud)
993                 return -ENOMEM;
994         src_pud = pud_offset(src_pgd, addr);
995         do {
996                 next = pud_addr_end(addr, end);
997                 if (pud_none_or_clear_bad(src_pud))
998                         continue;
999                 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
1000                                                 vma, addr, next))
1001                         return -ENOMEM;
1002         } while (dst_pud++, src_pud++, addr = next, addr != end);
1003         return 0;
1004 }
1005 
1006 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1007                 struct vm_area_struct *vma)
1008 {
1009         pgd_t *src_pgd, *dst_pgd;
1010         unsigned long next;
1011         unsigned long addr = vma->vm_start;
1012         unsigned long end = vma->vm_end;
1013         unsigned long mmun_start;       /* For mmu_notifiers */
1014         unsigned long mmun_end;         /* For mmu_notifiers */
1015         bool is_cow;
1016         int ret;
1017 
1018         /*
1019          * Don't copy ptes where a page fault will fill them correctly.
1020          * Fork becomes much lighter when there are big shared or private
1021          * readonly mappings. The tradeoff is that copy_page_range is more
1022          * efficient than faulting.
1023          */
1024         if (!(vma->vm_flags & (VM_HUGETLB | VM_NONLINEAR |
1025                                VM_PFNMAP | VM_MIXEDMAP))) {
1026                 if (!vma->anon_vma)
1027                         return 0;
1028         }
1029 
1030         if (is_vm_hugetlb_page(vma))
1031                 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
1032 
1033         if (unlikely(vma->vm_flags & VM_PFNMAP)) {
1034                 /*
1035                  * We do not free on error cases below as remove_vma
1036                  * gets called on error from higher level routine
1037                  */
1038                 ret = track_pfn_copy(vma);
1039                 if (ret)
1040                         return ret;
1041         }
1042 
1043         /*
1044          * We need to invalidate the secondary MMU mappings only when
1045          * there could be a permission downgrade on the ptes of the
1046          * parent mm. And a permission downgrade will only happen if
1047          * is_cow_mapping() returns true.
1048          */
1049         is_cow = is_cow_mapping(vma->vm_flags);
1050         mmun_start = addr;
1051         mmun_end   = end;
1052         if (is_cow)
1053                 mmu_notifier_invalidate_range_start(src_mm, mmun_start,
1054                                                     mmun_end);
1055 
1056         ret = 0;
1057         dst_pgd = pgd_offset(dst_mm, addr);
1058         src_pgd = pgd_offset(src_mm, addr);
1059         do {
1060                 next = pgd_addr_end(addr, end);
1061                 if (pgd_none_or_clear_bad(src_pgd))
1062                         continue;
1063                 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
1064                                             vma, addr, next))) {
1065                         ret = -ENOMEM;
1066                         break;
1067                 }
1068         } while (dst_pgd++, src_pgd++, addr = next, addr != end);
1069 
1070         if (is_cow)
1071                 mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end);
1072         return ret;
1073 }
1074 
1075 static unsigned long zap_pte_range(struct mmu_gather *tlb,
1076                                 struct vm_area_struct *vma, pmd_t *pmd,
1077                                 unsigned long addr, unsigned long end,
1078                                 struct zap_details *details)
1079 {
1080         struct mm_struct *mm = tlb->mm;
1081         int force_flush = 0;
1082         int rss[NR_MM_COUNTERS];
1083         spinlock_t *ptl;
1084         pte_t *start_pte;
1085         pte_t *pte;
1086 
1087 again:
1088         init_rss_vec(rss);
1089         start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
1090         pte = start_pte;
1091         arch_enter_lazy_mmu_mode();
1092         do {
1093                 pte_t ptent = *pte;
1094                 if (pte_none(ptent)) {
1095                         continue;
1096                 }
1097 
1098                 if (pte_present(ptent)) {
1099                         struct page *page;
1100 
1101                         page = vm_normal_page(vma, addr, ptent);
1102                         if (unlikely(details) && page) {
1103                                 /*
1104                                  * unmap_shared_mapping_pages() wants to
1105                                  * invalidate cache without truncating:
1106                                  * unmap shared but keep private pages.
1107                                  */
1108                                 if (details->check_mapping &&
1109                                     details->check_mapping != page->mapping)
1110                                         continue;
1111                                 /*
1112                                  * Each page->index must be checked when
1113                                  * invalidating or truncating nonlinear.
1114                                  */
1115                                 if (details->nonlinear_vma &&
1116                                     (page->index < details->first_index ||
1117                                      page->index > details->last_index))
1118                                         continue;
1119                         }
1120                         ptent = ptep_get_and_clear_full(mm, addr, pte,
1121                                                         tlb->fullmm);
1122                         tlb_remove_tlb_entry(tlb, pte, addr);
1123                         if (unlikely(!page))
1124                                 continue;
1125                         if (unlikely(details) && details->nonlinear_vma
1126                             && linear_page_index(details->nonlinear_vma,
1127                                                 addr) != page->index) {
1128                                 pte_t ptfile = pgoff_to_pte(page->index);
1129                                 if (pte_soft_dirty(ptent))
1130                                         ptfile = pte_file_mksoft_dirty(ptfile);
1131                                 set_pte_at(mm, addr, pte, ptfile);
1132                         }
1133                         if (PageAnon(page))
1134                                 rss[MM_ANONPAGES]--;
1135                         else {
1136                                 if (pte_dirty(ptent)) {
1137                                         force_flush = 1;
1138                                         set_page_dirty(page);
1139                                 }
1140                                 if (pte_young(ptent) &&
1141                                     likely(!(vma->vm_flags & VM_SEQ_READ)))
1142                                         mark_page_accessed(page);
1143                                 rss[MM_FILEPAGES]--;
1144                         }
1145                         page_remove_rmap(page);
1146                         if (unlikely(page_mapcount(page) < 0))
1147                                 print_bad_pte(vma, addr, ptent, page);
1148                         if (unlikely(!__tlb_remove_page(tlb, page))) {
1149                                 force_flush = 1;
1150                                 addr += PAGE_SIZE;
1151                                 break;
1152                         }
1153                         continue;
1154                 }
1155                 /*
1156                  * If details->check_mapping, we leave swap entries;
1157                  * if details->nonlinear_vma, we leave file entries.
1158                  */
1159                 if (unlikely(details))
1160                         continue;
1161                 if (pte_file(ptent)) {
1162                         if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
1163                                 print_bad_pte(vma, addr, ptent, NULL);
1164                 } else {
1165                         swp_entry_t entry = pte_to_swp_entry(ptent);
1166 
1167                         if (!non_swap_entry(entry))
1168                                 rss[MM_SWAPENTS]--;
1169                         else if (is_migration_entry(entry)) {
1170                                 struct page *page;
1171 
1172                                 page = migration_entry_to_page(entry);
1173 
1174                                 if (PageAnon(page))
1175                                         rss[MM_ANONPAGES]--;
1176                                 else
1177                                         rss[MM_FILEPAGES]--;
1178                         }
1179                         if (unlikely(!free_swap_and_cache(entry)))
1180                                 print_bad_pte(vma, addr, ptent, NULL);
1181                 }
1182                 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
1183         } while (pte++, addr += PAGE_SIZE, addr != end);
1184 
1185         add_mm_rss_vec(mm, rss);
1186         arch_leave_lazy_mmu_mode();
1187 
1188         /* Do the actual TLB flush before dropping ptl */
1189         if (force_flush) {
1190                 unsigned long old_end;
1191 
1192                 /*
1193                  * Flush the TLB just for the previous segment,
1194                  * then update the range to be the remaining
1195                  * TLB range.
1196                  */
1197                 old_end = tlb->end;
1198                 tlb->end = addr;
1199                 tlb_flush_mmu_tlbonly(tlb);
1200                 tlb->start = addr;
1201                 tlb->end = old_end;
1202         }
1203         pte_unmap_unlock(start_pte, ptl);
1204 
1205         /*
1206          * If we forced a TLB flush (either due to running out of
1207          * batch buffers or because we needed to flush dirty TLB
1208          * entries before releasing the ptl), free the batched
1209          * memory too. Restart if we didn't do everything.
1210          */
1211         if (force_flush) {
1212                 force_flush = 0;
1213                 tlb_flush_mmu_free(tlb);
1214 
1215                 if (addr != end)
1216                         goto again;
1217         }
1218 
1219         return addr;
1220 }
1221 
1222 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
1223                                 struct vm_area_struct *vma, pud_t *pud,
1224                                 unsigned long addr, unsigned long end,
1225                                 struct zap_details *details)
1226 {
1227         pmd_t *pmd;
1228         unsigned long next;
1229 
1230         pmd = pmd_offset(pud, addr);
1231         do {
1232                 next = pmd_addr_end(addr, end);
1233                 if (pmd_trans_huge(*pmd)) {
1234                         if (next - addr != HPAGE_PMD_SIZE) {
1235 #ifdef CONFIG_DEBUG_VM
1236                                 if (!rwsem_is_locked(&tlb->mm->mmap_sem)) {
1237                                         pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n",
1238                                                 __func__, addr, end,
1239                                                 vma->vm_start,
1240                                                 vma->vm_end);
1241                                         BUG();
1242                                 }
1243 #endif
1244                                 split_huge_page_pmd(vma, addr, pmd);
1245                         } else if (zap_huge_pmd(tlb, vma, pmd, addr))
1246                                 goto next;
1247                         /* fall through */
1248                 }
1249                 /*
1250                  * Here there can be other concurrent MADV_DONTNEED or
1251                  * trans huge page faults running, and if the pmd is
1252                  * none or trans huge it can change under us. This is
1253                  * because MADV_DONTNEED holds the mmap_sem in read
1254                  * mode.
1255                  */
1256                 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
1257                         goto next;
1258                 next = zap_pte_range(tlb, vma, pmd, addr, next, details);
1259 next:
1260                 cond_resched();
1261         } while (pmd++, addr = next, addr != end);
1262 
1263         return addr;
1264 }
1265 
1266 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1267                                 struct vm_area_struct *vma, pgd_t *pgd,
1268                                 unsigned long addr, unsigned long end,
1269                                 struct zap_details *details)
1270 {
1271         pud_t *pud;
1272         unsigned long next;
1273 
1274         pud = pud_offset(pgd, addr);
1275         do {
1276                 next = pud_addr_end(addr, end);
1277                 if (pud_none_or_clear_bad(pud))
1278                         continue;
1279                 next = zap_pmd_range(tlb, vma, pud, addr, next, details);
1280         } while (pud++, addr = next, addr != end);
1281 
1282         return addr;
1283 }
1284 
1285 static void unmap_page_range(struct mmu_gather *tlb,
1286                              struct vm_area_struct *vma,
1287                              unsigned long addr, unsigned long end,
1288                              struct zap_details *details)
1289 {
1290         pgd_t *pgd;
1291         unsigned long next;
1292 
1293         if (details && !details->check_mapping && !details->nonlinear_vma)
1294                 details = NULL;
1295 
1296         BUG_ON(addr >= end);
1297         tlb_start_vma(tlb, vma);
1298         pgd = pgd_offset(vma->vm_mm, addr);
1299         do {
1300                 next = pgd_addr_end(addr, end);
1301                 if (pgd_none_or_clear_bad(pgd))
1302                         continue;
1303                 next = zap_pud_range(tlb, vma, pgd, addr, next, details);
1304         } while (pgd++, addr = next, addr != end);
1305         tlb_end_vma(tlb, vma);
1306 }
1307 
1308 
1309 static void unmap_single_vma(struct mmu_gather *tlb,
1310                 struct vm_area_struct *vma, unsigned long start_addr,
1311                 unsigned long end_addr,
1312                 struct zap_details *details)
1313 {
1314         unsigned long start = max(vma->vm_start, start_addr);
1315         unsigned long end;
1316 
1317         if (start >= vma->vm_end)
1318                 return;
1319         end = min(vma->vm_end, end_addr);
1320         if (end <= vma->vm_start)
1321                 return;
1322 
1323         if (vma->vm_file)
1324                 uprobe_munmap(vma, start, end);
1325 
1326         if (unlikely(vma->vm_flags & VM_PFNMAP))
1327                 untrack_pfn(vma, 0, 0);
1328 
1329         if (start != end) {
1330                 if (unlikely(is_vm_hugetlb_page(vma))) {
1331                         /*
1332                          * It is undesirable to test vma->vm_file as it
1333                          * should be non-null for valid hugetlb area.
