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Linux/mm/vmalloc.c

  1 /*
  2  *  linux/mm/vmalloc.c
  3  *
  4  *  Copyright (C) 1993  Linus Torvalds
  5  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
  6  *  SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
  7  *  Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
  8  *  Numa awareness, Christoph Lameter, SGI, June 2005
  9  */
 10 
 11 #include <linux/vmalloc.h>
 12 #include <linux/mm.h>
 13 #include <linux/module.h>
 14 #include <linux/highmem.h>
 15 #include <linux/sched.h>
 16 #include <linux/slab.h>
 17 #include <linux/spinlock.h>
 18 #include <linux/interrupt.h>
 19 #include <linux/proc_fs.h>
 20 #include <linux/seq_file.h>
 21 #include <linux/debugobjects.h>
 22 #include <linux/kallsyms.h>
 23 #include <linux/list.h>
 24 #include <linux/notifier.h>
 25 #include <linux/rbtree.h>
 26 #include <linux/radix-tree.h>
 27 #include <linux/rcupdate.h>
 28 #include <linux/pfn.h>
 29 #include <linux/kmemleak.h>
 30 #include <linux/atomic.h>
 31 #include <linux/compiler.h>
 32 #include <linux/llist.h>
 33 #include <linux/bitops.h>
 34 
 35 #include <linux/uaccess.h>
 36 #include <asm/tlbflush.h>
 37 #include <asm/shmparam.h>
 38 
 39 #include "internal.h"
 40 
 41 struct vfree_deferred {
 42         struct llist_head list;
 43         struct work_struct wq;
 44 };
 45 static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
 46 
 47 static void __vunmap(const void *, int);
 48 
 49 static void free_work(struct work_struct *w)
 50 {
 51         struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
 52         struct llist_node *llnode = llist_del_all(&p->list);
 53         while (llnode) {
 54                 void *p = llnode;
 55                 llnode = llist_next(llnode);
 56                 __vunmap(p, 1);
 57         }
 58 }
 59 
 60 /*** Page table manipulation functions ***/
 61 
 62 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
 63 {
 64         pte_t *pte;
 65 
 66         pte = pte_offset_kernel(pmd, addr);
 67         do {
 68                 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
 69                 WARN_ON(!pte_none(ptent) && !pte_present(ptent));
 70         } while (pte++, addr += PAGE_SIZE, addr != end);
 71 }
 72 
 73 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
 74 {
 75         pmd_t *pmd;
 76         unsigned long next;
 77 
 78         pmd = pmd_offset(pud, addr);
 79         do {
 80                 next = pmd_addr_end(addr, end);
 81                 if (pmd_clear_huge(pmd))
 82                         continue;
 83                 if (pmd_none_or_clear_bad(pmd))
 84                         continue;
 85                 vunmap_pte_range(pmd, addr, next);
 86         } while (pmd++, addr = next, addr != end);
 87 }
 88 
 89 static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
 90 {
 91         pud_t *pud;
 92         unsigned long next;
 93 
 94         pud = pud_offset(pgd, addr);
 95         do {
 96                 next = pud_addr_end(addr, end);
 97                 if (pud_clear_huge(pud))
 98                         continue;
 99                 if (pud_none_or_clear_bad(pud))
100                         continue;
101                 vunmap_pmd_range(pud, addr, next);
102         } while (pud++, addr = next, addr != end);
103 }
104 
105 static void vunmap_page_range(unsigned long addr, unsigned long end)
106 {
107         pgd_t *pgd;
108         unsigned long next;
109 
110         BUG_ON(addr >= end);
111         pgd = pgd_offset_k(addr);
112         do {
113                 next = pgd_addr_end(addr, end);
114                 if (pgd_none_or_clear_bad(pgd))
115                         continue;
116                 vunmap_pud_range(pgd, addr, next);
117         } while (pgd++, addr = next, addr != end);
118 }
119 
120 static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
121                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
122 {
123         pte_t *pte;
124 
125         /*
126          * nr is a running index into the array which helps higher level
127          * callers keep track of where we're up to.
128          */
129 
130         pte = pte_alloc_kernel(pmd, addr);
131         if (!pte)
132                 return -ENOMEM;
133         do {
134                 struct page *page = pages[*nr];
135 
136                 if (WARN_ON(!pte_none(*pte)))
137                         return -EBUSY;
138                 if (WARN_ON(!page))
139                         return -ENOMEM;
140                 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
141                 (*nr)++;
142         } while (pte++, addr += PAGE_SIZE, addr != end);
143         return 0;
144 }
145 
146 static int vmap_pmd_range(pud_t *pud, unsigned long addr,
147                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
148 {
149         pmd_t *pmd;
150         unsigned long next;
151 
152         pmd = pmd_alloc(&init_mm, pud, addr);
153         if (!pmd)
154                 return -ENOMEM;
155         do {
156                 next = pmd_addr_end(addr, end);
157                 if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
158                         return -ENOMEM;
159         } while (pmd++, addr = next, addr != end);
160         return 0;
161 }
162 
163 static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
164                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
165 {
166         pud_t *pud;
167         unsigned long next;
168 
169         pud = pud_alloc(&init_mm, pgd, addr);
170         if (!pud)
171                 return -ENOMEM;
172         do {
173                 next = pud_addr_end(addr, end);
174                 if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
175                         return -ENOMEM;
176         } while (pud++, addr = next, addr != end);
177         return 0;
178 }
179 
180 /*
181  * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
182  * will have pfns corresponding to the "pages" array.
183  *
184  * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
185  */
186 static int vmap_page_range_noflush(unsigned long start, unsigned long end,
187                                    pgprot_t prot, struct page **pages)
188 {
189         pgd_t *pgd;
190         unsigned long next;
191         unsigned long addr = start;
192         int err = 0;
193         int nr = 0;
194 
195         BUG_ON(addr >= end);
196         pgd = pgd_offset_k(addr);
197         do {
198                 next = pgd_addr_end(addr, end);
199                 err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
200                 if (err)
201                         return err;
202         } while (pgd++, addr = next, addr != end);
203 
204         return nr;
205 }
206 
207 static int vmap_page_range(unsigned long start, unsigned long end,
208                            pgprot_t prot, struct page **pages)
209 {
210         int ret;
211 
212         ret = vmap_page_range_noflush(start, end, prot, pages);
213         flush_cache_vmap(start, end);
214         return ret;
215 }
216 
217 int is_vmalloc_or_module_addr(const void *x)
218 {
219         /*
220          * ARM, x86-64 and sparc64 put modules in a special place,
221          * and fall back on vmalloc() if that fails. Others
222          * just put it in the vmalloc space.
223          */
224 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
225         unsigned long addr = (unsigned long)x;
226         if (addr >= MODULES_VADDR && addr < MODULES_END)
227                 return 1;
228 #endif
229         return is_vmalloc_addr(x);
230 }
231 
232 /*
233  * Walk a vmap address to the struct page it maps.
234  */
235 struct page *vmalloc_to_page(const void *vmalloc_addr)
236 {
237         unsigned long addr = (unsigned long) vmalloc_addr;
238         struct page *page = NULL;
239         pgd_t *pgd = pgd_offset_k(addr);
240 
241         /*
242          * XXX we might need to change this if we add VIRTUAL_BUG_ON for
243          * architectures that do not vmalloc module space
244          */
245         VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
246 
247         if (!pgd_none(*pgd)) {
248                 pud_t *pud = pud_offset(pgd, addr);
249                 if (!pud_none(*pud)) {
250                         pmd_t *pmd = pmd_offset(pud, addr);
251                         if (!pmd_none(*pmd)) {
252                                 pte_t *ptep, pte;
253 
254                                 ptep = pte_offset_map(pmd, addr);
255                                 pte = *ptep;
256                                 if (pte_present(pte))
257                                         page = pte_page(pte);
258                                 pte_unmap(ptep);
259                         }
260                 }
261         }
262         return page;
263 }
264 EXPORT_SYMBOL(vmalloc_to_page);
265 
266 /*
267  * Map a vmalloc()-space virtual address to the physical page frame number.