1334                          * However, vm_file will be NULL in the error
1335                          * cleanup path of mmap_region. When
1336                          * hugetlbfs ->mmap method fails,
1337                          * mmap_region() nullifies vma->vm_file
1338                          * before calling this function to clean up.
1339                          * Since no pte has actually been setup, it is
1340                          * safe to do nothing in this case.
1341                          */
1342                         if (vma->vm_file) {
1343                                 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
1344                                 __unmap_hugepage_range_final(tlb, vma, start, end, NULL);
1345                                 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
1346                         }
1347                 } else
1348                         unmap_page_range(tlb, vma, start, end, details);
1349         }
1350 }
1351 
1352 /**
1353  * unmap_vmas - unmap a range of memory covered by a list of vma's
1354  * @tlb: address of the caller's struct mmu_gather
1355  * @vma: the starting vma
1356  * @start_addr: virtual address at which to start unmapping
1357  * @end_addr: virtual address at which to end unmapping
1358  *
1359  * Unmap all pages in the vma list.
1360  *
1361  * Only addresses between `start' and `end' will be unmapped.
1362  *
1363  * The VMA list must be sorted in ascending virtual address order.
1364  *
1365  * unmap_vmas() assumes that the caller will flush the whole unmapped address
1366  * range after unmap_vmas() returns.  So the only responsibility here is to
1367  * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1368  * drops the lock and schedules.
1369  */
1370 void unmap_vmas(struct mmu_gather *tlb,
1371                 struct vm_area_struct *vma, unsigned long start_addr,
1372                 unsigned long end_addr)
1373 {
1374         struct mm_struct *mm = vma->vm_mm;
1375 
1376         mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1377         for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
1378                 unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
1379         mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1380 }
1381 
1382 /**
1383  * zap_page_range - remove user pages in a given range
1384  * @vma: vm_area_struct holding the applicable pages
1385  * @start: starting address of pages to zap
1386  * @size: number of bytes to zap
1387  * @details: details of nonlinear truncation or shared cache invalidation
1388  *
1389  * Caller must protect the VMA list
1390  */
1391 void zap_page_range(struct vm_area_struct *vma, unsigned long start,
1392                 unsigned long size, struct zap_details *details)
1393 {
1394         struct mm_struct *mm = vma->vm_mm;
1395         struct mmu_gather tlb;
1396         unsigned long end = start + size;
1397 
1398         lru_add_drain();
1399         tlb_gather_mmu(&tlb, mm, start, end);
1400         update_hiwater_rss(mm);
1401         mmu_notifier_invalidate_range_start(mm, start, end);
1402         for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
1403                 unmap_single_vma(&tlb, vma, start, end, details);
1404         mmu_notifier_invalidate_range_end(mm, start, end);
1405         tlb_finish_mmu(&tlb, start, end);
1406 }
1407 
1408 /**
1409  * zap_page_range_single - remove user pages in a given range
1410  * @vma: vm_area_struct holding the applicable pages
1411  * @address: starting address of pages to zap
1412  * @size: number of bytes to zap
1413  * @details: details of nonlinear truncation or shared cache invalidation
1414  *
1415  * The range must fit into one VMA.
1416  */
1417 static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
1418                 unsigned long size, struct zap_details *details)
1419 {
1420         struct mm_struct *mm = vma->vm_mm;
1421         struct mmu_gather tlb;
1422         unsigned long end = address + size;
1423 
1424         lru_add_drain();
1425         tlb_gather_mmu(&tlb, mm, address, end);
1426         update_hiwater_rss(mm);
1427         mmu_notifier_invalidate_range_start(mm, address, end);
1428         unmap_single_vma(&tlb, vma, address, end, details);
1429         mmu_notifier_invalidate_range_end(mm, address, end);
1430         tlb_finish_mmu(&tlb, address, end);
1431 }
1432 
1433 /**
1434  * zap_vma_ptes - remove ptes mapping the vma
1435  * @vma: vm_area_struct holding ptes to be zapped
1436  * @address: starting address of pages to zap
1437  * @size: number of bytes to zap
1438  *
1439  * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1440  *
1441  * The entire address range must be fully contained within the vma.
1442  *
1443  * Returns 0 if successful.
1444  */
1445 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1446                 unsigned long size)
1447 {
1448         if (address < vma->vm_start || address + size > vma->vm_end ||
1449                         !(vma->vm_flags & VM_PFNMAP))
1450                 return -1;
1451         zap_page_range_single(vma, address, size, NULL);
1452         return 0;
1453 }
1454 EXPORT_SYMBOL_GPL(zap_vma_ptes);
1455 
1456 pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1457                         spinlock_t **ptl)
1458 {
1459         pgd_t * pgd = pgd_offset(mm, addr);
1460         pud_t * pud = pud_alloc(mm, pgd, addr);
1461         if (pud) {
1462                 pmd_t * pmd = pmd_alloc(mm, pud, addr);
1463                 if (pmd) {
1464                         VM_BUG_ON(pmd_trans_huge(*pmd));
1465                         return pte_alloc_map_lock(mm, pmd, addr, ptl);
1466                 }
1467         }
1468         return NULL;
1469 }
1470 
1471 /*
1472  * This is the old fallback for page remapping.
1473  *
1474  * For historical reasons, it only allows reserved pages. Only
1475  * old drivers should use this, and they needed to mark their
1476  * pages reserved for the old functions anyway.
1477  */
1478 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1479                         struct page *page, pgprot_t prot)
1480 {
1481         struct mm_struct *mm = vma->vm_mm;
1482         int retval;
1483         pte_t *pte;
1484         spinlock_t *ptl;
1485 
1486         retval = -EINVAL;
1487         if (PageAnon(page))
1488                 goto out;
1489         retval = -ENOMEM;
1490         flush_dcache_page(page);
1491         pte = get_locked_pte(mm, addr, &ptl);
1492         if (!pte)
1493                 goto out;
1494         retval = -EBUSY;
1495         if (!pte_none(*pte))
1496                 goto out_unlock;
1497 
1498         /* Ok, finally just insert the thing.. */
1499         get_page(page);
1500         inc_mm_counter_fast(mm, MM_FILEPAGES);
1501         page_add_file_rmap(page);
1502         set_pte_at(mm, addr, pte, mk_pte(page, prot));
1503 
1504         retval = 0;
1505         pte_unmap_unlock(pte, ptl);
1506         return retval;
1507 out_unlock:
1508         pte_unmap_unlock(pte, ptl);
1509 out:
1510         return retval;
1511 }
1512 
1513 /**
1514  * vm_insert_page - insert single page into user vma
1515  * @vma: user vma to map to
1516  * @addr: target user address of this page
1517  * @page: source kernel page
1518  *
1519  * This allows drivers to insert individual pages they've allocated
1520  * into a user vma.
1521  *
1522  * The page has to be a nice clean _individual_ kernel allocation.
1523  * If you allocate a compound page, you need to have marked it as
1524  * such (__GFP_COMP), or manually just split the page up yourself
1525  * (see split_page()).
1526  *
1527  * NOTE! Traditionally this was done with "remap_pfn_range()" which
1528  * took an arbitrary page protection parameter. This doesn't allow
1529  * that. Your vma protection will have to be set up correctly, which
1530  * means that if you want a shared writable mapping, you'd better
1531  * ask for a shared writable mapping!
1532  *
1533  * The page does not need to be reserved.
1534  *
1535  * Usually this function is called from f_op->mmap() handler
1536  * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
1537  * Caller must set VM_MIXEDMAP on vma if it wants to call this
1538  * function from other places, for example from page-fault handler.
1539  */
1540 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1541                         struct page *page)
1542 {
1543         if (addr < vma->vm_start || addr >= vma->vm_end)
1544                 return -EFAULT;
1545         if (!page_count(page))
1546                 return -EINVAL;
1547         if (!(vma->vm_flags & VM_MIXEDMAP)) {
1548                 BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem));
1549                 BUG_ON(vma->vm_flags & VM_PFNMAP);
1550                 vma->vm_flags |= VM_MIXEDMAP;
1551         }
1552         return insert_page(vma, addr, page, vma->vm_page_prot);
1553 }
1554 EXPORT_SYMBOL(vm_insert_page);
1555 
1556 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1557                         unsigned long pfn, pgprot_t prot)
1558 {
1559         struct mm_struct *mm = vma->vm_mm;
1560         int retval;
1561         pte_t *pte, entry;
1562         spinlock_t *ptl;
1563 
1564         retval = -ENOMEM;
1565         pte = get_locked_pte(mm, addr, &ptl);
1566         if (!pte)
1567                 goto out;
1568         retval = -EBUSY;
1569         if (!pte_none(*pte))
1570                 goto out_unlock;
1571 
1572         /* Ok, finally just insert the thing.. */
1573         entry = pte_mkspecial(pfn_pte(pfn, prot));
1574         set_pte_at(mm, addr, pte, entry);
1575         update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
1576 
1577         retval = 0;
1578 out_unlock:
1579         pte_unmap_unlock(pte, ptl);
1580 out:
1581         return retval;
1582 }
1583 
1584 /**
1585  * vm_insert_pfn - insert single pfn into user vma
1586  * @vma: user vma to map to
1587  * @addr: target user address of this page
1588  * @pfn: source kernel pfn
1589  *
1590  * Similar to vm_insert_page, this allows drivers to insert individual pages
1591  * they've allocated into a user vma. Same comments apply.
1592  *
1593  * This function should only be called from a vm_ops->fault handler, and
1594  * in that case the handler should return NULL.
1595  *
1596  * vma cannot be a COW mapping.
1597  *
1598  * As this is called only for pages that do not currently exist, we
1599  * do not need to flush old virtual caches or the TLB.
1600  */
1601 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1602                         unsigned long pfn)
1603 {
1604         int ret;
1605         pgprot_t pgprot = vma->vm_page_prot;
1606         /*
1607          * Technically, architectures with pte_special can avoid all these
1608          * restrictions (same for remap_pfn_range).  However we would like
1609          * consistency in testing and feature parity among all, so we should
1610          * try to keep these invariants in place for everybody.
1611          */
1612         BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1613         BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1614                                                 (VM_PFNMAP|VM_MIXEDMAP));
1615         BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1616         BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
1617 
1618         if (addr < vma->vm_start || addr >= vma->vm_end)
1619                 return -EFAULT;
1620         if (track_pfn_insert(vma, &pgprot, pfn))
1621                 return -EINVAL;
1622 
1623         ret = insert_pfn(vma, addr, pfn, pgprot);
1624 
1625         return ret;
1626 }
1627 EXPORT_SYMBOL(vm_insert_pfn);
1628 
1629 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1630                         unsigned long pfn)
1631 {
1632         BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1633 
1634         if (addr < vma->vm_start || addr >= vma->vm_end)
1635                 return -EFAULT;
1636 
1637         /*
1638          * If we don't have pte special, then we have to use the pfn_valid()
1639          * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1640          * refcount the page if pfn_valid is true (hence insert_page rather
1641          * than insert_pfn).  If a zero_pfn were inserted into a VM_MIXEDMAP
1642          * without pte special, it would there be refcounted as a normal page.
1643          */
1644         if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1645                 struct page *page;
1646 
1647                 page = pfn_to_page(pfn);
1648                 return insert_page(vma, addr, page, vma->vm_page_prot);
1649         }
1650         return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1651 }
1652 EXPORT_SYMBOL(vm_insert_mixed);
1653 
1654 /*
1655  * maps a range of physical memory into the requested pages. the old
1656  * mappings are removed. any references to nonexistent pages results
1657  * in null mappings (currently treated as "copy-on-access")
1658  */
1659 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1660                         unsigned long addr, unsigned long end,
1661                         unsigned long pfn, pgprot_t prot)
1662 {
1663         pte_t *pte;
1664         spinlock_t *ptl;
1665 
1666         pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1667         if (!pte)
1668                 return -ENOMEM;
1669         arch_enter_lazy_mmu_mode();
1670         do {
1671                 BUG_ON(!pte_none(*pte));
1672                 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
1673                 pfn++;
1674         } while (pte++, addr += PAGE_SIZE, addr != end);
1675         arch_leave_lazy_mmu_mode();
1676         pte_unmap_unlock(pte - 1, ptl);
1677         return 0;
1678 }
1679 
1680 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1681                         unsigned long addr, unsigned long end,
1682                         unsigned long pfn, pgprot_t prot)
1683 {
1684         pmd_t *pmd;
1685         unsigned long next;
1686 
1687         pfn -= addr >> PAGE_SHIFT;
1688         pmd = pmd_alloc(mm, pud, addr);
1689         if (!pmd)
1690                 return -ENOMEM;
1691         VM_BUG_ON(pmd_trans_huge(*pmd));
1692         do {
1693                 next = pmd_addr_end(addr, end);
1694                 if (remap_pte_range(mm, pmd, addr, next,
1695                                 pfn + (addr >> PAGE_SHIFT), prot))
1696                         return -ENOMEM;
1697         } while (pmd++, addr = next, addr != end);
1698         return 0;
1699 }
1700 
1701 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1702                         unsigned long addr, unsigned long end,
1703                         unsigned long pfn, pgprot_t prot)
1704 {
1705         pud_t *pud;
1706         unsigned long next;
1707 
1708         pfn -= addr >> PAGE_SHIFT;
1709         pud = pud_alloc(mm, pgd, addr);
1710         if (!pud)
1711                 return -ENOMEM;
1712         do {
1713                 next = pud_addr_end(addr, end);
1714                 if (remap_pmd_range(mm, pud, addr, next,
1715                                 pfn + (addr >> PAGE_SHIFT), prot))
1716                         return -ENOMEM;
1717         } while (pud++, addr = next, addr != end);
1718         return 0;
1719 }
1720 
1721 /**
1722  * remap_pfn_range - remap kernel memory to userspace
1723  * @vma: user vma to map to
1724  * @addr: target user address to start at
1725  * @pfn: physical address of kernel memory
1726  * @size: size of map area
1727  * @prot: page protection flags for this mapping
1728  *
1729  *  Note: this is only safe if the mm semaphore is held when called.
1730  */
1731 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1732                     unsigned long pfn, unsigned long size, pgprot_t prot)
1733 {
1734         pgd_t *pgd;
1735         unsigned long next;
1736         unsigned long end = addr + PAGE_ALIGN(size);
1737         struct mm_struct *mm = vma->vm_mm;
1738         int err;
1739 
1740         /*
1741          * Physically remapped pages are special. Tell the
1742          * rest of the world about it:
1743          *   VM_IO tells people not to look at these pages
1744          *      (accesses can have side effects).
1745          *   VM_PFNMAP tells the core MM that the base pages are just
1746          *      raw PFN mappings, and do not have a "struct page" associated
1747          *      with them.
1748          *   VM_DONTEXPAND
1749          *      Disable vma merging and expanding with mremap().
1750          *   VM_DONTDUMP
1751          *      Omit vma from core dump, even when VM_IO turned off.
1752          *
1753          * There's a horrible special case to handle copy-on-write
1754          * behaviour that some programs depend on. We mark the "original"
1755          * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1756          * See vm_normal_page() for details.
1757          */
1758         if (is_cow_mapping(vma->vm_flags)) {
1759                 if (addr != vma->vm_start || end != vma->vm_end)
1760                         return -EINVAL;
1761                 vma->vm_pgoff = pfn;
1762         }
1763 
1764         err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
1765         if (err)
1766                 return -EINVAL;
1767 
1768         vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1769 
1770         BUG_ON(addr >= end);
1771         pfn -= addr >> PAGE_SHIFT;
1772         pgd = pgd_offset(mm, addr);
1773         flush_cache_range(vma, addr, end);
1774         do {
1775                 next = pgd_addr_end(addr, end);
1776                 err = remap_pud_range(mm, pgd, addr, next,
1777                                 pfn + (addr >> PAGE_SHIFT), prot);
1778                 if (err)
1779                         break;
1780         } while (pgd++, addr = next, addr != end);
1781 
1782         if (err)
1783                 untrack_pfn(vma, pfn, PAGE_ALIGN(size));
1784 
1785         return err;
1786 }
1787 EXPORT_SYMBOL(remap_pfn_range);
1788 
1789 /**
1790  * vm_iomap_memory - remap memory to userspace
1791  * @vma: user vma to map to
1792  * @start: start of area
1793  * @len: size of area
1794  *
1795  * This is a simplified io_remap_pfn_range() for common driver use. The
1796  * driver just needs to give us the physical memory range to be mapped,
1797  * we'll figure out the rest from the vma information.
1798  *
1799  * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
1800  * whatever write-combining details or similar.
1801  */
1802 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1803 {
1804         unsigned long vm_len, pfn, pages;
1805 
1806         /* Check that the physical memory area passed in looks valid */
1807         if (start + len < start)
1808                 return -EINVAL;
1809         /*
1810          * You *really* shouldn't map things that aren't page-aligned,
1811          * but we've historically allowed it because IO memory might
1812          * just have smaller alignment.
1813          */
1814         len += start & ~PAGE_MASK;
1815         pfn = start >> PAGE_SHIFT;
1816         pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
1817         if (pfn + pages < pfn)
1818                 return -EINVAL;
1819 
1820         /* We start the mapping 'vm_pgoff' pages into the area */
1821         if (vma->vm_pgoff > pages)
1822                 return -EINVAL;
1823         pfn += vma->vm_pgoff;
1824         pages -= vma->vm_pgoff;
1825 
1826         /* Can we fit all of the mapping? */
1827         vm_len = vma->vm_end - vma->vm_start;
1828         if (vm_len >> PAGE_SHIFT > pages)
1829                 return -EINVAL;
1830 
1831         /* Ok, let it rip */
1832         return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1833 }
1834 EXPORT_SYMBOL(vm_iomap_memory);
1835 
1836 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1837                                      unsigned long addr, unsigned long end,
1838                                      pte_fn_t fn, void *data)
1839 {
1840         pte_t *pte;
1841         int err;
1842         pgtable_t token;
1843         spinlock_t *uninitialized_var(ptl);
1844 
1845         pte = (mm == &init_mm) ?
1846                 pte_alloc_kernel(pmd, addr) :
1847                 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1848         if (!pte)
1849                 return -ENOMEM;
1850 
1851         BUG_ON(pmd_huge(*pmd));
1852 
1853         arch_enter_lazy_mmu_mode();
1854 
1855         token = pmd_pgtable(*pmd);
1856 
1857         do {
1858                 err = fn(pte++, token, addr, data);
1859                 if (err)
1860                         break;
1861         } while (addr += PAGE_SIZE, addr != end);
1862 
1863         arch_leave_lazy_mmu_mode();
1864 
1865         if (mm != &init_mm)
1866                 pte_unmap_unlock(pte-1, ptl);
1867         return err;
1868 }
1869 
1870 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1871                                      unsigned long addr, unsigned long end,
1872                                      pte_fn_t fn, void *data)
1873 {
1874         pmd_t *pmd;
1875         unsigned long next;
1876         int err;
1877 
1878         BUG_ON(pud_huge(*pud));
1879 
1880         pmd = pmd_alloc(mm, pud, addr);
1881         if (!pmd)
1882                 return -ENOMEM;
1883         do {
1884                 next = pmd_addr_end(addr, end);
1885                 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1886                 if (err)
1887                         break;
1888         } while (pmd++, addr = next, addr != end);
1889         return err;
1890 }
1891 
1892 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1893                                      unsigned long addr, unsigned long end,
1894                                      pte_fn_t fn, void *data)
1895 {
1896         pud_t *pud;
1897         unsigned long next;
1898         int err;
1899 
1900         pud = pud_alloc(mm, pgd, addr);
1901         if (!pud)
1902                 return -ENOMEM;
1903         do {
1904                 next = pud_addr_end(addr, end);
1905                 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1906                 if (err)
1907                         break;
1908         } while (pud++, addr = next, addr != end);
1909         return err;
1910 }
1911 
1912 /*
1913  * Scan a region of virtual memory, filling in page tables as necessary
1914  * and calling a provided function on each leaf page table.
1915  */
1916 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1917                         unsigned long size, pte_fn_t fn, void *data)
1918 {
1919         pgd_t *pgd;
1920         unsigned long next;
1921         unsigned long end = addr + size;
1922         int err;
1923 
1924         BUG_ON(addr >= end);
1925         pgd = pgd_offset(mm, addr);
1926         do {
1927                 next = pgd_addr_end(addr, end);
1928                 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
1929                 if (err)
1930                         break;
1931         } while (pgd++, addr = next, addr != end);
1932 
1933         return err;
1934 }
1935 EXPORT_SYMBOL_GPL(apply_to_page_range);
1936 
1937 /*
1938  * handle_pte_fault chooses page fault handler according to an entry
1939  * which was read non-atomically.  Before making any commitment, on
1940  * those architectures or configurations (e.g. i386 with PAE) which
1941  * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
1942  * must check under lock before unmapping the pte and proceeding
1943  * (but do_wp_page is only called after already making such a check;
1944  * and do_anonymous_page can safely check later on).
1945  */
1946 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
1947                                 pte_t *page_table, pte_t orig_pte)
1948 {
1949         int same = 1;
1950 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1951         if (sizeof(pte_t) > sizeof(unsigned long)) {
1952                 spinlock_t *ptl = pte_lockptr(mm, pmd);
1953                 spin_lock(ptl);
1954                 same = pte_same(*page_table, orig_pte);
1955                 spin_unlock(ptl);
1956         }
1957 #endif
1958         pte_unmap(page_table);
1959         return same;
1960 }
1961 
1962 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
1963 {
1964         debug_dma_assert_idle(src);
1965 
1966         /*
1967          * If the source page was a PFN mapping, we don't have
1968          * a "struct page" for it. We do a best-effort copy by
1969          * just copying from the original user address. If that
1970          * fails, we just zero-fill it. Live with it.
1971          */
1972         if (unlikely(!src)) {
1973                 void *kaddr = kmap_atomic(dst);
1974                 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1975 
1976                 /*
1977                  * This really shouldn't fail, because the page is there
1978                  * in the page tables. But it might just be unreadable,
1979                  * in which case we just give up and fill the result with
1980                  * zeroes.
1981                  */
1982                 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
1983                         clear_page(kaddr);
1984                 kunmap_atomic(kaddr);
1985                 flush_dcache_page(dst);
1986         } else
1987                 copy_user_highpage(dst, src, va, vma);
1988 }
1989 
1990 /*
1991  * Notify the address space that the page is about to become writable so that
1992  * it can prohibit this or wait for the page to get into an appropriate state.
1993  *
1994  * We do this without the lock held, so that it can sleep if it needs to.
1995  */
1996 static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page,
1997                unsigned long address)
1998 {
1999         struct vm_fault vmf;
2000         int ret;
2001 
2002         vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2003         vmf.pgoff = page->index;
2004         vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2005         vmf.page = page;
2006 
2007         ret = vma->vm_ops->page_mkwrite(vma, &vmf);
2008         if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2009                 return ret;
2010         if (unlikely(!(ret & VM_FAULT_LOCKED))) {
2011                 lock_page(page);
2012                 if (!page->mapping) {
2013                         unlock_page(page);
2014                         return 0; /* retry */
2015                 }
2016                 ret |= VM_FAULT_LOCKED;
2017         } else
2018                 VM_BUG_ON_PAGE(!PageLocked(page), page);
2019         return ret;
2020 }
2021 
2022 /*
2023  * This routine handles present pages, when users try to write
2024  * to a shared page. It is done by copying the page to a new address
2025  * and decrementing the shared-page counter for the old page.
2026  *
2027  * Note that this routine assumes that the protection checks have been
2028  * done by the caller (the low-level page fault routine in most cases).
2029  * Thus we can safely just mark it writable once we've done any necessary
2030  * COW.
2031  *
2032  * We also mark the page dirty at this point even though the page will
2033  * change only once the write actually happens. This avoids a few races,
2034  * and potentially makes it more efficient.
2035  *
2036  * We enter with non-exclusive mmap_sem (to exclude vma changes,
2037  * but allow concurrent faults), with pte both mapped and locked.
2038  * We return with mmap_sem still held, but pte unmapped and unlocked.
2039  */
2040 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2041                 unsigned long address, pte_t *page_table, pmd_t *pmd,
2042                 spinlock_t *ptl, pte_t orig_pte)
2043         __releases(ptl)
2044 {
2045         struct page *old_page, *new_page = NULL;
2046         pte_t entry;
2047         int ret = 0;
2048         int page_mkwrite = 0;
2049         struct page *dirty_page = NULL;
2050         unsigned long mmun_start = 0;   /* For mmu_notifiers */
2051         unsigned long mmun_end = 0;     /* For mmu_notifiers */
2052         struct mem_cgroup *memcg;
2053 
2054         old_page = vm_normal_page(vma, address, orig_pte);
2055         if (!old_page) {
2056                 /*
2057                  * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
2058                  * VM_PFNMAP VMA.