268  */
269 unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
270 {
271         return page_to_pfn(vmalloc_to_page(vmalloc_addr));
272 }
273 EXPORT_SYMBOL(vmalloc_to_pfn);
274 
275 
276 /*** Global kva allocator ***/
277 
278 #define VM_VM_AREA      0x04
279 
280 static DEFINE_SPINLOCK(vmap_area_lock);
281 /* Export for kexec only */
282 LIST_HEAD(vmap_area_list);
283 static LLIST_HEAD(vmap_purge_list);
284 static struct rb_root vmap_area_root = RB_ROOT;
285 
286 /* The vmap cache globals are protected by vmap_area_lock */
287 static struct rb_node *free_vmap_cache;
288 static unsigned long cached_hole_size;
289 static unsigned long cached_vstart;
290 static unsigned long cached_align;
291 
292 static unsigned long vmap_area_pcpu_hole;
293 
294 static struct vmap_area *__find_vmap_area(unsigned long addr)
295 {
296         struct rb_node *n = vmap_area_root.rb_node;
297 
298         while (n) {
299                 struct vmap_area *va;
300 
301                 va = rb_entry(n, struct vmap_area, rb_node);
302                 if (addr < va->va_start)
303                         n = n->rb_left;
304                 else if (addr >= va->va_end)
305                         n = n->rb_right;
306                 else
307                         return va;
308         }
309 
310         return NULL;
311 }
312 
313 static void __insert_vmap_area(struct vmap_area *va)
314 {
315         struct rb_node **p = &vmap_area_root.rb_node;
316         struct rb_node *parent = NULL;
317         struct rb_node *tmp;
318 
319         while (*p) {
320                 struct vmap_area *tmp_va;
321 
322                 parent = *p;
323                 tmp_va = rb_entry(parent, struct vmap_area, rb_node);
324                 if (va->va_start < tmp_va->va_end)
325                         p = &(*p)->rb_left;
326                 else if (va->va_end > tmp_va->va_start)
327                         p = &(*p)->rb_right;
328                 else
329                         BUG();
330         }
331 
332         rb_link_node(&va->rb_node, parent, p);
333         rb_insert_color(&va->rb_node, &vmap_area_root);
334 
335         /* address-sort this list */
336         tmp = rb_prev(&va->rb_node);
337         if (tmp) {
338                 struct vmap_area *prev;
339                 prev = rb_entry(tmp, struct vmap_area, rb_node);
340                 list_add_rcu(&va->list, &prev->list);
341         } else
342                 list_add_rcu(&va->list, &vmap_area_list);
343 }
344 
345 static void purge_vmap_area_lazy(void);
346 
347 static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
348 
349 /*
350  * Allocate a region of KVA of the specified size and alignment, within the
351  * vstart and vend.
352  */
353 static struct vmap_area *alloc_vmap_area(unsigned long size,
354                                 unsigned long align,
355                                 unsigned long vstart, unsigned long vend,
356                                 int node, gfp_t gfp_mask)
357 {
358         struct vmap_area *va;
359         struct rb_node *n;
360         unsigned long addr;
361         int purged = 0;
362         struct vmap_area *first;
363 
364         BUG_ON(!size);
365         BUG_ON(offset_in_page(size));
366         BUG_ON(!is_power_of_2(align));
367 
368         might_sleep();
369 
370         va = kmalloc_node(sizeof(struct vmap_area),
371                         gfp_mask & GFP_RECLAIM_MASK, node);
372         if (unlikely(!va))
373                 return ERR_PTR(-ENOMEM);
374 
375         /*
376          * Only scan the relevant parts containing pointers to other objects
377          * to avoid false negatives.
378          */
379         kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK);
380 
381 retry:
382         spin_lock(&vmap_area_lock);
383         /*
384          * Invalidate cache if we have more permissive parameters.
385          * cached_hole_size notes the largest hole noticed _below_
386          * the vmap_area cached in free_vmap_cache: if size fits
387          * into that hole, we want to scan from vstart to reuse
388          * the hole instead of allocating above free_vmap_cache.
389          * Note that __free_vmap_area may update free_vmap_cache
390          * without updating cached_hole_size or cached_align.
391          */
392         if (!free_vmap_cache ||
393                         size < cached_hole_size ||
394                         vstart < cached_vstart ||
395                         align < cached_align) {
396 nocache:
397                 cached_hole_size = 0;
398                 free_vmap_cache = NULL;
399         }
400         /* record if we encounter less permissive parameters */
401         cached_vstart = vstart;
402         cached_align = align;
403 
404         /* find starting point for our search */
405         if (free_vmap_cache) {
406                 first = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
407                 addr = ALIGN(first->va_end, align);
408                 if (addr < vstart)
409                         goto nocache;
410                 if (addr + size < addr)
411                         goto overflow;
412 
413         } else {
414                 addr = ALIGN(vstart, align);
415                 if (addr + size < addr)
416                         goto overflow;
417 
418                 n = vmap_area_root.rb_node;
419                 first = NULL;
420 
421                 while (n) {
422                         struct vmap_area *tmp;
423                         tmp = rb_entry(n, struct vmap_area, rb_node);
424                         if (tmp->va_end >= addr) {
425                                 first = tmp;
426                                 if (tmp->va_start <= addr)
427                                         break;
428                                 n = n->rb_left;
429                         } else
430                                 n = n->rb_right;
431                 }
432 
433                 if (!first)
434                         goto found;
435         }
436 
437         /* from the starting point, walk areas until a suitable hole is found */
438         while (addr + size > first->va_start && addr + size <= vend) {
439                 if (addr + cached_hole_size < first->va_start)
440                         cached_hole_size = first->va_start - addr;
441                 addr = ALIGN(first->va_end, align);
442                 if (addr + size < addr)
443                         goto overflow;
444 
445                 if (list_is_last(&first->list, &vmap_area_list))
446                         goto found;
447 
448                 first = list_next_entry(first, list);
449         }
450 
451 found:
452         if (addr + size > vend)
453                 goto overflow;
454 
455         va->va_start = addr;
456         va->va_end = addr + size;
457         va->flags = 0;
458         __insert_vmap_area(va);
459         free_vmap_cache = &va->rb_node;
460         spin_unlock(&vmap_area_lock);
461 
462         BUG_ON(!IS_ALIGNED(va->va_start, align));
463         BUG_ON(va->va_start < vstart);
464         BUG_ON(va->va_end > vend);
465 
466         return va;
467 
468 overflow:
469         spin_unlock(&vmap_area_lock);
470         if (!purged) {
471                 purge_vmap_area_lazy();
472                 purged = 1;
473                 goto retry;
474         }
475 
476         if (gfpflags_allow_blocking(gfp_mask)) {
477                 unsigned long freed = 0;
478                 blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
479                 if (freed > 0) {
480                         purged = 0;
481                         goto retry;
482                 }
483         }
484 
485         if (printk_ratelimit())
486                 pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
487                         size);
488         kfree(va);
489         return ERR_PTR(-EBUSY);
490 }
491 
492 int register_vmap_purge_notifier(struct notifier_block *nb)
493 {
494         return blocking_notifier_chain_register(&vmap_notify_list, nb);
495 }
496 EXPORT_SYMBOL_GPL(register_vmap_purge_notifier);
497 
498 int unregister_vmap_purge_notifier(struct notifier_block *nb)
499 {
500         return blocking_notifier_chain_unregister(&vmap_notify_list, nb);
501 }
502 EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
503 
504 static void __free_vmap_area(struct vmap_area *va)
505 {
506         BUG_ON(RB_EMPTY_NODE(&va->rb_node));
507 
508         if (free_vmap_cache) {
509                 if (va->va_end < cached_vstart) {
510                         free_vmap_cache = NULL;
511                 } else {
512                         struct vmap_area *cache;
513                         cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
514                         if (va->va_start <= cache->va_start) {
515                                 free_vmap_cache = rb_prev(&va->rb_node);
516                                 /*
517                                  * We don't try to update cached_hole_size or
518                                  * cached_align, but it won't go very wrong.
519                                  */
520                         }
521                 }
522         }
523         rb_erase(&va->rb_node, &vmap_area_root);
524         RB_CLEAR_NODE(&va->rb_node);
525         list_del_rcu(&va->list);
526 
527         /*
528          * Track the highest possible candidate for pcpu area
529          * allocation.  Areas outside of vmalloc area can be returned
530          * here too, consider only end addresses which fall inside
531          * vmalloc area proper.
532          */
533         if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
534                 vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
535 
536         kfree_rcu(va, rcu_head);
537 }
538 
539 /*
540  * Free a region of KVA allocated by alloc_vmap_area
541  */
542 static void free_vmap_area(struct vmap_area *va)
543 {
544         spin_lock(&vmap_area_lock);
545         __free_vmap_area(va);
546         spin_unlock(&vmap_area_lock);
547 }
548 
549 /*
550  * Clear the pagetable entries of a given vmap_area
551  */
552 static void unmap_vmap_area(struct vmap_area *va)
553 {
554         vunmap_page_range(va->va_start, va->va_end);
555 }
556 
557 static void vmap_debug_free_range(unsigned long start, unsigned long end)
558 {
559         /*
560          * Unmap page tables and force a TLB flush immediately if pagealloc
561          * debugging is enabled.  This catches use after free bugs similarly to
562          * those in linear kernel virtual address space after a page has been
563          * freed.
564          *
565          * All the lazy freeing logic is still retained, in order to minimise
566          * intrusiveness of this debugging feature.
567          *
568          * This is going to be *slow* (linear kernel virtual address debugging
569          * doesn't do a broadcast TLB flush so it is a lot faster).
570          */
571         if (debug_pagealloc_enabled()) {
572                 vunmap_page_range(start, end);
573                 flush_tlb_kernel_range(start, end);
574         }
575 }
576 
577 /*
578  * lazy_max_pages is the maximum amount of virtual address space we gather up
579  * before attempting to purge with a TLB flush.
580  *
581  * There is a tradeoff here: a larger number will cover more kernel page tables
582  * and take slightly longer to purge, but it will linearly reduce the number of
583  * global TLB flushes that must be performed. It would seem natural to scale
584  * this number up linearly with the number of CPUs (because vmapping activity
585  * could also scale linearly with the number of CPUs), however it is likely
586  * that in practice, workloads might be constrained in other ways that mean
587  * vmap activity will not scale linearly with CPUs. Also, I want to be
588  * conservative and not introduce a big latency on huge systems, so go with
589  * a less aggressive log scale. It will still be an improvement over the old
590  * code, and it will be simple to change the scale factor if we find that it
591  * becomes a problem on bigger systems.
592  */
593 static unsigned long lazy_max_pages(void)
594 {
595         unsigned int log;
596 
597         log = fls(num_online_cpus());
598 
599         return log * (32UL * 1024 * 1024 / PAGE_SIZE);
600 }
601 
602 static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
603 
604 /*
605  * Serialize vmap purging.  There is no actual criticial section protected
606  * by this look, but we want to avoid concurrent calls for performance
607  * reasons and to make the pcpu_get_vm_areas more deterministic.
608  */
609 static DEFINE_MUTEX(vmap_purge_lock);
610 
611 /* for per-CPU blocks */
612 static void purge_fragmented_blocks_allcpus(void);
613 
614 /*
615  * called before a call to iounmap() if the caller wants vm_area_struct's
616  * immediately freed.
617  */
618 void set_iounmap_nonlazy(void)
619 {
620         atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
621 }
622 
623 /*
624  * Purges all lazily-freed vmap areas.
625  */
626 static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
627 {
628         struct llist_node *valist;
629         struct vmap_area *va;
630         struct vmap_area *n_va;
631         bool do_free = false;
632 
633         lockdep_assert_held(&vmap_purge_lock);
634 
635         valist = llist_del_all(&vmap_purge_list);
636         llist_for_each_entry(va, valist, purge_list) {
637                 if (va->va_start < start)
638                         start = va->va_start;
639                 if (va->va_end > end)
640                         end = va->va_end;
641                 do_free = true;
642         }
643 
644         if (!do_free)
645                 return false;
646 
647         flush_tlb_kernel_range(start, end);
648 
649         spin_lock(&vmap_area_lock);
650         llist_for_each_entry_safe(va, n_va, valist, purge_list) {
651                 int nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
652 
653                 __free_vmap_area(va);
654                 atomic_sub(nr, &vmap_lazy_nr);
655                 cond_resched_lock(&vmap_area_lock);
656         }
657         spin_unlock(&vmap_area_lock);
658         return true;
659 }
660 
661 /*
662  * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
663  * is already purging.
664  */
665 static void try_purge_vmap_area_lazy(void)
666 {
667         if (mutex_trylock(&vmap_purge_lock)) {
668                 __purge_vmap_area_lazy(ULONG_MAX, 0);
669                 mutex_unlock(&vmap_purge_lock);
670         }
671 }
672 
673 /*
674  * Kick off a purge of the outstanding lazy areas.
675  */
676 static void purge_vmap_area_lazy(void)
677 {
678         mutex_lock(&vmap_purge_lock);
679         purge_fragmented_blocks_allcpus();
680         __purge_vmap_area_lazy(ULONG_MAX, 0);
681         mutex_unlock(&vmap_purge_lock);
682 }
683 
684 /*
685  * Free a vmap area, caller ensuring that the area has been unmapped
686  * and flush_cache_vunmap had been called for the correct range
687  * previously.
688  */
689 static void free_vmap_area_noflush(struct vmap_area *va)
690 {
691         int nr_lazy;
692 
693         nr_lazy = atomic_add_return((va->va_end - va->va_start) >> PAGE_SHIFT,
694                                     &vmap_lazy_nr);
695 
696         /* After this point, we may free va at any time */
697         llist_add(&va->purge_list, &vmap_purge_list);
698 
699         if (unlikely(nr_lazy > lazy_max_pages()))
700                 try_purge_vmap_area_lazy();
701 }
702 
703 /*
704  * Free and unmap a vmap area
705  */
706 static void free_unmap_vmap_area(struct vmap_area *va)
707 {
708         flush_cache_vunmap(va->va_start, va->va_end);
709         unmap_vmap_area(va);
710         free_vmap_area_noflush(va);
711 }
712 
713 static struct vmap_area *find_vmap_area(unsigned long addr)
714 {
715         struct vmap_area *va;
716 
717         spin_lock(&vmap_area_lock);
718         va = __find_vmap_area(addr);
719         spin_unlock(&vmap_area_lock);
720 
721         return va;
722 }
723 
724 /*** Per cpu kva allocator ***/
725 
726 /*
727  * vmap space is limited especially on 32 bit architectures. Ensure there is
728  * room for at least 16 percpu vmap blocks per CPU.
729  */
730 /*
731  * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
732  * to #define VMALLOC_SPACE             (VMALLOC_END-VMALLOC_START). Guess
733  * instead (we just need a rough idea)
734  */
735 #if BITS_PER_LONG == 32
736 #define VMALLOC_SPACE           (128UL*1024*1024)
737 #else
738 #define VMALLOC_SPACE           (128UL*1024*1024*1024)
739 #endif
740 
741 #define VMALLOC_PAGES           (VMALLOC_SPACE / PAGE_SIZE)
742 #define VMAP_MAX_ALLOC          BITS_PER_LONG   /* 256K with 4K pages */
743 #define VMAP_BBMAP_BITS_MAX     1024    /* 4MB with 4K pages */
744 #define VMAP_BBMAP_BITS_MIN     (VMAP_MAX_ALLOC*2)
745 #define VMAP_MIN(x, y)          ((x) < (y) ? (x) : (y)) /* can't use min() */
746 #define VMAP_MAX(x, y)          ((x) > (y) ? (x) : (y)) /* can't use max() */
747 #define VMAP_BBMAP_BITS         \
748                 VMAP_MIN(VMAP_BBMAP_BITS_MAX,   \
749                 VMAP_MAX(VMAP_BBMAP_BITS_MIN,   \
750                         VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
751 
752 #define VMAP_BLOCK_SIZE         (VMAP_BBMAP_BITS * PAGE_SIZE)
753 
754 static bool vmap_initialized __read_mostly = false;
755 
756 struct vmap_block_queue {
757         spinlock_t lock;
758         struct list_head free;
759 };
760 
761 struct vmap_block {
762         spinlock_t lock;
763         struct vmap_area *va;
764         unsigned long free, dirty;
765         unsigned long dirty_min, dirty_max; /*< dirty range */
766         struct list_head free_list;
767         struct rcu_head rcu_head;
768         struct list_head purge;
769 };
770 
771 /* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
772 static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
773 
774 /*
775  * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
776  * in the free path. Could get rid of this if we change the API to return a
777  * "cookie" from alloc, to be passed to free. But no big deal yet.
778  */
779 static DEFINE_SPINLOCK(vmap_block_tree_lock);
780 static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
781 
782 /*
783  * We should probably have a fallback mechanism to allocate virtual memory
784  * out of partially filled vmap blocks. However vmap block sizing should be
785  * fairly reasonable according to the vmalloc size, so it shouldn't be a
786  * big problem.
787  */
788 
789 static unsigned long addr_to_vb_idx(unsigned long addr)
790 {
791         addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
792         addr /= VMAP_BLOCK_SIZE;
793         return addr;
794 }
795 
796 static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
797 {
798         unsigned long addr;
799 
800         addr = va_start + (pages_off << PAGE_SHIFT);
801         BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start));
802         return (void *)addr;
803 }
804 
805 /**
806  * new_vmap_block - allocates new vmap_block and occupies 2^order pages in this
807  *                  block. Of course pages number can't exceed VMAP_BBMAP_BITS
808  * @order:    how many 2^order pages should be occupied in newly allocated block
809  * @gfp_mask: flags for the page level allocator
810  *
811  * Returns: virtual address in a newly allocated block or ERR_PTR(-errno)
812  */
813 static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
814 {
815         struct vmap_block_queue *vbq;
816         struct vmap_block *vb;
817         struct vmap_area *va;
818         unsigned long vb_idx;
819         int node, err;
820         void *vaddr;
821 
822         node = numa_node_id();
823 
824         vb = kmalloc_node(sizeof(struct vmap_block),
825                         gfp_mask & GFP_RECLAIM_MASK, node);
826         if (unlikely(!vb))
827                 return ERR_PTR(-ENOMEM);
828 
829         va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
830                                         VMALLOC_START, VMALLOC_END,
831                                         node, gfp_mask);
832         if (IS_ERR(va)) {
833                 kfree(vb);
834                 return ERR_CAST(va);
835         }
836 
837         err = radix_tree_preload(gfp_mask);
838         if (unlikely(err)) {
839                 kfree(vb);
840                 free_vmap_area(va);
841                 return ERR_PTR(err);
842         }
843 
844         vaddr = vmap_block_vaddr(va->va_start, 0);
845         spin_lock_init(&vb->lock);
846         vb->va = va;
847         /* At least something should be left free */
848         BUG_ON(VMAP_BBMAP_BITS <= (1UL << order));
849         vb->free = VMAP_BBMAP_BITS - (1UL << order);
850         vb->dirty = 0;
851         vb->dirty_min = VMAP_BBMAP_BITS;
852         vb->dirty_max = 0;
853         INIT_LIST_HEAD(&vb->free_list);
854 
855         vb_idx = addr_to_vb_idx(va->va_start);
856         spin_lock(&vmap_block_tree_lock);
857         err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
858         spin_unlock(&vmap_block_tree_lock);
859         BUG_ON(err);
860         radix_tree_preload_end();
861 
862         vbq = &get_cpu_var(vmap_block_queue);
863         spin_lock(&vbq->lock);
864         list_add_tail_rcu(&vb->free_list, &vbq->free);
865         spin_unlock(&vbq->lock);
866         put_cpu_var(vmap_block_queue);
867 
868         return vaddr;
869 }
870 
871 static void free_vmap_block(struct vmap_block *vb)
872 {
873         struct vmap_block *tmp;
874         unsigned long vb_idx;
875 
876         vb_idx = addr_to_vb_idx(vb->va->va_start);
877         spin_lock(&vmap_block_tree_lock);
878         tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
879         spin_unlock(&vmap_block_tree_lock);
880         BUG_ON(tmp != vb);
881 
882         free_vmap_area_noflush(vb->va);
883         kfree_rcu(vb, rcu_head);
884 }
885 
886 static void purge_fragmented_blocks(int cpu)
887 {
888         LIST_HEAD(purge);
889         struct vmap_block *vb;
890         struct vmap_block *n_vb;
891         struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
892 
893         rcu_read_lock();
894         list_for_each_entry_rcu(vb, &vbq->free, free_list) {
895 
896                 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
897                         continue;
898 
899                 spin_lock(&vb->lock);
900                 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
901                         vb->free = 0; /* prevent further allocs after releasing lock */
902                         vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
903                         vb->dirty_min = 0;
904                         vb->dirty_max = VMAP_BBMAP_BITS;
905                         spin_lock(&vbq->lock);
906                         list_del_rcu(&vb->free_list);
907                         spin_unlock(&vbq->lock);
908                         spin_unlock(&vb->lock);
909                         list_add_tail(&vb->purge, &purge);
910                 } else
911                         spin_unlock(&vb->lock);
912         }
913         rcu_read_unlock();
914 
915         list_for_each_entry_safe(vb, n_vb, &purge, purge) {
916                 list_del(&vb->purge);
917                 free_vmap_block(vb);
918         }
919 }
920 
921 static void purge_fragmented_blocks_allcpus(void)
922 {
923         int cpu;
924 
925         for_each_possible_cpu(cpu)
926                 purge_fragmented_blocks(cpu);
927 }
928 
929 static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
930 {
931         struct vmap_block_queue *vbq;
932         struct vmap_block *vb;
933         void *vaddr = NULL;
934         unsigned int order;
935 
936         BUG_ON(offset_in_page(size));
937         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
938         if (WARN_ON(size == 0)) {
939                 /*
940                  * Allocating 0 bytes isn't what caller wants since
941                  * get_order(0) returns funny result. Just warn and terminate
942                  * early.