2059                  *
2060                  * We should not cow pages in a shared writeable mapping.
2061                  * Just mark the pages writable as we can't do any dirty
2062                  * accounting on raw pfn maps.
2063                  */
2064                 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2065                                      (VM_WRITE|VM_SHARED))
2066                         goto reuse;
2067                 goto gotten;
2068         }
2069 
2070         /*
2071          * Take out anonymous pages first, anonymous shared vmas are
2072          * not dirty accountable.
2073          */
2074         if (PageAnon(old_page) && !PageKsm(old_page)) {
2075                 if (!trylock_page(old_page)) {
2076                         page_cache_get(old_page);
2077                         pte_unmap_unlock(page_table, ptl);
2078                         lock_page(old_page);
2079                         page_table = pte_offset_map_lock(mm, pmd, address,
2080                                                          &ptl);
2081                         if (!pte_same(*page_table, orig_pte)) {
2082                                 unlock_page(old_page);
2083                                 goto unlock;
2084                         }
2085                         page_cache_release(old_page);
2086                 }
2087                 if (reuse_swap_page(old_page)) {
2088                         /*
2089                          * The page is all ours.  Move it to our anon_vma so
2090                          * the rmap code will not search our parent or siblings.
2091                          * Protected against the rmap code by the page lock.
2092                          */
2093                         page_move_anon_rmap(old_page, vma, address);
2094                         unlock_page(old_page);
2095                         goto reuse;
2096                 }
2097                 unlock_page(old_page);
2098         } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2099                                         (VM_WRITE|VM_SHARED))) {
2100                 /*
2101                  * Only catch write-faults on shared writable pages,
2102                  * read-only shared pages can get COWed by
2103                  * get_user_pages(.write=1, .force=1).
2104                  */
2105                 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2106                         int tmp;
2107                         page_cache_get(old_page);
2108                         pte_unmap_unlock(page_table, ptl);
2109                         tmp = do_page_mkwrite(vma, old_page, address);
2110                         if (unlikely(!tmp || (tmp &
2111                                         (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
2112                                 page_cache_release(old_page);
2113                                 return tmp;
2114                         }
2115                         /*
2116                          * Since we dropped the lock we need to revalidate
2117                          * the PTE as someone else may have changed it.  If
2118                          * they did, we just return, as we can count on the
2119                          * MMU to tell us if they didn't also make it writable.
2120                          */
2121                         page_table = pte_offset_map_lock(mm, pmd, address,
2122                                                          &ptl);
2123                         if (!pte_same(*page_table, orig_pte)) {
2124                                 unlock_page(old_page);
2125                                 goto unlock;
2126                         }
2127 
2128                         page_mkwrite = 1;
2129                 }
2130                 dirty_page = old_page;
2131                 get_page(dirty_page);
2132 
2133 reuse:
2134                 /*
2135                  * Clear the pages cpupid information as the existing
2136                  * information potentially belongs to a now completely
2137                  * unrelated process.
2138                  */
2139                 if (old_page)
2140                         page_cpupid_xchg_last(old_page, (1 << LAST_CPUPID_SHIFT) - 1);
2141 
2142                 flush_cache_page(vma, address, pte_pfn(orig_pte));
2143                 entry = pte_mkyoung(orig_pte);
2144                 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2145                 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2146                         update_mmu_cache(vma, address, page_table);
2147                 pte_unmap_unlock(page_table, ptl);
2148                 ret |= VM_FAULT_WRITE;
2149 
2150                 if (!dirty_page)
2151                         return ret;
2152 
2153                 /*
2154                  * Yes, Virginia, this is actually required to prevent a race
2155                  * with clear_page_dirty_for_io() from clearing the page dirty
2156                  * bit after it clear all dirty ptes, but before a racing
2157                  * do_wp_page installs a dirty pte.
2158                  *
2159                  * do_shared_fault is protected similarly.
2160                  */
2161                 if (!page_mkwrite) {
2162                         wait_on_page_locked(dirty_page);
2163                         set_page_dirty_balance(dirty_page);
2164                         /* file_update_time outside page_lock */
2165                         if (vma->vm_file)
2166                                 file_update_time(vma->vm_file);
2167                 }
2168                 put_page(dirty_page);
2169                 if (page_mkwrite) {
2170                         struct address_space *mapping = dirty_page->mapping;
2171 
2172                         set_page_dirty(dirty_page);
2173                         unlock_page(dirty_page);
2174                         page_cache_release(dirty_page);
2175                         if (mapping)    {
2176                                 /*
2177                                  * Some device drivers do not set page.mapping
2178                                  * but still dirty their pages
2179                                  */
2180                                 balance_dirty_pages_ratelimited(mapping);
2181                         }
2182                 }
2183 
2184                 return ret;
2185         }
2186 
2187         /*
2188          * Ok, we need to copy. Oh, well..
2189          */
2190         page_cache_get(old_page);
2191 gotten:
2192         pte_unmap_unlock(page_table, ptl);
2193 
2194         if (unlikely(anon_vma_prepare(vma)))
2195                 goto oom;
2196 
2197         if (is_zero_pfn(pte_pfn(orig_pte))) {
2198                 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2199                 if (!new_page)
2200                         goto oom;
2201         } else {
2202                 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2203                 if (!new_page)
2204                         goto oom;
2205                 cow_user_page(new_page, old_page, address, vma);
2206         }
2207         __SetPageUptodate(new_page);
2208 
2209         if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg))
2210                 goto oom_free_new;
2211 
2212         mmun_start  = address & PAGE_MASK;
2213         mmun_end    = mmun_start + PAGE_SIZE;
2214         mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2215 
2216         /*
2217          * Re-check the pte - we dropped the lock
2218          */
2219         page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2220         if (likely(pte_same(*page_table, orig_pte))) {
2221                 if (old_page) {
2222                         if (!PageAnon(old_page)) {
2223                                 dec_mm_counter_fast(mm, MM_FILEPAGES);
2224                                 inc_mm_counter_fast(mm, MM_ANONPAGES);
2225                         }
2226                 } else
2227                         inc_mm_counter_fast(mm, MM_ANONPAGES);
2228                 flush_cache_page(vma, address, pte_pfn(orig_pte));
2229                 entry = mk_pte(new_page, vma->vm_page_prot);
2230                 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2231                 /*
2232                  * Clear the pte entry and flush it first, before updating the
2233                  * pte with the new entry. This will avoid a race condition
2234                  * seen in the presence of one thread doing SMC and another
2235                  * thread doing COW.
2236                  */
2237                 ptep_clear_flush(vma, address, page_table);
2238                 page_add_new_anon_rmap(new_page, vma, address);
2239                 mem_cgroup_commit_charge(new_page, memcg, false);
2240                 lru_cache_add_active_or_unevictable(new_page, vma);
2241                 /*
2242                  * We call the notify macro here because, when using secondary
2243                  * mmu page tables (such as kvm shadow page tables), we want the
2244                  * new page to be mapped directly into the secondary page table.
2245                  */
2246                 set_pte_at_notify(mm, address, page_table, entry);
2247                 update_mmu_cache(vma, address, page_table);
2248                 if (old_page) {
2249                         /*
2250                          * Only after switching the pte to the new page may
2251                          * we remove the mapcount here. Otherwise another
2252                          * process may come and find the rmap count decremented
2253                          * before the pte is switched to the new page, and
2254                          * "reuse" the old page writing into it while our pte
2255                          * here still points into it and can be read by other
2256                          * threads.
2257                          *
2258                          * The critical issue is to order this
2259                          * page_remove_rmap with the ptp_clear_flush above.
2260                          * Those stores are ordered by (if nothing else,)
2261                          * the barrier present in the atomic_add_negative
2262                          * in page_remove_rmap.
2263                          *
2264                          * Then the TLB flush in ptep_clear_flush ensures that
2265                          * no process can access the old page before the
2266                          * decremented mapcount is visible. And the old page
2267                          * cannot be reused until after the decremented
2268                          * mapcount is visible. So transitively, TLBs to
2269                          * old page will be flushed before it can be reused.
2270                          */
2271                         page_remove_rmap(old_page);
2272                 }
2273 
2274                 /* Free the old page.. */
2275                 new_page = old_page;
2276                 ret |= VM_FAULT_WRITE;
2277         } else
2278                 mem_cgroup_cancel_charge(new_page, memcg);
2279 
2280         if (new_page)
2281                 page_cache_release(new_page);
2282 unlock:
2283         pte_unmap_unlock(page_table, ptl);
2284         if (mmun_end > mmun_start)
2285                 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2286         if (old_page) {
2287                 /*
2288                  * Don't let another task, with possibly unlocked vma,
2289                  * keep the mlocked page.
2290                  */
2291                 if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) {
2292                         lock_page(old_page);    /* LRU manipulation */
2293                         munlock_vma_page(old_page);
2294                         unlock_page(old_page);
2295                 }
2296                 page_cache_release(old_page);
2297         }
2298         return ret;
2299 oom_free_new:
2300         page_cache_release(new_page);
2301 oom:
2302         if (old_page)
2303                 page_cache_release(old_page);
2304         return VM_FAULT_OOM;
2305 }
2306 
2307 static void unmap_mapping_range_vma(struct vm_area_struct *vma,
2308                 unsigned long start_addr, unsigned long end_addr,
2309                 struct zap_details *details)
2310 {
2311         zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
2312 }
2313 
2314 static inline void unmap_mapping_range_tree(struct rb_root *root,
2315                                             struct zap_details *details)
2316 {
2317         struct vm_area_struct *vma;
2318         pgoff_t vba, vea, zba, zea;
2319 
2320         vma_interval_tree_foreach(vma, root,
2321                         details->first_index, details->last_index) {
2322 
2323                 vba = vma->vm_pgoff;
2324                 vea = vba + vma_pages(vma) - 1;
2325                 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2326                 zba = details->first_index;
2327                 if (zba < vba)
2328                         zba = vba;
2329                 zea = details->last_index;
2330                 if (zea > vea)
2331                         zea = vea;
2332 
2333                 unmap_mapping_range_vma(vma,
2334                         ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2335                         ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2336                                 details);
2337         }
2338 }
2339 
2340 static inline void unmap_mapping_range_list(struct list_head *head,
2341                                             struct zap_details *details)
2342 {
2343         struct vm_area_struct *vma;
2344 
2345         /*
2346          * In nonlinear VMAs there is no correspondence between virtual address
2347          * offset and file offset.  So we must perform an exhaustive search
2348          * across *all* the pages in each nonlinear VMA, not just the pages
2349          * whose virtual address lies outside the file truncation point.
2350          */
2351         list_for_each_entry(vma, head, shared.nonlinear) {
2352                 details->nonlinear_vma = vma;
2353                 unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
2354         }
2355 }
2356 
2357 /**
2358  * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2359  * @mapping: the address space containing mmaps to be unmapped.
2360  * @holebegin: byte in first page to unmap, relative to the start of
2361  * the underlying file.  This will be rounded down to a PAGE_SIZE
2362  * boundary.  Note that this is different from truncate_pagecache(), which
2363  * must keep the partial page.  In contrast, we must get rid of
2364  * partial pages.
2365  * @holelen: size of prospective hole in bytes.  This will be rounded
2366  * up to a PAGE_SIZE boundary.  A holelen of zero truncates to the
2367  * end of the file.
2368  * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2369  * but 0 when invalidating pagecache, don't throw away private data.
2370  */
2371 void unmap_mapping_range(struct address_space *mapping,
2372                 loff_t const holebegin, loff_t const holelen, int even_cows)
2373 {
2374         struct zap_details details;
2375         pgoff_t hba = holebegin >> PAGE_SHIFT;
2376         pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2377 
2378         /* Check for overflow. */
2379         if (sizeof(holelen) > sizeof(hlen)) {
2380                 long long holeend =
2381                         (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2382                 if (holeend & ~(long long)ULONG_MAX)
2383                         hlen = ULONG_MAX - hba + 1;
2384         }
2385 
2386         details.check_mapping = even_cows? NULL: mapping;
2387         details.nonlinear_vma = NULL;
2388         details.first_index = hba;
2389         details.last_index = hba + hlen - 1;
2390         if (details.last_index < details.first_index)
2391                 details.last_index = ULONG_MAX;
2392 
2393 
2394         mutex_lock(&mapping->i_mmap_mutex);
2395         if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
2396                 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2397         if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2398                 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2399         mutex_unlock(&mapping->i_mmap_mutex);
2400 }
2401 EXPORT_SYMBOL(unmap_mapping_range);
2402 
2403 /*
2404  * We enter with non-exclusive mmap_sem (to exclude vma changes,
2405  * but allow concurrent faults), and pte mapped but not yet locked.
2406  * We return with pte unmapped and unlocked.
2407  *
2408  * We return with the mmap_sem locked or unlocked in the same cases
2409  * as does filemap_fault().
2410  */
2411 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2412                 unsigned long address, pte_t *page_table, pmd_t *pmd,
2413                 unsigned int flags, pte_t orig_pte)
2414 {
2415         spinlock_t *ptl;
2416         struct page *page, *swapcache;
2417         struct mem_cgroup *memcg;
2418         swp_entry_t entry;
2419         pte_t pte;
2420         int locked;
2421         int exclusive = 0;
2422         int ret = 0;
2423 
2424         if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2425                 goto out;
2426 
2427         entry = pte_to_swp_entry(orig_pte);
2428         if (unlikely(non_swap_entry(entry))) {
2429                 if (is_migration_entry(entry)) {
2430                         migration_entry_wait(mm, pmd, address);
2431                 } else if (is_hwpoison_entry(entry)) {
2432                         ret = VM_FAULT_HWPOISON;
2433                 } else {
2434                         print_bad_pte(vma, address, orig_pte, NULL);
2435                         ret = VM_FAULT_SIGBUS;
2436                 }
2437                 goto out;
2438         }
2439         delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2440         page = lookup_swap_cache(entry);
2441         if (!page) {
2442                 page = swapin_readahead(entry,
2443                                         GFP_HIGHUSER_MOVABLE, vma, address);
2444                 if (!page) {
2445                         /*
2446                          * Back out if somebody else faulted in this pte
2447                          * while we released the pte lock.
2448                          */
2449                         page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2450                         if (likely(pte_same(*page_table, orig_pte)))
2451                                 ret = VM_FAULT_OOM;
2452                         delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2453                         goto unlock;
2454                 }
2455 
2456                 /* Had to read the page from swap area: Major fault */
2457                 ret = VM_FAULT_MAJOR;
2458                 count_vm_event(PGMAJFAULT);
2459                 mem_cgroup_count_vm_event(mm, PGMAJFAULT);
2460         } else if (PageHWPoison(page)) {
2461                 /*
2462                  * hwpoisoned dirty swapcache pages are kept for killing
2463                  * owner processes (which may be unknown at hwpoison time)
2464                  */
2465                 ret = VM_FAULT_HWPOISON;
2466                 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2467                 swapcache = page;
2468                 goto out_release;
2469         }
2470 
2471         swapcache = page;
2472         locked = lock_page_or_retry(page, mm, flags);
2473 
2474         delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2475         if (!locked) {
2476                 ret |= VM_FAULT_RETRY;
2477                 goto out_release;
2478         }
2479 
2480         /*
2481          * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
2482          * release the swapcache from under us.  The page pin, and pte_same
2483          * test below, are not enough to exclude that.  Even if it is still
2484          * swapcache, we need to check that the page's swap has not changed.
2485          */
2486         if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
2487                 goto out_page;
2488 
2489         page = ksm_might_need_to_copy(page, vma, address);
2490         if (unlikely(!page)) {
2491                 ret = VM_FAULT_OOM;
2492                 page = swapcache;
2493                 goto out_page;
2494         }
2495 
2496         if (mem_cgroup_try_charge(page, mm, GFP_KERNEL, &memcg)) {
2497                 ret = VM_FAULT_OOM;
2498                 goto out_page;
2499         }
2500 
2501         /*
2502          * Back out if somebody else already faulted in this pte.
2503          */
2504         page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2505         if (unlikely(!pte_same(*page_table, orig_pte)))
2506                 goto out_nomap;
2507 
2508         if (unlikely(!PageUptodate(page))) {
2509                 ret = VM_FAULT_SIGBUS;
2510                 goto out_nomap;
2511         }
2512 
2513         /*
2514          * The page isn't present yet, go ahead with the fault.
2515          *
2516          * Be careful about the sequence of operations here.
2517          * To get its accounting right, reuse_swap_page() must be called
2518          * while the page is counted on swap but not yet in mapcount i.e.
2519          * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2520          * must be called after the swap_free(), or it will never succeed.
2521          */
2522 
2523         inc_mm_counter_fast(mm, MM_ANONPAGES);
2524         dec_mm_counter_fast(mm, MM_SWAPENTS);
2525         pte = mk_pte(page, vma->vm_page_prot);
2526         if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
2527                 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2528                 flags &= ~FAULT_FLAG_WRITE;
2529                 ret |= VM_FAULT_WRITE;
2530                 exclusive = 1;
2531         }
2532         flush_icache_page(vma, page);
2533         if (pte_swp_soft_dirty(orig_pte))
2534                 pte = pte_mksoft_dirty(pte);
2535         set_pte_at(mm, address, page_table, pte);
2536         if (page == swapcache) {
2537                 do_page_add_anon_rmap(page, vma, address, exclusive);
2538                 mem_cgroup_commit_charge(page, memcg, true);
2539         } else { /* ksm created a completely new copy */
2540                 page_add_new_anon_rmap(page, vma, address);
2541                 mem_cgroup_commit_charge(page, memcg, false);
2542                 lru_cache_add_active_or_unevictable(page, vma);
2543         }
2544 
2545         swap_free(entry);
2546         if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
2547                 try_to_free_swap(page);
2548         unlock_page(page);
2549         if (page != swapcache) {
2550                 /*
2551                  * Hold the lock to avoid the swap entry to be reused
2552                  * until we take the PT lock for the pte_same() check
2553                  * (to avoid false positives from pte_same). For
2554                  * further safety release the lock after the swap_free
2555                  * so that the swap count won't change under a
2556                  * parallel locked swapcache.
2557                  */
2558                 unlock_page(swapcache);
2559                 page_cache_release(swapcache);
2560         }
2561 
2562         if (flags & FAULT_FLAG_WRITE) {
2563                 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2564                 if (ret & VM_FAULT_ERROR)
2565                         ret &= VM_FAULT_ERROR;
2566                 goto out;
2567         }
2568 
2569         /* No need to invalidate - it was non-present before */
2570         update_mmu_cache(vma, address, page_table);
2571 unlock:
2572         pte_unmap_unlock(page_table, ptl);
2573 out:
2574         return ret;
2575 out_nomap:
2576         mem_cgroup_cancel_charge(page, memcg);
2577         pte_unmap_unlock(page_table, ptl);
2578 out_page:
2579         unlock_page(page);
2580 out_release:
2581         page_cache_release(page);
2582         if (page != swapcache) {
2583                 unlock_page(swapcache);
2584                 page_cache_release(swapcache);
2585         }
2586         return ret;
2587 }
2588 
2589 /*
2590  * This is like a special single-page "expand_{down|up}wards()",
2591  * except we must first make sure that 'address{-|+}PAGE_SIZE'
2592  * doesn't hit another vma.
2593  */
2594 static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
2595 {
2596         address &= PAGE_MASK;
2597         if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
2598                 struct vm_area_struct *prev = vma->vm_prev;
2599 
2600                 /*
2601                  * Is there a mapping abutting this one below?
2602                  *
2603                  * That's only ok if it's the same stack mapping
2604                  * that has gotten split..
2605                  */
2606                 if (prev && prev->vm_end == address)
2607                         return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
2608 
2609                 expand_downwards(vma, address - PAGE_SIZE);
2610         }
2611         if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
2612                 struct vm_area_struct *next = vma->vm_next;
2613 
2614                 /* As VM_GROWSDOWN but s/below/above/ */
2615                 if (next && next->vm_start == address + PAGE_SIZE)
2616                         return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
2617 
2618                 expand_upwards(vma, address + PAGE_SIZE);
2619         }
2620         return 0;
2621 }
2622 
2623 /*
2624  * We enter with non-exclusive mmap_sem (to exclude vma changes,
2625  * but allow concurrent faults), and pte mapped but not yet locked.
2626  * We return with mmap_sem still held, but pte unmapped and unlocked.
2627  */
2628 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2629                 unsigned long address, pte_t *page_table, pmd_t *pmd,
2630                 unsigned int flags)
2631 {
2632         struct mem_cgroup *memcg;
2633         struct page *page;
2634         spinlock_t *ptl;
2635         pte_t entry;
2636 
2637         pte_unmap(page_table);
2638 
2639         /* Check if we need to add a guard page to the stack */
2640         if (check_stack_guard_page(vma, address) < 0)
2641                 return VM_FAULT_SIGBUS;
2642 
2643         /* Use the zero-page for reads */
2644         if (!(flags & FAULT_FLAG_WRITE)) {
2645                 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2646                                                 vma->vm_page_prot));
2647                 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2648                 if (!pte_none(*page_table))
2649                         goto unlock;
2650                 goto setpte;
2651         }
2652 
2653         /* Allocate our own private page. */
2654         if (unlikely(anon_vma_prepare(vma)))
2655                 goto oom;
2656         page = alloc_zeroed_user_highpage_movable(vma, address);
2657         if (!page)
2658                 goto oom;
2659         /*
2660          * The memory barrier inside __SetPageUptodate makes sure that
2661          * preceeding stores to the page contents become visible before
2662          * the set_pte_at() write.
2663          */
2664         __SetPageUptodate(page);
2665 
2666         if (mem_cgroup_try_charge(page, mm, GFP_KERNEL, &memcg))
2667                 goto oom_free_page;
2668 
2669         entry = mk_pte(page, vma->vm_page_prot);
2670         if (vma->vm_flags & VM_WRITE)
2671                 entry = pte_mkwrite(pte_mkdirty(entry));
2672 
2673         page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2674         if (!pte_none(*page_table))
2675                 goto release;
2676 
2677         inc_mm_counter_fast(mm, MM_ANONPAGES);
2678         page_add_new_anon_rmap(page, vma, address);
2679         mem_cgroup_commit_charge(page, memcg, false);
2680         lru_cache_add_active_or_unevictable(page, vma);
2681 setpte:
2682         set_pte_at(mm, address, page_table, entry);
2683 
2684         /* No need to invalidate - it was non-present before */
2685         update_mmu_cache(vma, address, page_table);
2686 unlock:
2687         pte_unmap_unlock(page_table, ptl);
2688         return 0;
2689 release:
2690         mem_cgroup_cancel_charge(page, memcg);
2691         page_cache_release(page);
2692         goto unlock;
2693 oom_free_page:
2694         page_cache_release(page);
2695 oom:
2696         return VM_FAULT_OOM;
2697 }
2698 
2699 /*
2700  * The mmap_sem must have been held on entry, and may have been
2701  * released depending on flags and vma->vm_ops->fault() return value.
2702  * See filemap_fault() and __lock_page_retry().
2703  */
2704 static int __do_fault(struct vm_area_struct *vma, unsigned long address,
2705                 pgoff_t pgoff, unsigned int flags, struct page **page)
2706 {
2707         struct vm_fault vmf;
2708         int ret;
2709 
2710         vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2711         vmf.pgoff = pgoff;
2712         vmf.flags = flags;
2713         vmf.page = NULL;
2714 
2715         ret = vma->vm_ops->fault(vma, &vmf);
2716         if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
2717                 return ret;
2718 
2719         if (unlikely(PageHWPoison(vmf.page))) {
2720                 if (ret & VM_FAULT_LOCKED)
2721                         unlock_page(vmf.page);
2722                 page_cache_release(vmf.page);
2723                 return VM_FAULT_HWPOISON;
2724         }
2725 
2726         if (unlikely(!(ret & VM_FAULT_LOCKED)))
2727                 lock_page(vmf.page);
2728         else
2729                 VM_BUG_ON_PAGE(!PageLocked(vmf.page), vmf.page);
2730 
2731         *page = vmf.page;
2732         return ret;
2733 }
2734 
2735 /**
2736  * do_set_pte - setup new PTE entry for given page and add reverse page mapping.
2737  *
2738  * @vma: virtual memory area
2739  * @address: user virtual address
2740  * @page: page to map
2741  * @pte: pointer to target page table entry
2742  * @write: true, if new entry is writable
2743  * @anon: true, if it's anonymous page
2744  *
2745  * Caller must hold page table lock relevant for @pte.
2746  *
2747  * Target users are page handler itself and implementations of
2748  * vm_ops->map_pages.