943                  */
944                 return NULL;
945         }
946         order = get_order(size);
947 
948         rcu_read_lock();
949         vbq = &get_cpu_var(vmap_block_queue);
950         list_for_each_entry_rcu(vb, &vbq->free, free_list) {
951                 unsigned long pages_off;
952 
953                 spin_lock(&vb->lock);
954                 if (vb->free < (1UL << order)) {
955                         spin_unlock(&vb->lock);
956                         continue;
957                 }
958 
959                 pages_off = VMAP_BBMAP_BITS - vb->free;
960                 vaddr = vmap_block_vaddr(vb->va->va_start, pages_off);
961                 vb->free -= 1UL << order;
962                 if (vb->free == 0) {
963                         spin_lock(&vbq->lock);
964                         list_del_rcu(&vb->free_list);
965                         spin_unlock(&vbq->lock);
966                 }
967 
968                 spin_unlock(&vb->lock);
969                 break;
970         }
971 
972         put_cpu_var(vmap_block_queue);
973         rcu_read_unlock();
974 
975         /* Allocate new block if nothing was found */
976         if (!vaddr)
977                 vaddr = new_vmap_block(order, gfp_mask);
978 
979         return vaddr;
980 }
981 
982 static void vb_free(const void *addr, unsigned long size)
983 {
984         unsigned long offset;
985         unsigned long vb_idx;
986         unsigned int order;
987         struct vmap_block *vb;
988 
989         BUG_ON(offset_in_page(size));
990         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
991 
992         flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
993 
994         order = get_order(size);
995 
996         offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
997         offset >>= PAGE_SHIFT;
998 
999         vb_idx = addr_to_vb_idx((unsigned long)addr);
1000         rcu_read_lock();
1001         vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
1002         rcu_read_unlock();
1003         BUG_ON(!vb);
1004 
1005         vunmap_page_range((unsigned long)addr, (unsigned long)addr + size);
1006 
1007         spin_lock(&vb->lock);
1008 
1009         /* Expand dirty range */
1010         vb->dirty_min = min(vb->dirty_min, offset);
1011         vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
1012 
1013         vb->dirty += 1UL << order;
1014         if (vb->dirty == VMAP_BBMAP_BITS) {
1015                 BUG_ON(vb->free);
1016                 spin_unlock(&vb->lock);
1017                 free_vmap_block(vb);
1018         } else
1019                 spin_unlock(&vb->lock);
1020 }
1021 
1022 /**
1023  * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
1024  *
1025  * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
1026  * to amortize TLB flushing overheads. What this means is that any page you
1027  * have now, may, in a former life, have been mapped into kernel virtual
1028  * address by the vmap layer and so there might be some CPUs with TLB entries
1029  * still referencing that page (additional to the regular 1:1 kernel mapping).
1030  *
1031  * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
1032  * be sure that none of the pages we have control over will have any aliases
1033  * from the vmap layer.
1034  */
1035 void vm_unmap_aliases(void)
1036 {
1037         unsigned long start = ULONG_MAX, end = 0;
1038         int cpu;
1039         int flush = 0;
1040 
1041         if (unlikely(!vmap_initialized))
1042                 return;
1043 
1044         might_sleep();
1045 
1046         for_each_possible_cpu(cpu) {
1047                 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1048                 struct vmap_block *vb;
1049 
1050                 rcu_read_lock();
1051                 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1052                         spin_lock(&vb->lock);
1053                         if (vb->dirty) {
1054                                 unsigned long va_start = vb->va->va_start;
1055                                 unsigned long s, e;
1056 
1057                                 s = va_start + (vb->dirty_min << PAGE_SHIFT);
1058                                 e = va_start + (vb->dirty_max << PAGE_SHIFT);
1059 
1060                                 start = min(s, start);
1061                                 end   = max(e, end);
1062 
1063                                 flush = 1;
1064                         }
1065                         spin_unlock(&vb->lock);
1066                 }
1067                 rcu_read_unlock();
1068         }
1069 
1070         mutex_lock(&vmap_purge_lock);
1071         purge_fragmented_blocks_allcpus();
1072         if (!__purge_vmap_area_lazy(start, end) && flush)
1073                 flush_tlb_kernel_range(start, end);
1074         mutex_unlock(&vmap_purge_lock);
1075 }
1076 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
1077 
1078 /**
1079  * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
1080  * @mem: the pointer returned by vm_map_ram
1081  * @count: the count passed to that vm_map_ram call (cannot unmap partial)
1082  */
1083 void vm_unmap_ram(const void *mem, unsigned int count)
1084 {
1085         unsigned long size = (unsigned long)count << PAGE_SHIFT;
1086         unsigned long addr = (unsigned long)mem;
1087         struct vmap_area *va;
1088 
1089         might_sleep();
1090         BUG_ON(!addr);
1091         BUG_ON(addr < VMALLOC_START);
1092         BUG_ON(addr > VMALLOC_END);
1093         BUG_ON(!PAGE_ALIGNED(addr));
1094 
1095         debug_check_no_locks_freed(mem, size);
1096         vmap_debug_free_range(addr, addr+size);
1097 
1098         if (likely(count <= VMAP_MAX_ALLOC)) {
1099                 vb_free(mem, size);
1100                 return;
1101         }
1102 
1103         va = find_vmap_area(addr);
1104         BUG_ON(!va);
1105         free_unmap_vmap_area(va);
1106 }
1107 EXPORT_SYMBOL(vm_unmap_ram);
1108 
1109 /**
1110  * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
1111  * @pages: an array of pointers to the pages to be mapped
1112  * @count: number of pages
1113  * @node: prefer to allocate data structures on this node
1114  * @prot: memory protection to use. PAGE_KERNEL for regular RAM
1115  *
1116  * If you use this function for less than VMAP_MAX_ALLOC pages, it could be
1117  * faster than vmap so it's good.  But if you mix long-life and short-life
1118  * objects with vm_map_ram(), it could consume lots of address space through
1119  * fragmentation (especially on a 32bit machine).  You could see failures in
1120  * the end.  Please use this function for short-lived objects.
1121  *
1122  * Returns: a pointer to the address that has been mapped, or %NULL on failure
1123  */
1124 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
1125 {
1126         unsigned long size = (unsigned long)count << PAGE_SHIFT;
1127         unsigned long addr;
1128         void *mem;
1129 
1130         if (likely(count <= VMAP_MAX_ALLOC)) {
1131                 mem = vb_alloc(size, GFP_KERNEL);
1132                 if (IS_ERR(mem))
1133                         return NULL;
1134                 addr = (unsigned long)mem;
1135         } else {
1136                 struct vmap_area *va;
1137                 va = alloc_vmap_area(size, PAGE_SIZE,
1138                                 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1139                 if (IS_ERR(va))
1140                         return NULL;
1141 
1142                 addr = va->va_start;
1143                 mem = (void *)addr;
1144         }
1145         if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
1146                 vm_unmap_ram(mem, count);
1147                 return NULL;
1148         }
1149         return mem;
1150 }
1151 EXPORT_SYMBOL(vm_map_ram);
1152 
1153 static struct vm_struct *vmlist __initdata;
1154 /**
1155  * vm_area_add_early - add vmap area early during boot
1156  * @vm: vm_struct to add
1157  *
1158  * This function is used to add fixed kernel vm area to vmlist before
1159  * vmalloc_init() is called.  @vm->addr, @vm->size, and @vm->flags
1160  * should contain proper values and the other fields should be zero.
1161  *
1162  * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1163  */
1164 void __init vm_area_add_early(struct vm_struct *vm)
1165 {
1166         struct vm_struct *tmp, **p;
1167 
1168         BUG_ON(vmap_initialized);
1169         for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1170                 if (tmp->addr >= vm->addr) {
1171                         BUG_ON(tmp->addr < vm->addr + vm->size);
1172                         break;
1173                 } else
1174                         BUG_ON(tmp->addr + tmp->size > vm->addr);
1175         }
1176         vm->next = *p;
1177         *p = vm;
1178 }
1179 
1180 /**
1181  * vm_area_register_early - register vmap area early during boot
1182  * @vm: vm_struct to register
1183  * @align: requested alignment
1184  *
1185  * This function is used to register kernel vm area before
1186  * vmalloc_init() is called.  @vm->size and @vm->flags should contain
1187  * proper values on entry and other fields should be zero.  On return,
1188  * vm->addr contains the allocated address.
1189  *
1190  * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1191  */
1192 void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1193 {
1194         static size_t vm_init_off __initdata;
1195         unsigned long addr;
1196 
1197         addr = ALIGN(VMALLOC_START + vm_init_off, align);
1198         vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1199 
1200         vm->addr = (void *)addr;
1201 
1202         vm_area_add_early(vm);
1203 }
1204 
1205 void __init vmalloc_init(void)
1206 {
1207         struct vmap_area *va;
1208         struct vm_struct *tmp;
1209         int i;
1210 
1211         for_each_possible_cpu(i) {
1212                 struct vmap_block_queue *vbq;
1213                 struct vfree_deferred *p;
1214 
1215                 vbq = &per_cpu(vmap_block_queue, i);
1216                 spin_lock_init(&vbq->lock);
1217                 INIT_LIST_HEAD(&vbq->free);
1218                 p = &per_cpu(vfree_deferred, i);
1219                 init_llist_head(&p->list);
1220                 INIT_WORK(&p->wq, free_work);
1221         }
1222 
1223         /* Import existing vmlist entries. */
1224         for (tmp = vmlist; tmp; tmp = tmp->next) {
1225                 va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
1226                 va->flags = VM_VM_AREA;
1227                 va->va_start = (unsigned long)tmp->addr;
1228                 va->va_end = va->va_start + tmp->size;
1229                 va->vm = tmp;
1230                 __insert_vmap_area(va);
1231         }
1232 
1233         vmap_area_pcpu_hole = VMALLOC_END;
1234 
1235         vmap_initialized = true;
1236 }
1237 
1238 /**
1239  * map_kernel_range_noflush - map kernel VM area with the specified pages
1240  * @addr: start of the VM area to map
1241  * @size: size of the VM area to map
1242  * @prot: page protection flags to use
1243  * @pages: pages to map
1244  *
1245  * Map PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1246  * specify should have been allocated using get_vm_area() and its
1247  * friends.
1248  *
1249  * NOTE:
1250  * This function does NOT do any cache flushing.  The caller is
1251  * responsible for calling flush_cache_vmap() on to-be-mapped areas
1252  * before calling this function.
1253  *
1254  * RETURNS:
1255  * The number of pages mapped on success, -errno on failure.
1256  */
1257 int map_kernel_range_noflush(unsigned long addr, unsigned long size,
1258                              pgprot_t prot, struct page **pages)
1259 {
1260         return vmap_page_range_noflush(addr, addr + size, prot, pages);
1261 }
1262 
1263 /**
1264  * unmap_kernel_range_noflush - unmap kernel VM area
1265  * @addr: start of the VM area to unmap
1266  * @size: size of the VM area to unmap
1267  *
1268  * Unmap PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1269  * specify should have been allocated using get_vm_area() and its
1270  * friends.
1271  *
1272  * NOTE:
1273  * This function does NOT do any cache flushing.  The caller is
1274  * responsible for calling flush_cache_vunmap() on to-be-mapped areas
1275  * before calling this function and flush_tlb_kernel_range() after.
1276  */
1277 void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
1278 {
1279         vunmap_page_range(addr, addr + size);
1280 }
1281 EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush);
1282 
1283 /**
1284  * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
1285  * @addr: start of the VM area to unmap
1286  * @size: size of the VM area to unmap
1287  *
1288  * Similar to unmap_kernel_range_noflush() but flushes vcache before
1289  * the unmapping and tlb after.
1290  */
1291 void unmap_kernel_range(unsigned long addr, unsigned long size)
1292 {
1293         unsigned long end = addr + size;
1294 
1295         flush_cache_vunmap(addr, end);
1296         vunmap_page_range(addr, end);
1297         flush_tlb_kernel_range(addr, end);
1298 }
1299 EXPORT_SYMBOL_GPL(unmap_kernel_range);
1300 
1301 int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages)
1302 {
1303         unsigned long addr = (unsigned long)area->addr;
1304         unsigned long end = addr + get_vm_area_size(area);
1305         int err;
1306 
1307         err = vmap_page_range(addr, end, prot, pages);
1308 
1309         return err > 0 ? 0 : err;
1310 }
1311 EXPORT_SYMBOL_GPL(map_vm_area);
1312 
1313 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1314                               unsigned long flags, const void *caller)
1315 {
1316         spin_lock(&vmap_area_lock);
1317         vm->flags = flags;
1318         vm->addr = (void *)va->va_start;
1319         vm->size = va->va_end - va->va_start;
1320         vm->caller = caller;
1321         va->vm = vm;
1322         va->flags |= VM_VM_AREA;
1323         spin_unlock(&vmap_area_lock);
1324 }
1325 
1326 static void clear_vm_uninitialized_flag(struct vm_struct *vm)
1327 {
1328         /*
1329          * Before removing VM_UNINITIALIZED,
1330          * we should make sure that vm has proper values.
1331          * Pair with smp_rmb() in show_numa_info().
1332          */
1333         smp_wmb();
1334         vm->flags &= ~VM_UNINITIALIZED;
1335 }
1336 
1337 static struct vm_struct *__get_vm_area_node(unsigned long size,
1338                 unsigned long align, unsigned long flags, unsigned long start,
1339                 unsigned long end, int node, gfp_t gfp_mask, const void *caller)
1340 {
1341         struct vmap_area *va;
1342         struct vm_struct *area;
1343 
1344         BUG_ON(in_interrupt());
1345         size = PAGE_ALIGN(size);
1346         if (unlikely(!size))
1347                 return NULL;
1348 
1349         if (flags & VM_IOREMAP)
1350                 align = 1ul << clamp_t(int, get_count_order_long(size),
1351                                        PAGE_SHIFT, IOREMAP_MAX_ORDER);
1352 
1353         area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
1354         if (unlikely(!area))
1355                 return NULL;
1356 
1357         if (!(flags & VM_NO_GUARD))
1358                 size += PAGE_SIZE;
1359 
1360         va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
1361         if (IS_ERR(va)) {
1362                 kfree(area);
1363                 return NULL;
1364         }
1365 
1366         setup_vmalloc_vm(area, va, flags, caller);
1367 
1368         return area;
1369 }
1370 
1371 struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
1372                                 unsigned long start, unsigned long end)
1373 {
1374         return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1375                                   GFP_KERNEL, __builtin_return_address(0));
1376 }
1377 EXPORT_SYMBOL_GPL(__get_vm_area);
1378 
1379 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
1380                                        unsigned long start, unsigned long end,
1381                                        const void *caller)
1382 {
1383         return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1384                                   GFP_KERNEL, caller);
1385 }
1386 
1387 /**
1388  *      get_vm_area  -  reserve a contiguous kernel virtual area
1389  *      @size:          size of the area
1390  *      @flags:         %VM_IOREMAP for I/O mappings or VM_ALLOC
1391  *
1392  *      Search an area of @size in the kernel virtual mapping area,
1393  *      and reserved it for out purposes.  Returns the area descriptor
1394  *      on success or %NULL on failure.
1395  */
1396 struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
1397 {
1398         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1399                                   NUMA_NO_NODE, GFP_KERNEL,
1400                                   __builtin_return_address(0));
1401 }
1402 
1403 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
1404                                 const void *caller)
1405 {
1406         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1407                                   NUMA_NO_NODE, GFP_KERNEL, caller);
1408 }
1409 
1410 /**
1411  *      find_vm_area  -  find a continuous kernel virtual area
1412  *      @addr:          base address
1413  *
1414  *      Search for the kernel VM area starting at @addr, and return it.
1415  *      It is up to the caller to do all required locking to keep the returned
1416  *      pointer valid.
1417  */
1418 struct vm_struct *find_vm_area(const void *addr)
1419 {
1420         struct vmap_area *va;
1421 
1422         va = find_vmap_area((unsigned long)addr);
1423         if (va && va->flags & VM_VM_AREA)
1424                 return va->vm;
1425 
1426         return NULL;
1427 }
1428 
1429 /**
1430  *      remove_vm_area  -  find and remove a continuous kernel virtual area
1431  *      @addr:          base address
1432  *
1433  *      Search for the kernel VM area starting at @addr, and remove it.
1434  *      This function returns the found VM area, but using it is NOT safe
1435  *      on SMP machines, except for its size or flags.