2749  */
2750 void do_set_pte(struct vm_area_struct *vma, unsigned long address,
2751                 struct page *page, pte_t *pte, bool write, bool anon)
2752 {
2753         pte_t entry;
2754 
2755         flush_icache_page(vma, page);
2756         entry = mk_pte(page, vma->vm_page_prot);
2757         if (write)
2758                 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2759         else if (pte_file(*pte) && pte_file_soft_dirty(*pte))
2760                 entry = pte_mksoft_dirty(entry);
2761         if (anon) {
2762                 inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
2763                 page_add_new_anon_rmap(page, vma, address);
2764         } else {
2765                 inc_mm_counter_fast(vma->vm_mm, MM_FILEPAGES);
2766                 page_add_file_rmap(page);
2767         }
2768         set_pte_at(vma->vm_mm, address, pte, entry);
2769 
2770         /* no need to invalidate: a not-present page won't be cached */
2771         update_mmu_cache(vma, address, pte);
2772 }
2773 
2774 static unsigned long fault_around_bytes __read_mostly =
2775         rounddown_pow_of_two(65536);
2776 
2777 #ifdef CONFIG_DEBUG_FS
2778 static int fault_around_bytes_get(void *data, u64 *val)
2779 {
2780         *val = fault_around_bytes;
2781         return 0;
2782 }
2783 
2784 /*
2785  * fault_around_pages() and fault_around_mask() expects fault_around_bytes
2786  * rounded down to nearest page order. It's what do_fault_around() expects to
2787  * see.
2788  */
2789 static int fault_around_bytes_set(void *data, u64 val)
2790 {
2791         if (val / PAGE_SIZE > PTRS_PER_PTE)
2792                 return -EINVAL;
2793         if (val > PAGE_SIZE)
2794                 fault_around_bytes = rounddown_pow_of_two(val);
2795         else
2796                 fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */
2797         return 0;
2798 }
2799 DEFINE_SIMPLE_ATTRIBUTE(fault_around_bytes_fops,
2800                 fault_around_bytes_get, fault_around_bytes_set, "%llu\n");
2801 
2802 static int __init fault_around_debugfs(void)
2803 {
2804         void *ret;
2805 
2806         ret = debugfs_create_file("fault_around_bytes", 0644, NULL, NULL,
2807                         &fault_around_bytes_fops);
2808         if (!ret)
2809                 pr_warn("Failed to create fault_around_bytes in debugfs");
2810         return 0;
2811 }
2812 late_initcall(fault_around_debugfs);
2813 #endif
2814 
2815 /*
2816  * do_fault_around() tries to map few pages around the fault address. The hope
2817  * is that the pages will be needed soon and this will lower the number of
2818  * faults to handle.
2819  *
2820  * It uses vm_ops->map_pages() to map the pages, which skips the page if it's
2821  * not ready to be mapped: not up-to-date, locked, etc.
2822  *
2823  * This function is called with the page table lock taken. In the split ptlock
2824  * case the page table lock only protects only those entries which belong to
2825  * the page table corresponding to the fault address.
2826  *
2827  * This function doesn't cross the VMA boundaries, in order to call map_pages()
2828  * only once.
2829  *
2830  * fault_around_pages() defines how many pages we'll try to map.
2831  * do_fault_around() expects it to return a power of two less than or equal to
2832  * PTRS_PER_PTE.
2833  *
2834  * The virtual address of the area that we map is naturally aligned to the
2835  * fault_around_pages() value (and therefore to page order).  This way it's
2836  * easier to guarantee that we don't cross page table boundaries.
2837  */
2838 static void do_fault_around(struct vm_area_struct *vma, unsigned long address,
2839                 pte_t *pte, pgoff_t pgoff, unsigned int flags)
2840 {
2841         unsigned long start_addr, nr_pages, mask;
2842         pgoff_t max_pgoff;
2843         struct vm_fault vmf;
2844         int off;
2845 
2846         nr_pages = ACCESS_ONCE(fault_around_bytes) >> PAGE_SHIFT;
2847         mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK;
2848 
2849         start_addr = max(address & mask, vma->vm_start);
2850         off = ((address - start_addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
2851         pte -= off;
2852         pgoff -= off;
2853 
2854         /*
2855          *  max_pgoff is either end of page table or end of vma
2856          *  or fault_around_pages() from pgoff, depending what is nearest.
2857          */
2858         max_pgoff = pgoff - ((start_addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
2859                 PTRS_PER_PTE - 1;
2860         max_pgoff = min3(max_pgoff, vma_pages(vma) + vma->vm_pgoff - 1,
2861                         pgoff + nr_pages - 1);
2862 
2863         /* Check if it makes any sense to call ->map_pages */
2864         while (!pte_none(*pte)) {
2865                 if (++pgoff > max_pgoff)
2866                         return;
2867                 start_addr += PAGE_SIZE;
2868                 if (start_addr >= vma->vm_end)
2869                         return;
2870                 pte++;
2871         }
2872 
2873         vmf.virtual_address = (void __user *) start_addr;
2874         vmf.pte = pte;
2875         vmf.pgoff = pgoff;
2876         vmf.max_pgoff = max_pgoff;
2877         vmf.flags = flags;
2878         vma->vm_ops->map_pages(vma, &vmf);
2879 }
2880 
2881 static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2882                 unsigned long address, pmd_t *pmd,
2883                 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2884 {
2885         struct page *fault_page;
2886         spinlock_t *ptl;
2887         pte_t *pte;
2888         int ret = 0;
2889 
2890         /*
2891          * Let's call ->map_pages() first and use ->fault() as fallback
2892          * if page by the offset is not ready to be mapped (cold cache or
2893          * something).
2894          */
2895         if (vma->vm_ops->map_pages && !(flags & FAULT_FLAG_NONLINEAR) &&
2896             fault_around_bytes >> PAGE_SHIFT > 1) {
2897                 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
2898                 do_fault_around(vma, address, pte, pgoff, flags);
2899                 if (!pte_same(*pte, orig_pte))
2900                         goto unlock_out;
2901                 pte_unmap_unlock(pte, ptl);
2902         }
2903 
2904         ret = __do_fault(vma, address, pgoff, flags, &fault_page);
2905         if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
2906                 return ret;
2907 
2908         pte = pte_offset_map_lock(mm, pmd, address, &ptl);
2909         if (unlikely(!pte_same(*pte, orig_pte))) {
2910                 pte_unmap_unlock(pte, ptl);
2911                 unlock_page(fault_page);
2912                 page_cache_release(fault_page);
2913                 return ret;
2914         }
2915         do_set_pte(vma, address, fault_page, pte, false, false);
2916         unlock_page(fault_page);
2917 unlock_out:
2918         pte_unmap_unlock(pte, ptl);
2919         return ret;
2920 }
2921 
2922 static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2923                 unsigned long address, pmd_t *pmd,
2924                 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2925 {
2926         struct page *fault_page, *new_page;
2927         struct mem_cgroup *memcg;
2928         spinlock_t *ptl;
2929         pte_t *pte;
2930         int ret;
2931 
2932         if (unlikely(anon_vma_prepare(vma)))
2933                 return VM_FAULT_OOM;
2934 
2935         new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2936         if (!new_page)
2937                 return VM_FAULT_OOM;
2938 
2939         if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg)) {
2940                 page_cache_release(new_page);
2941                 return VM_FAULT_OOM;
2942         }
2943 
2944         ret = __do_fault(vma, address, pgoff, flags, &fault_page);
2945         if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
2946                 goto uncharge_out;
2947 
2948         copy_user_highpage(new_page, fault_page, address, vma);
2949         __SetPageUptodate(new_page);
2950 
2951         pte = pte_offset_map_lock(mm, pmd, address, &ptl);
2952         if (unlikely(!pte_same(*pte, orig_pte))) {
2953                 pte_unmap_unlock(pte, ptl);
2954                 unlock_page(fault_page);
2955                 page_cache_release(fault_page);
2956                 goto uncharge_out;
2957         }
2958         do_set_pte(vma, address, new_page, pte, true, true);
2959         mem_cgroup_commit_charge(new_page, memcg, false);
2960         lru_cache_add_active_or_unevictable(new_page, vma);
2961         pte_unmap_unlock(pte, ptl);
2962         unlock_page(fault_page);
2963         page_cache_release(fault_page);
2964         return ret;
2965 uncharge_out:
2966         mem_cgroup_cancel_charge(new_page, memcg);
2967         page_cache_release(new_page);
2968         return ret;
2969 }
2970 
2971 static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2972                 unsigned long address, pmd_t *pmd,
2973                 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2974 {
2975         struct page *fault_page;
2976         struct address_space *mapping;
2977         spinlock_t *ptl;
2978         pte_t *pte;
2979         int dirtied = 0;
2980         int ret, tmp;
2981 
2982         ret = __do_fault(vma, address, pgoff, flags, &fault_page);
2983         if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
2984                 return ret;
2985 
2986         /*
2987          * Check if the backing address space wants to know that the page is
2988          * about to become writable
2989          */
2990         if (vma->vm_ops->page_mkwrite) {
2991                 unlock_page(fault_page);
2992                 tmp = do_page_mkwrite(vma, fault_page, address);
2993                 if (unlikely(!tmp ||
2994                                 (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
2995                         page_cache_release(fault_page);
2996                         return tmp;
2997                 }
2998         }
2999 
3000         pte = pte_offset_map_lock(mm, pmd, address, &ptl);
3001         if (unlikely(!pte_same(*pte, orig_pte))) {
3002                 pte_unmap_unlock(pte, ptl);
3003                 unlock_page(fault_page);
3004                 page_cache_release(fault_page);
3005                 return ret;
3006         }
3007         do_set_pte(vma, address, fault_page, pte, true, false);
3008         pte_unmap_unlock(pte, ptl);
3009 
3010         if (set_page_dirty(fault_page))
3011                 dirtied = 1;
3012         mapping = fault_page->mapping;
3013         unlock_page(fault_page);
3014         if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) {
3015                 /*
3016                  * Some device drivers do not set page.mapping but still
3017                  * dirty their pages
3018                  */
3019                 balance_dirty_pages_ratelimited(mapping);
3020         }
3021 
3022         /* file_update_time outside page_lock */
3023         if (vma->vm_file && !vma->vm_ops->page_mkwrite)
3024                 file_update_time(vma->vm_file);
3025 
3026         return ret;
3027 }
3028 
3029 /*
3030  * We enter with non-exclusive mmap_sem (to exclude vma changes,
3031  * but allow concurrent faults).
3032  * The mmap_sem may have been released depending on flags and our
3033  * return value.  See filemap_fault() and __lock_page_or_retry().
3034  */
3035 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3036                 unsigned long address, pte_t *page_table, pmd_t *pmd,
3037                 unsigned int flags, pte_t orig_pte)
3038 {
3039         pgoff_t pgoff = (((address & PAGE_MASK)
3040                         - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3041 
3042         pte_unmap(page_table);
3043         if (!(flags & FAULT_FLAG_WRITE))
3044                 return do_read_fault(mm, vma, address, pmd, pgoff, flags,
3045                                 orig_pte);
3046         if (!(vma->vm_flags & VM_SHARED))
3047                 return do_cow_fault(mm, vma, address, pmd, pgoff, flags,
3048                                 orig_pte);
3049         return do_shared_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3050 }
3051 
3052 /*
3053  * Fault of a previously existing named mapping. Repopulate the pte
3054  * from the encoded file_pte if possible. This enables swappable
3055  * nonlinear vmas.
3056  *
3057  * We enter with non-exclusive mmap_sem (to exclude vma changes,
3058  * but allow concurrent faults), and pte mapped but not yet locked.
3059  * We return with pte unmapped and unlocked.
3060  * The mmap_sem may have been released depending on flags and our
3061  * return value.  See filemap_fault() and __lock_page_or_retry().
3062  */
3063 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3064                 unsigned long address, pte_t *page_table, pmd_t *pmd,
3065                 unsigned int flags, pte_t orig_pte)
3066 {
3067         pgoff_t pgoff;
3068 
3069         flags |= FAULT_FLAG_NONLINEAR;
3070 
3071         if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3072                 return 0;
3073 
3074         if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3075                 /*
3076                  * Page table corrupted: show pte and kill process.