1436  */
1437 struct vm_struct *remove_vm_area(const void *addr)
1438 {
1439         struct vmap_area *va;
1440 
1441         might_sleep();
1442 
1443         va = find_vmap_area((unsigned long)addr);
1444         if (va && va->flags & VM_VM_AREA) {
1445                 struct vm_struct *vm = va->vm;
1446 
1447                 spin_lock(&vmap_area_lock);
1448                 va->vm = NULL;
1449                 va->flags &= ~VM_VM_AREA;
1450                 spin_unlock(&vmap_area_lock);
1451 
1452                 vmap_debug_free_range(va->va_start, va->va_end);
1453                 kasan_free_shadow(vm);
1454                 free_unmap_vmap_area(va);
1455 
1456                 return vm;
1457         }
1458         return NULL;
1459 }
1460 
1461 static void __vunmap(const void *addr, int deallocate_pages)
1462 {
1463         struct vm_struct *area;
1464 
1465         if (!addr)
1466                 return;
1467 
1468         if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n",
1469                         addr))
1470                 return;
1471 
1472         area = remove_vm_area(addr);
1473         if (unlikely(!area)) {
1474                 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
1475                                 addr);
1476                 return;
1477         }
1478 
1479         debug_check_no_locks_freed(addr, get_vm_area_size(area));
1480         debug_check_no_obj_freed(addr, get_vm_area_size(area));
1481 
1482         if (deallocate_pages) {
1483                 int i;
1484 
1485                 for (i = 0; i < area->nr_pages; i++) {
1486                         struct page *page = area->pages[i];
1487 
1488                         BUG_ON(!page);
1489                         __free_pages(page, 0);
1490                 }
1491 
1492                 kvfree(area->pages);
1493         }
1494 
1495         kfree(area);
1496         return;
1497 }
1498 
1499 static inline void __vfree_deferred(const void *addr)
1500 {
1501         /*
1502          * Use raw_cpu_ptr() because this can be called from preemptible
1503          * context. Preemption is absolutely fine here, because the llist_add()
1504          * implementation is lockless, so it works even if we are adding to
1505          * nother cpu's list.  schedule_work() should be fine with this too.
1506          */
1507         struct vfree_deferred *p = raw_cpu_ptr(&vfree_deferred);
1508 
1509         if (llist_add((struct llist_node *)addr, &p->list))
1510                 schedule_work(&p->wq);
1511 }
1512 
1513 /**
1514  *      vfree_atomic  -  release memory allocated by vmalloc()
1515  *      @addr:          memory base address
1516  *
1517  *      This one is just like vfree() but can be called in any atomic context
1518  *      except NMIs.
1519  */
1520 void vfree_atomic(const void *addr)
1521 {
1522         BUG_ON(in_nmi());
1523 
1524         kmemleak_free(addr);
1525 
1526         if (!addr)
1527                 return;
1528         __vfree_deferred(addr);
1529 }
1530 
1531 /**
1532  *      vfree  -  release memory allocated by vmalloc()
1533  *      @addr:          memory base address
1534  *
1535  *      Free the virtually continuous memory area starting at @addr, as
1536  *      obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
1537  *      NULL, no operation is performed.
1538  *
1539  *      Must not be called in NMI context (strictly speaking, only if we don't
1540  *      have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
1541  *      conventions for vfree() arch-depenedent would be a really bad idea)
1542  *
1543  *      NOTE: assumes that the object at *addr has a size >= sizeof(llist_node)
1544  */
1545 void vfree(const void *addr)
1546 {
1547         BUG_ON(in_nmi());
1548 
1549         kmemleak_free(addr);
1550 
1551         if (!addr)
1552                 return;
1553         if (unlikely(in_interrupt()))
1554                 __vfree_deferred(addr);
1555         else
1556                 __vunmap(addr, 1);
1557 }
1558 EXPORT_SYMBOL(vfree);
1559 
1560 /**
1561  *      vunmap  -  release virtual mapping obtained by vmap()
1562  *      @addr:          memory base address
1563  *
1564  *      Free the virtually contiguous memory area starting at @addr,
1565  *      which was created from the page array passed to vmap().
1566  *
1567  *      Must not be called in interrupt context.
1568  */
1569 void vunmap(const void *addr)
1570 {
1571         BUG_ON(in_interrupt());
1572         might_sleep();
1573         if (addr)
1574                 __vunmap(addr, 0);
1575 }
1576 EXPORT_SYMBOL(vunmap);
1577 
1578 /**
1579  *      vmap  -  map an array of pages into virtually contiguous space
1580  *      @pages:         array of page pointers
1581  *      @count:         number of pages to map
1582  *      @flags:         vm_area->flags
1583  *      @prot:          page protection for the mapping
1584  *
1585  *      Maps @count pages from @pages into contiguous kernel virtual
1586  *      space.
1587  */
1588 void *vmap(struct page **pages, unsigned int count,
1589                 unsigned long flags, pgprot_t prot)
1590 {
1591         struct vm_struct *area;
1592         unsigned long size;             /* In bytes */
1593 
1594         might_sleep();
1595 
1596         if (count > totalram_pages)
1597                 return NULL;
1598 
1599         size = (unsigned long)count << PAGE_SHIFT;
1600         area = get_vm_area_caller(size, flags, __builtin_return_address(0));
1601         if (!area)
1602                 return NULL;
1603 
1604         if (map_vm_area(area, prot, pages)) {
1605                 vunmap(area->addr);
1606                 return NULL;
1607         }
1608 
1609         return area->addr;
1610 }
1611 EXPORT_SYMBOL(vmap);
1612 
1613 static void *__vmalloc_node(unsigned long size, unsigned long align,
1614                             gfp_t gfp_mask, pgprot_t prot,
1615                             int node, const void *caller);
1616 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
1617                                  pgprot_t prot, int node)
1618 {
1619         struct page **pages;
1620         unsigned int nr_pages, array_size, i;
1621         const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
1622         const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
1623 
1624         nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
1625         array_size = (nr_pages * sizeof(struct page *));
1626 
1627         area->nr_pages = nr_pages;
1628         /* Please note that the recursion is strictly bounded. */
1629         if (array_size > PAGE_SIZE) {
1630                 pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM,
1631                                 PAGE_KERNEL, node, area->caller);
1632         } else {
1633                 pages = kmalloc_node(array_size, nested_gfp, node);
1634         }
1635         area->pages = pages;
1636         if (!area->pages) {
1637                 remove_vm_area(area->addr);
1638                 kfree(area);
1639                 return NULL;
1640         }
1641 
1642         for (i = 0; i < area->nr_pages; i++) {
1643                 struct page *page;
1644 
1645                 if (node == NUMA_NO_NODE)
1646                         page = alloc_page(alloc_mask);
1647                 else
1648                         page = alloc_pages_node(node, alloc_mask, 0);
1649 
1650                 if (unlikely(!page)) {
1651                         /* Successfully allocated i pages, free them in __vunmap() */
1652                         area->nr_pages = i;
1653                         goto fail;
1654                 }
1655                 area->pages[i] = page;
1656                 if (gfpflags_allow_blocking(gfp_mask))
1657                         cond_resched();
1658         }
1659 
1660         if (map_vm_area(area, prot, pages))
1661                 goto fail;
1662         return area->addr;
1663 
1664 fail:
1665         warn_alloc(gfp_mask,
1666                           "vmalloc: allocation failure, allocated %ld of %ld bytes",
1667                           (area->nr_pages*PAGE_SIZE), area->size);
1668         vfree(area->addr);
1669         return NULL;
1670 }
1671 
1672 /**
1673  *      __vmalloc_node_range  -  allocate virtually contiguous memory
1674  *      @size:          allocation size
1675  *      @align:         desired alignment
1676  *      @start:         vm area range start
1677  *      @end:           vm area range end
1678  *      @gfp_mask:      flags for the page level allocator
1679  *      @prot:          protection mask for the allocated pages
1680  *      @vm_flags:      additional vm area flags (e.g. %VM_NO_GUARD)
1681  *      @node:          node to use for allocation or NUMA_NO_NODE
1682  *      @caller:        caller's return address
1683  *
1684  *      Allocate enough pages to cover @size from the page level
1685  *      allocator with @gfp_mask flags.  Map them into contiguous
1686  *      kernel virtual space, using a pagetable protection of @prot.
1687  */
1688 void *__vmalloc_node_range(unsigned long size, unsigned long align,
1689                         unsigned long start, unsigned long end, gfp_t gfp_mask,
1690                         pgprot_t prot, unsigned long vm_flags, int node,
1691                         const void *caller)
1692 {
1693         struct vm_struct *area;
1694         void *addr;
1695         unsigned long real_size = size;
1696 
1697         size = PAGE_ALIGN(size);
1698         if (!size || (size >> PAGE_SHIFT) > totalram_pages)
1699                 goto fail;
1700 
1701         area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED |
1702                                 vm_flags, start, end, node, gfp_mask, caller);
1703         if (!area)
1704                 goto fail;
1705 
1706         addr = __vmalloc_area_node(area, gfp_mask, prot, node);
1707         if (!addr)
1708                 return NULL;
1709 
1710         /*
1711          * In this function, newly allocated vm_struct has VM_UNINITIALIZED
1712          * flag. It means that vm_struct is not fully initialized.
1713          * Now, it is fully initialized, so remove this flag here.