3077                  */
3078                 print_bad_pte(vma, address, orig_pte, NULL);
3079                 return VM_FAULT_SIGBUS;
3080         }
3081 
3082         pgoff = pte_to_pgoff(orig_pte);
3083         if (!(flags & FAULT_FLAG_WRITE))
3084                 return do_read_fault(mm, vma, address, pmd, pgoff, flags,
3085                                 orig_pte);
3086         if (!(vma->vm_flags & VM_SHARED))
3087                 return do_cow_fault(mm, vma, address, pmd, pgoff, flags,
3088                                 orig_pte);
3089         return do_shared_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3090 }
3091 
3092 static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
3093                                 unsigned long addr, int page_nid,
3094                                 int *flags)
3095 {
3096         get_page(page);
3097 
3098         count_vm_numa_event(NUMA_HINT_FAULTS);
3099         if (page_nid == numa_node_id()) {
3100                 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
3101                 *flags |= TNF_FAULT_LOCAL;
3102         }
3103 
3104         return mpol_misplaced(page, vma, addr);
3105 }
3106 
3107 static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3108                    unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
3109 {
3110         struct page *page = NULL;
3111         spinlock_t *ptl;
3112         int page_nid = -1;
3113         int last_cpupid;
3114         int target_nid;
3115         bool migrated = false;
3116         int flags = 0;
3117 
3118         /*
3119         * The "pte" at this point cannot be used safely without
3120         * validation through pte_unmap_same(). It's of NUMA type but
3121         * the pfn may be screwed if the read is non atomic.
3122         *
3123         * ptep_modify_prot_start is not called as this is clearing
3124         * the _PAGE_NUMA bit and it is not really expected that there
3125         * would be concurrent hardware modifications to the PTE.
3126         */
3127         ptl = pte_lockptr(mm, pmd);
3128         spin_lock(ptl);
3129         if (unlikely(!pte_same(*ptep, pte))) {
3130                 pte_unmap_unlock(ptep, ptl);
3131                 goto out;
3132         }
3133 
3134         pte = pte_mknonnuma(pte);
3135         set_pte_at(mm, addr, ptep, pte);
3136         update_mmu_cache(vma, addr, ptep);
3137 
3138         page = vm_normal_page(vma, addr, pte);
3139         if (!page) {
3140                 pte_unmap_unlock(ptep, ptl);
3141                 return 0;
3142         }
3143         BUG_ON(is_zero_pfn(page_to_pfn(page)));
3144 
3145         /*
3146          * Avoid grouping on DSO/COW pages in specific and RO pages
3147          * in general, RO pages shouldn't hurt as much anyway since
3148          * they can be in shared cache state.
3149          */
3150         if (!pte_write(pte))
3151                 flags |= TNF_NO_GROUP;
3152 
3153         /*
3154          * Flag if the page is shared between multiple address spaces. This
3155          * is later used when determining whether to group tasks together
3156          */
3157         if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED))
3158                 flags |= TNF_SHARED;
3159 
3160         last_cpupid = page_cpupid_last(page);
3161         page_nid = page_to_nid(page);
3162         target_nid = numa_migrate_prep(page, vma, addr, page_nid, &flags);
3163         pte_unmap_unlock(ptep, ptl);
3164         if (target_nid == -1) {
3165                 put_page(page);
3166                 goto out;
3167         }
3168 
3169         /* Migrate to the requested node */
3170         migrated = migrate_misplaced_page(page, vma, target_nid);
3171         if (migrated) {
3172                 page_nid = target_nid;
3173                 flags |= TNF_MIGRATED;
3174         }
3175 
3176 out:
3177         if (page_nid != -1)
3178                 task_numa_fault(last_cpupid, page_nid, 1, flags);
3179         return 0;
3180 }
3181 
3182 /*
3183  * These routines also need to handle stuff like marking pages dirty
3184  * and/or accessed for architectures that don't do it in hardware (most
3185  * RISC architectures).  The early dirtying is also good on the i386.
3186  *
3187  * There is also a hook called "update_mmu_cache()" that architectures
3188  * with external mmu caches can use to update those (ie the Sparc or
3189  * PowerPC hashed page tables that act as extended TLBs).
3190  *
3191  * We enter with non-exclusive mmap_sem (to exclude vma changes,
3192  * but allow concurrent faults), and pte mapped but not yet locked.
3193  * We return with pte unmapped and unlocked.
3194  *
3195  * The mmap_sem may have been released depending on flags and our
3196  * return value.  See filemap_fault() and __lock_page_or_retry().
3197  */
3198 static int handle_pte_fault(struct mm_struct *mm,
3199                      struct vm_area_struct *vma, unsigned long address,
3200                      pte_t *pte, pmd_t *pmd, unsigned int flags)
3201 {
3202         pte_t entry;
3203         spinlock_t *ptl;
3204 
3205         entry = ACCESS_ONCE(*pte);
3206         if (!pte_present(entry)) {
3207                 if (pte_none(entry)) {
3208                         if (vma->vm_ops) {
3209                                 if (likely(vma->vm_ops->fault))
3210                                         return do_linear_fault(mm, vma, address,
3211                                                 pte, pmd, flags, entry);
3212                         }
3213                         return do_anonymous_page(mm, vma, address,
3214                                                  pte, pmd, flags);
3215                 }
3216                 if (pte_file(entry))
3217                         return do_nonlinear_fault(mm, vma, address,
3218                                         pte, pmd, flags, entry);
3219                 return do_swap_page(mm, vma, address,
3220                                         pte, pmd, flags, entry);
3221         }
3222 
3223         if (pte_numa(entry))
3224                 return do_numa_page(mm, vma, address, entry, pte, pmd);
3225 
3226         ptl = pte_lockptr(mm, pmd);
3227         spin_lock(ptl);
3228         if (unlikely(!pte_same(*pte, entry)))
3229                 goto unlock;
3230         if (flags & FAULT_FLAG_WRITE) {
3231                 if (!pte_write(entry))
3232                         return do_wp_page(mm, vma, address,
3233                                         pte, pmd, ptl, entry);
3234                 entry = pte_mkdirty(entry);
3235         }
3236         entry = pte_mkyoung(entry);
3237         if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3238                 update_mmu_cache(vma, address, pte);
3239         } else {
3240                 /*
3241                  * This is needed only for protection faults but the arch code
3242                  * is not yet telling us if this is a protection fault or not.
3243                  * This still avoids useless tlb flushes for .text page faults
3244                  * with threads.
3245                  */
3246                 if (flags & FAULT_FLAG_WRITE)
3247                         flush_tlb_fix_spurious_fault(vma, address);
3248         }
3249 unlock:
3250         pte_unmap_unlock(pte, ptl);
3251         return 0;
3252 }
3253 
3254 /*
3255  * By the time we get here, we already hold the mm semaphore
3256  *
3257  * The mmap_sem may have been released depending on flags and our
3258  * return value.  See filemap_fault() and __lock_page_or_retry().
3259  */
3260 static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3261                              unsigned long address, unsigned int flags)
3262 {
3263         pgd_t *pgd;
3264         pud_t *pud;
3265         pmd_t *pmd;
3266         pte_t *pte;
3267 
3268         if (unlikely(is_vm_hugetlb_page(vma)))
3269                 return hugetlb_fault(mm, vma, address, flags);
3270 
3271         pgd = pgd_offset(mm, address);
3272         pud = pud_alloc(mm, pgd, address);
3273         if (!pud)
3274                 return VM_FAULT_OOM;
3275         pmd = pmd_alloc(mm, pud, address);
3276         if (!pmd)
3277                 return VM_FAULT_OOM;
3278         if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
3279                 int ret = VM_FAULT_FALLBACK;
3280                 if (!vma->vm_ops)
3281                         ret = do_huge_pmd_anonymous_page(mm, vma, address,
3282                                         pmd, flags);
3283                 if (!(ret & VM_FAULT_FALLBACK))
3284                         return ret;
3285         } else {
3286                 pmd_t orig_pmd = *pmd;
3287                 int ret;
3288 
3289                 barrier();
3290                 if (pmd_trans_huge(orig_pmd)) {
3291                         unsigned int dirty = flags & FAULT_FLAG_WRITE;
3292 
3293                         /*
3294                          * If the pmd is splitting, return and retry the
3295                          * the fault.  Alternative: wait until the split
3296                          * is done, and goto retry.
3297                          */
3298                         if (pmd_trans_splitting(orig_pmd))
3299                                 return 0;
3300 
3301                         if (pmd_numa(orig_pmd))
3302                                 return do_huge_pmd_numa_page(mm, vma, address,
3303                                                              orig_pmd, pmd);
3304 
3305                         if (dirty && !pmd_write(orig_pmd)) {
3306                                 ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
3307                                                           orig_pmd);
3308                                 if (!(ret & VM_FAULT_FALLBACK))
3309                                         return ret;
3310                         } else {
3311                                 huge_pmd_set_accessed(mm, vma, address, pmd,
3312                                                       orig_pmd, dirty);
3313                                 return 0;
3314                         }
3315                 }
3316         }
3317 
3318         /*
3319          * Use __pte_alloc instead of pte_alloc_map, because we can't
3320          * run pte_offset_map on the pmd, if an huge pmd could
3321          * materialize from under us from a different thread.
3322          */
3323         if (unlikely(pmd_none(*pmd)) &&
3324             unlikely(__pte_alloc(mm, vma, pmd, address)))
3325                 return VM_FAULT_OOM;
3326         /* if an huge pmd materialized from under us just retry later */
3327         if (unlikely(pmd_trans_huge(*pmd)))
3328                 return 0;
3329         /*
3330          * A regular pmd is established and it can't morph into a huge pmd
3331          * from under us anymore at this point because we hold the mmap_sem
3332          * read mode and khugepaged takes it in write mode. So now it's
3333          * safe to run pte_offset_map().
3334          */
3335         pte = pte_offset_map(pmd, address);
3336 
3337         return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3338 }
3339 
3340 /*
3341  * By the time we get here, we already hold the mm semaphore
3342  *
3343  * The mmap_sem may have been released depending on flags and our
3344  * return value.  See filemap_fault() and __lock_page_or_retry().
3345  */
3346 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3347                     unsigned long address, unsigned int flags)
3348 {
3349         int ret;
3350 
3351         __set_current_state(TASK_RUNNING);
3352 
3353         count_vm_event(PGFAULT);
3354         mem_cgroup_count_vm_event(mm, PGFAULT);
3355 
3356         /* do counter updates before entering really critical section. */
3357         check_sync_rss_stat(current);
3358 
3359         /*
3360          * Enable the memcg OOM handling for faults triggered in user
3361          * space.  Kernel faults are handled more gracefully.
3362          */
3363         if (flags & FAULT_FLAG_USER)
3364                 mem_cgroup_oom_enable();
3365 
3366         ret = __handle_mm_fault(mm, vma, address, flags);
3367 
3368         if (flags & FAULT_FLAG_USER) {
3369                 mem_cgroup_oom_disable();
3370                 /*
3371                  * The task may have entered a memcg OOM situation but
3372                  * if the allocation error was handled gracefully (no
3373                  * VM_FAULT_OOM), there is no need to kill anything.
3374                  * Just clean up the OOM state peacefully.
3375                  */
3376                 if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM))
3377                         mem_cgroup_oom_synchronize(false);
3378         }
3379 
3380         return ret;
3381 }
3382 
3383 #ifndef __PAGETABLE_PUD_FOLDED
3384 /*
3385  * Allocate page upper directory.
3386  * We've already handled the fast-path in-line.
3387  */
3388 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3389 {
3390         pud_t *new = pud_alloc_one(mm, address);
3391         if (!new)
3392                 return -ENOMEM;
3393 
3394         smp_wmb(); /* See comment in __pte_alloc */
3395 
3396         spin_lock(&mm->page_table_lock);
3397         if (pgd_present(*pgd))          /* Another has populated it */
3398                 pud_free(mm, new);
3399         else
3400                 pgd_populate(mm, pgd, new);
3401         spin_unlock(&mm->page_table_lock);
3402         return 0;
3403 }
3404 #endif /* __PAGETABLE_PUD_FOLDED */
3405 
3406 #ifndef __PAGETABLE_PMD_FOLDED
3407 /*
3408  * Allocate page middle directory.
3409  * We've already handled the fast-path in-line.
3410  */
3411 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3412 {
3413         pmd_t *new = pmd_alloc_one(mm, address);
3414         if (!new)
3415                 return -ENOMEM;
3416 
3417         smp_wmb(); /* See comment in __pte_alloc */
3418 
3419         spin_lock(&mm->page_table_lock);
3420 #ifndef __ARCH_HAS_4LEVEL_HACK
3421         if (pud_present(*pud))          /* Another has populated it */
3422                 pmd_free(mm, new);
3423         else
3424                 pud_populate(mm, pud, new);
3425 #else
3426         if (pgd_present(*pud))          /* Another has populated it */
3427                 pmd_free(mm, new);
3428         else
3429                 pgd_populate(mm, pud, new);
3430 #endif /* __ARCH_HAS_4LEVEL_HACK */
3431         spin_unlock(&mm->page_table_lock);
3432         return 0;
3433 }
3434 #endif /* __PAGETABLE_PMD_FOLDED */
3435 
3436 static int __follow_pte(struct mm_struct *mm, unsigned long address,
3437                 pte_t **ptepp, spinlock_t **ptlp)
3438 {
3439         pgd_t *pgd;
3440         pud_t *pud;
3441         pmd_t *pmd;
3442         pte_t *ptep;
3443 
3444         pgd = pgd_offset(mm, address);
3445         if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3446                 goto out;
3447 
3448         pud = pud_offset(pgd, address);
3449         if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3450                 goto out;
3451 
3452         pmd = pmd_offset(pud, address);
3453         VM_BUG_ON(pmd_trans_huge(*pmd));
3454         if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3455                 goto out;
3456 
3457         /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3458         if (pmd_huge(*pmd))
3459                 goto out;
3460 
3461         ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3462         if (!ptep)
3463                 goto out;
3464         if (!pte_present(*ptep))
3465                 goto unlock;
3466         *ptepp = ptep;
3467         return 0;
3468 unlock:
3469         pte_unmap_unlock(ptep, *ptlp);
3470 out:
3471         return -EINVAL;
3472 }
3473 
3474 static inline int follow_pte(struct mm_struct *mm, unsigned long address,
3475                              pte_t **ptepp, spinlock_t **ptlp)
3476 {
3477         int res;
3478 
3479         /* (void) is needed to make gcc happy */
3480         (void) __cond_lock(*ptlp,
3481                            !(res = __follow_pte(mm, address, ptepp, ptlp)));
3482         return res;
3483 }
3484 
3485 /**
3486  * follow_pfn - look up PFN at a user virtual address
3487  * @vma: memory mapping
3488  * @address: user virtual address
3489  * @pfn: location to store found PFN
3490  *
3491  * Only IO mappings and raw PFN mappings are allowed.
3492  *
3493  * Returns zero and the pfn at @pfn on success, -ve otherwise.
3494  */
3495 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3496         unsigned long *pfn)
3497 {
3498         int ret = -EINVAL;
3499         spinlock_t *ptl;
3500         pte_t *ptep;
3501 
3502         if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3503                 return ret;
3504 
3505         ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3506         if (ret)
3507                 return ret;
3508         *pfn = pte_pfn(*ptep);
3509         pte_unmap_unlock(ptep, ptl);
3510         return 0;
3511 }
3512 EXPORT_SYMBOL(follow_pfn);
3513 
3514 #ifdef CONFIG_HAVE_IOREMAP_PROT
3515 int follow_phys(struct vm_area_struct *vma,
3516                 unsigned long address, unsigned int flags,
3517                 unsigned long *prot, resource_size_t *phys)
3518 {
3519         int ret = -EINVAL;
3520         pte_t *ptep, pte;
3521         spinlock_t *ptl;
3522 
3523         if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3524                 goto out;
3525 
3526         if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
3527                 goto out;
3528         pte = *ptep;
3529 
3530         if ((flags & FOLL_WRITE) && !pte_write(pte))
3531                 goto unlock;
3532 
3533         *prot = pgprot_val(pte_pgprot(pte));
3534         *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
3535 
3536         ret = 0;
3537 unlock:
3538         pte_unmap_unlock(ptep, ptl);
3539 out:
3540         return ret;
3541 }
3542 
3543 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3544                         void *buf, int len, int write)
3545 {
3546         resource_size_t phys_addr;
3547         unsigned long prot = 0;
3548         void __iomem *maddr;
3549         int offset = addr & (PAGE_SIZE-1);
3550 
3551         if (follow_phys(vma, addr, write, &prot, &phys_addr))
3552                 return -EINVAL;
3553 
3554         maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3555         if (write)
3556                 memcpy_toio(maddr + offset, buf, len);
3557         else
3558                 memcpy_fromio(buf, maddr + offset, len);
3559         iounmap(maddr);
3560 
3561         return len;
3562 }
3563 EXPORT_SYMBOL_GPL(generic_access_phys);
3564 #endif
3565 
3566 /*
3567  * Access another process' address space as given in mm.  If non-NULL, use the
3568  * given task for page fault accounting.
3569  */
3570 static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
3571                 unsigned long addr, void *buf, int len, int write)
3572 {
3573         struct vm_area_struct *vma;
3574         void *old_buf = buf;
3575 
3576         down_read(&mm->mmap_sem);
3577         /* ignore errors, just check how much was successfully transferred */
3578         while (len) {
3579                 int bytes, ret, offset;
3580                 void *maddr;
3581                 struct page *page = NULL;
3582 
3583                 ret = get_user_pages(tsk, mm, addr, 1,
3584                                 write, 1, &page, &vma);
3585                 if (ret <= 0) {
3586 #ifndef CONFIG_HAVE_IOREMAP_PROT
3587                         break;
3588 #else
3589                         /*
3590                          * Check if this is a VM_IO | VM_PFNMAP VMA, which
3591                          * we can access using slightly different code.
3592                          */
3593                         vma = find_vma(mm, addr);
3594                         if (!vma || vma->vm_start > addr)
3595                                 break;
3596                         if (vma->vm_ops && vma->vm_ops->access)
3597                                 ret = vma->vm_ops->access(vma, addr, buf,
3598                                                           len, write);
3599                         if (ret <= 0)
3600                                 break;
3601                         bytes = ret;
3602 #endif
3603                 } else {
3604                         bytes = len;
3605                         offset = addr & (PAGE_SIZE-1);
3606                         if (bytes > PAGE_SIZE-offset)
3607                                 bytes = PAGE_SIZE-offset;
3608 
3609                         maddr = kmap(page);
3610                         if (write) {
3611                                 copy_to_user_page(vma, page, addr,
3612                                                   maddr + offset, buf, bytes);
3613                                 set_page_dirty_lock(page);
3614                         } else {
3615                                 copy_from_user_page(vma, page, addr,
3616                                                     buf, maddr + offset, bytes);
3617                         }
3618                         kunmap(page);
3619                         page_cache_release(page);
3620                 }
3621                 len -= bytes;
3622                 buf += bytes;
3623                 addr += bytes;
3624         }
3625         up_read(&mm->mmap_sem);
3626 
3627         return buf - old_buf;
3628 }
3629 
3630 /**
3631  * access_remote_vm - access another process' address space
3632  * @mm:         the mm_struct of the target address space
3633  * @addr:       start address to access
3634  * @buf:        source or destination buffer
3635  * @len:        number of bytes to transfer
3636  * @write:      whether the access is a write
3637  *
3638  * The caller must hold a reference on @mm.
3639  */
3640 int access_remote_vm(struct mm_struct *mm, unsigned long addr,
3641                 void *buf, int len, int write)
3642 {
3643         return __access_remote_vm(NULL, mm, addr, buf, len, write);
3644 }
3645 
3646 /*
3647  * Access another process' address space.
3648  * Source/target buffer must be kernel space,
3649  * Do not walk the page table directly, use get_user_pages
3650  */
3651 int access_process_vm(struct task_struct *tsk, unsigned long addr,
3652                 void *buf, int len, int write)
3653 {
3654         struct mm_struct *mm;
3655         int ret;
3656 
3657         mm = get_task_mm(tsk);
3658         if (!mm)
3659                 return 0;
3660 
3661         ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
3662         mmput(mm);
3663 
3664         return ret;
3665 }
3666 
3667 /*
3668  * Print the name of a VMA.
3669  */
3670 void print_vma_addr(char *prefix, unsigned long ip)
3671 {
3672         struct mm_struct *mm = current->mm;
3673         struct vm_area_struct *vma;
3674 
3675         /*
3676          * Do not print if we are in atomic
3677          * contexts (in exception stacks, etc.):
3678          */
3679         if (preempt_count())
3680                 return;
3681 
3682         down_read(&mm->mmap_sem);
3683         vma = find_vma(mm, ip);
3684         if (vma && vma->vm_file) {
3685                 struct file *f = vma->vm_file;
3686                 char *buf = (char *)__get_free_page(GFP_KERNEL);
3687                 if (buf) {
3688                         char *p;
3689 
3690                         p = d_path(&f->f_path, buf, PAGE_SIZE);
3691                         if (IS_ERR(p))
3692                                 p = "?";
3693                         printk("%s%s[%lx+%lx]", prefix, kbasename(p),
3694                                         vma->vm_start,
3695                                         vma->vm_end - vma->vm_start);
3696                         free_page((unsigned long)buf);
3697                 }
3698         }
3699         up_read(&mm->mmap_sem);
3700 }
3701 
3702 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
3703 void might_fault(void)
3704 {
3705         /*
3706          * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3707          * holding the mmap_sem, this is safe because kernel memory doesn't
3708          * get paged out, therefore we'll never actually fault, and the
3709          * below annotations will generate false positives.
3710          */
3711         if (segment_eq(get_fs(), KERNEL_DS))
3712                 return;
3713 
3714         /*
3715          * it would be nicer only to annotate paths which are not under
3716          * pagefault_disable, however that requires a larger audit and
3717          * providing helpers like get_user_atomic.
3718          */
3719         if (in_atomic())
3720                 return;
3721 
3722         __might_sleep(__FILE__, __LINE__, 0);
3723 
3724         if (current->mm)
3725                 might_lock_read(&current->mm->mmap_sem);
3726 }
3727 EXPORT_SYMBOL(might_fault);
3728 #endif
3729 
3730 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
3731 static void clear_gigantic_page(struct page *page,
3732                                 unsigned long addr,
3733                                 unsigned int pages_per_huge_page)
3734 {
3735         int i;
3736         struct page *p = page;
3737 
3738         might_sleep();
3739         for (i = 0; i < pages_per_huge_page;
3740              i++, p = mem_map_next(p, page, i)) {
3741                 cond_resched();
3742                 clear_user_highpage(p, addr + i * PAGE_SIZE);
3743         }
3744 }
3745 void clear_huge_page(struct page *page,
3746                      unsigned long addr, unsigned int pages_per_huge_page)
3747 {
3748         int i;
3749 
3750         if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
3751                 clear_gigantic_page(page, addr, pages_per_huge_page);
3752                 return;
3753         }
3754 
3755         might_sleep();
3756         for (i = 0; i < pages_per_huge_page; i++) {
3757                 cond_resched();
3758                 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
3759         }
3760 }
3761 
3762 static void copy_user_gigantic_page(struct page *dst, struct page *src,
3763                                     unsigned long addr,
3764                                     struct vm_area_struct *vma,
3765                                     unsigned int pages_per_huge_page)
3766 {
3767         int i;
3768         struct page *dst_base = dst;
3769         struct page *src_base = src;
3770 
3771         for (i = 0; i < pages_per_huge_page; ) {
3772                 cond_resched();
3773                 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
3774 
3775                 i++;
3776                 dst = mem_map_next(dst, dst_base, i);
3777                 src = mem_map_next(src, src_base, i);
3778         }
3779 }
3780 
3781 void copy_user_huge_page(struct page *dst, struct page *src,
3782                          unsigned long addr, struct vm_area_struct *vma,
3783                          unsigned int pages_per_huge_page)
3784 {
3785         int i;
3786 
3787         if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
3788                 copy_user_gigantic_page(dst, src, addr, vma,
3789                                         pages_per_huge_page);
3790                 return;
3791         }
3792 
3793         might_sleep();
3794         for (i = 0; i < pages_per_huge_page; i++) {
3795                 cond_resched();
3796                 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
3797         }
3798 }
3799 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
3800 
3801 #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
3802 
3803 static struct kmem_cache *page_ptl_cachep;
3804 
3805 void __init ptlock_cache_init(void)
3806 {
3807         page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,
3808                         SLAB_PANIC, NULL);
3809 }
3810 
3811 bool ptlock_alloc(struct page *page)
3812 {
3813         spinlock_t *ptl;
3814 
3815         ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
3816         if (!ptl)
3817                 return false;
3818         page->ptl = ptl;
3819         return true;
3820 }
3821 
3822 void ptlock_free(struct page *page)
3823 {
3824         kmem_cache_free(page_ptl_cachep, page->ptl);
3825 }
3826 #endif
3827 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us