1714          */
1715         clear_vm_uninitialized_flag(area);
1716 
1717         /*
1718          * A ref_count = 2 is needed because vm_struct allocated in
1719          * __get_vm_area_node() contains a reference to the virtual address of
1720          * the vmalloc'ed block.
1721          */
1722         kmemleak_alloc(addr, real_size, 2, gfp_mask);
1723 
1724         return addr;
1725 
1726 fail:
1727         warn_alloc(gfp_mask,
1728                           "vmalloc: allocation failure: %lu bytes", real_size);
1729         return NULL;
1730 }
1731 
1732 /**
1733  *      __vmalloc_node  -  allocate virtually contiguous memory
1734  *      @size:          allocation size
1735  *      @align:         desired alignment
1736  *      @gfp_mask:      flags for the page level allocator
1737  *      @prot:          protection mask for the allocated pages
1738  *      @node:          node to use for allocation or NUMA_NO_NODE
1739  *      @caller:        caller's return address
1740  *
1741  *      Allocate enough pages to cover @size from the page level
1742  *      allocator with @gfp_mask flags.  Map them into contiguous
1743  *      kernel virtual space, using a pagetable protection of @prot.
1744  */
1745 static void *__vmalloc_node(unsigned long size, unsigned long align,
1746                             gfp_t gfp_mask, pgprot_t prot,
1747                             int node, const void *caller)
1748 {
1749         return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
1750                                 gfp_mask, prot, 0, node, caller);
1751 }
1752 
1753 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1754 {
1755         return __vmalloc_node(size, 1, gfp_mask, prot, NUMA_NO_NODE,
1756                                 __builtin_return_address(0));
1757 }
1758 EXPORT_SYMBOL(__vmalloc);
1759 
1760 static inline void *__vmalloc_node_flags(unsigned long size,
1761                                         int node, gfp_t flags)
1762 {
1763         return __vmalloc_node(size, 1, flags, PAGE_KERNEL,
1764                                         node, __builtin_return_address(0));
1765 }
1766 
1767 /**
1768  *      vmalloc  -  allocate virtually contiguous memory
1769  *      @size:          allocation size
1770  *      Allocate enough pages to cover @size from the page level
1771  *      allocator and map them into contiguous kernel virtual space.
1772  *
1773  *      For tight control over page level allocator and protection flags
1774  *      use __vmalloc() instead.
1775  */
1776 void *vmalloc(unsigned long size)
1777 {
1778         return __vmalloc_node_flags(size, NUMA_NO_NODE,
1779                                     GFP_KERNEL | __GFP_HIGHMEM);
1780 }
1781 EXPORT_SYMBOL(vmalloc);
1782 
1783 /**
1784  *      vzalloc - allocate virtually contiguous memory with zero fill
1785  *      @size:  allocation size
1786  *      Allocate enough pages to cover @size from the page level
1787  *      allocator and map them into contiguous kernel virtual space.
1788  *      The memory allocated is set to zero.
1789  *
1790  *      For tight control over page level allocator and protection flags
1791  *      use __vmalloc() instead.
1792  */
1793 void *vzalloc(unsigned long size)
1794 {
1795         return __vmalloc_node_flags(size, NUMA_NO_NODE,
1796                                 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1797 }
1798 EXPORT_SYMBOL(vzalloc);
1799 
1800 /**
1801  * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
1802  * @size: allocation size
1803  *
1804  * The resulting memory area is zeroed so it can be mapped to userspace
1805  * without leaking data.
1806  */
1807 void *vmalloc_user(unsigned long size)
1808 {
1809         struct vm_struct *area;
1810         void *ret;
1811 
1812         ret = __vmalloc_node(size, SHMLBA,
1813                              GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
1814                              PAGE_KERNEL, NUMA_NO_NODE,
1815                              __builtin_return_address(0));
1816         if (ret) {
1817                 area = find_vm_area(ret);
1818                 area->flags |= VM_USERMAP;
1819         }
1820         return ret;
1821 }
1822 EXPORT_SYMBOL(vmalloc_user);
1823 
1824 /**
1825  *      vmalloc_node  -  allocate memory on a specific node
1826  *      @size:          allocation size
1827  *      @node:          numa node
1828  *
1829  *      Allocate enough pages to cover @size from the page level
1830  *      allocator and map them into contiguous kernel virtual space.
1831  *
1832  *      For tight control over page level allocator and protection flags
1833  *      use __vmalloc() instead.
1834  */
1835 void *vmalloc_node(unsigned long size, int node)
1836 {
1837         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
1838                                         node, __builtin_return_address(0));
1839 }
1840 EXPORT_SYMBOL(vmalloc_node);
1841 
1842 /**
1843  * vzalloc_node - allocate memory on a specific node with zero fill
1844  * @size:       allocation size
1845  * @node:       numa node
1846  *
1847  * Allocate enough pages to cover @size from the page level
1848  * allocator and map them into contiguous kernel virtual space.
1849  * The memory allocated is set to zero.
1850  *
1851  * For tight control over page level allocator and protection flags
1852  * use __vmalloc_node() instead.
1853  */
1854 void *vzalloc_node(unsigned long size, int node)
1855 {
1856         return __vmalloc_node_flags(size, node,
1857                          GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1858 }
1859 EXPORT_SYMBOL(vzalloc_node);
1860 
1861 #ifndef PAGE_KERNEL_EXEC
1862 # define PAGE_KERNEL_EXEC PAGE_KERNEL
1863 #endif
1864 
1865 /**
1866  *      vmalloc_exec  -  allocate virtually contiguous, executable memory
1867  *      @size:          allocation size
1868  *
1869  *      Kernel-internal function to allocate enough pages to cover @size
1870  *      the page level allocator and map them into contiguous and
1871  *      executable kernel virtual space.
1872  *
1873  *      For tight control over page level allocator and protection flags
1874  *      use __vmalloc() instead.
1875  */
1876 
1877 void *vmalloc_exec(unsigned long size)
1878 {
1879         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
1880                               NUMA_NO_NODE, __builtin_return_address(0));
1881 }
1882 
1883 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
1884 #define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
1885 #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
1886 #define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
1887 #else
1888 #define GFP_VMALLOC32 GFP_KERNEL
1889 #endif
1890 
1891 /**
1892  *      vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
1893  *      @size:          allocation size
1894  *
1895  *      Allocate enough 32bit PA addressable pages to cover @size from the
1896  *      page level allocator and map them into contiguous kernel virtual space.
1897  */
1898 void *vmalloc_32(unsigned long size)
1899 {
1900         return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
1901                               NUMA_NO_NODE, __builtin_return_address(0));
1902 }
1903 EXPORT_SYMBOL(vmalloc_32);
1904 
1905 /**
1906  * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
1907  *      @size:          allocation size
1908  *
1909  * The resulting memory area is 32bit addressable and zeroed so it can be
1910  * mapped to userspace without leaking data.
1911  */
1912 void *vmalloc_32_user(unsigned long size)
1913 {
1914         struct vm_struct *area;
1915         void *ret;
1916 
1917         ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
1918                              NUMA_NO_NODE, __builtin_return_address(0));
1919         if (ret) {
1920                 area = find_vm_area(ret);
1921                 area->flags |= VM_USERMAP;
1922         }
1923         return ret;
1924 }
1925 EXPORT_SYMBOL(vmalloc_32_user);
1926 
1927 /*
1928  * small helper routine , copy contents to buf from addr.
1929  * If the page is not present, fill zero.
1930  */
1931 
1932 static int aligned_vread(char *buf, char *addr, unsigned long count)
1933 {
1934         struct page *p;
1935         int copied = 0;
1936 
1937         while (count) {
1938                 unsigned long offset, length;
1939 
1940                 offset = offset_in_page(addr);
1941                 length = PAGE_SIZE - offset;
1942                 if (length > count)
1943                         length = count;
1944                 p = vmalloc_to_page(addr);
1945                 /*
1946                  * To do safe access to this _mapped_ area, we need
1947                  * lock. But adding lock here means that we need to add
1948                  * overhead of vmalloc()/vfree() calles for this _debug_
1949                  * interface, rarely used. Instead of that, we'll use
1950                  * kmap() and get small overhead in this access function.
1951                  */
1952                 if (p) {
1953                         /*
1954                          * we can expect USER0 is not used (see vread/vwrite's
1955                          * function description)
1956                          */
1957                         void *map = kmap_atomic(p);
1958                         memcpy(buf, map + offset, length);
1959                         kunmap_atomic(map);
1960                 } else
1961                         memset(buf, 0, length);
1962 
1963                 addr += length;
1964                 buf += length;
1965                 copied += length;
1966                 count -= length;
1967         }
1968         return copied;
1969 }
1970 
1971 static int aligned_vwrite(char *buf, char *addr, unsigned long count)
1972 {
1973         struct page *p;
1974         int copied = 0;
1975 
1976         while (count) {
1977                 unsigned long offset, length;
1978 
1979                 offset = offset_in_page(addr);
1980                 length = PAGE_SIZE - offset;
1981                 if (length > count)
1982                         length = count;
1983                 p = vmalloc_to_page(addr);
1984                 /*
1985                  * To do safe access to this _mapped_ area, we need
1986                  * lock. But adding lock here means that we need to add
1987                  * overhead of vmalloc()/vfree() calles for this _debug_
1988                  * interface, rarely used. Instead of that, we'll use
1989                  * kmap() and get small overhead in this access function.
1990                  */
1991                 if (p) {
1992                         /*
1993                          * we can expect USER0 is not used (see vread/vwrite's
1994                          * function description)
1995                          */
1996                         void *map = kmap_atomic(p);
1997                         memcpy(map + offset, buf, length);
1998                         kunmap_atomic(map);
1999                 }
2000                 addr += length;
2001                 buf += length;
2002                 copied += length;
2003                 count -= length;
2004         }
2005         return copied;
2006 }
2007 
2008 /**
2009  *      vread() -  read vmalloc area in a safe way.
2010  *      @buf:           buffer for reading data
2011  *      @addr:          vm address.
2012  *      @count:         number of bytes to be read.
2013  *
2014  *      Returns # of bytes which addr and buf should be increased.
2015  *      (same number to @count). Returns 0 if [addr...addr+count) doesn't
2016  *      includes any intersect with alive vmalloc area.
2017  *
2018  *      This function checks that addr is a valid vmalloc'ed area, and
2019  *      copy data from that area to a given buffer. If the given memory range
2020  *      of [addr...addr+count) includes some valid address, data is copied to
2021  *      proper area of @buf. If there are memory holes, they'll be zero-filled.
2022  *      IOREMAP area is treated as memory hole and no copy is done.
2023  *
2024  *      If [addr...addr+count) doesn't includes any intersects with alive
2025  *      vm_struct area, returns 0. @buf should be kernel's buffer.
2026  *
2027  *      Note: In usual ops, vread() is never necessary because the caller
2028  *      should know vmalloc() area is valid and can use memcpy().
2029  *      This is for routines which have to access vmalloc area without
2030  *      any informaion, as /dev/kmem.
2031  *
2032  */
2033 
2034 long vread(char *buf, char *addr, unsigned long count)
2035 {
2036         struct vmap_area *va;
2037         struct vm_struct *vm;
2038         char *vaddr, *buf_start = buf;
2039         unsigned long buflen = count;
2040         unsigned long n;
2041 
2042         /* Don't allow overflow */
2043         if ((unsigned long) addr + count < count)
2044                 count = -(unsigned long) addr;
2045 
2046         spin_lock(&vmap_area_lock);
2047         list_for_each_entry(va, &vmap_area_list, list) {
2048                 if (!count)
2049                         break;
2050 
2051                 if (!(va->flags & VM_VM_AREA))
2052                         continue;
2053 
2054                 vm = va->vm;
2055                 vaddr = (char *) vm->addr;
2056                 if (addr >= vaddr + get_vm_area_size(vm))
2057                         continue;
2058                 while (addr < vaddr) {
2059                         if (count == 0)
2060                                 goto finished;
2061                         *buf = '\0';
2062                         buf++;
2063                         addr++;
2064                         count--;
2065                 }
2066                 n = vaddr + get_vm_area_size(vm) - addr;
2067                 if (n > count)
2068                         n = count;
2069                 if (!(vm->flags & VM_IOREMAP))
2070                         aligned_vread(buf, addr, n);
2071                 else /* IOREMAP area is treated as memory hole */
2072                         memset(buf, 0, n);
2073                 buf += n;
2074                 addr += n;
2075                 count -= n;
2076         }
2077 finished:
2078         spin_unlock(&vmap_area_lock);
2079 
2080         if (buf == buf_start)
2081                 return 0;
2082         /* zero-fill memory holes */
2083         if (buf != buf_start + buflen)
2084                 memset(buf, 0, buflen - (buf - buf_start));
2085 
2086         return buflen;
2087 }
2088 
2089 /**
2090  *      vwrite() -  write vmalloc area in a safe way.
2091  *      @buf:           buffer for source data
2092  *      @addr:          vm address.
2093  *      @count:         number of bytes to be read.
2094  *
2095  *      Returns # of bytes which addr and buf should be incresed.
2096  *      (same number to @count).
2097  *      If [addr...addr+count) doesn't includes any intersect with valid
2098  *      vmalloc area, returns 0.
2099  *
2100  *      This function checks that addr is a valid vmalloc'ed area, and
2101  *      copy data from a buffer to the given addr. If specified range of
2102  *      [addr...addr+count) includes some valid address, data is copied from
2103  *      proper area of @buf. If there are memory holes, no copy to hole.
2104  *      IOREMAP area is treated as memory hole and no copy is done.
2105  *
2106  *      If [addr...addr+count) doesn't includes any intersects with alive
2107  *      vm_struct area, returns 0. @buf should be kernel's buffer.
2108  *
2109  *      Note: In usual ops, vwrite() is never necessary because the caller
2110  *      should know vmalloc() area is valid and can use memcpy().
2111  *      This is for routines which have to access vmalloc area without
2112  *      any informaion, as /dev/kmem.
2113  */
2114 
2115 long vwrite(char *buf, char *addr, unsigned long count)
2116 {
2117         struct vmap_area *va;
2118         struct vm_struct *vm;
2119         char *vaddr;
2120         unsigned long n, buflen;
2121         int copied = 0;
2122 
2123         /* Don't allow overflow */
2124         if ((unsigned long) addr + count < count)
2125                 count = -(unsigned long) addr;
2126         buflen = count;
2127 
2128         spin_lock(&vmap_area_lock);
2129         list_for_each_entry(va, &vmap_area_list, list) {
2130                 if (!count)
2131                         break;
2132 
2133                 if (!(va->flags & VM_VM_AREA))
2134                         continue;
2135 
2136                 vm = va->vm;
2137                 vaddr = (char *) vm->addr;
2138                 if (addr >= vaddr + get_vm_area_size(vm))
2139                         continue;
2140                 while (addr < vaddr) {
2141                         if (count == 0)
2142                                 goto finished;
2143                         buf++;
2144                         addr++;
2145                         count--;
2146                 }
2147                 n = vaddr + get_vm_area_size(vm) - addr;
2148                 if (n > count)
2149                         n = count;
2150                 if (!(vm->flags & VM_IOREMAP)) {
2151                         aligned_vwrite(buf, addr, n);
2152                         copied++;
2153                 }
2154                 buf += n;
2155                 addr += n;
2156                 count -= n;
2157         }
2158 finished:
2159         spin_unlock(&vmap_area_lock);
2160         if (!copied)
2161                 return 0;
2162         return buflen;
2163 }
2164 
2165 /**
2166  *      remap_vmalloc_range_partial  -  map vmalloc pages to userspace
2167  *      @vma:           vma to cover
2168  *      @uaddr:         target user address to start at
2169  *      @kaddr:         virtual address of vmalloc kernel memory
2170  *      @size:          size of map area
2171  *
2172  *      Returns:        0 for success, -Exxx on failure
2173  *
2174  *      This function checks that @kaddr is a valid vmalloc'ed area,
2175  *      and that it is big enough to cover the range starting at
2176  *      @uaddr in @vma. Will return failure if that criteria isn't
2177  *      met.
2178  *
2179  *      Similar to remap_pfn_range() (see mm/memory.c)
2180  */
2181 int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
2182                                 void *kaddr, unsigned long size)
2183 {
2184         struct vm_struct *area;
2185 
2186         size = PAGE_ALIGN(size);
2187 
2188         if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr))
2189                 return -EINVAL;
2190 
2191         area = find_vm_area(kaddr);
2192         if (!area)
2193                 return -EINVAL;
2194 
2195         if (!(area->flags & VM_USERMAP))
2196                 return -EINVAL;
2197 
2198         if (kaddr + size > area->addr + area->size)
2199                 return -EINVAL;
2200 
2201         do {
2202                 struct page *page = vmalloc_to_page(kaddr);
2203                 int ret;
2204 
2205                 ret = vm_insert_page(vma, uaddr, page);
2206                 if (ret)
2207                         return ret;
2208 
2209                 uaddr += PAGE_SIZE;
2210                 kaddr += PAGE_SIZE;
2211                 size -= PAGE_SIZE;
2212         } while (size > 0);
2213 
2214         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
2215 
2216         return 0;
2217 }
2218 EXPORT_SYMBOL(remap_vmalloc_range_partial);
2219 
2220 /**
2221  *      remap_vmalloc_range  -  map vmalloc pages to userspace
2222  *      @vma:           vma to cover (map full range of vma)
2223  *      @addr:          vmalloc memory
2224  *      @pgoff:         number of pages into addr before first page to map
2225  *
2226  *      Returns:        0 for success, -Exxx on failure
2227  *
2228  *      This function checks that addr is a valid vmalloc'ed area, and
2229  *      that it is big enough to cover the vma. Will return failure if
2230  *      that criteria isn't met.
2231  *
2232  *      Similar to remap_pfn_range() (see mm/memory.c)
2233  */
2234 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
2235                                                 unsigned long pgoff)
2236 {
2237         return remap_vmalloc_range_partial(vma, vma->vm_start,
2238                                            addr + (pgoff << PAGE_SHIFT),
2239                                            vma->vm_end - vma->vm_start);
2240 }
2241 EXPORT_SYMBOL(remap_vmalloc_range);
2242 
2243 /*
2244  * Implement a stub for vmalloc_sync_all() if the architecture chose not to
2245  * have one.
2246  */
2247 void __weak vmalloc_sync_all(void)
2248 {
2249 }
2250 
2251 
2252 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
2253 {
2254         pte_t ***p = data;
2255 
2256         if (p) {
2257                 *(*p) = pte;
2258                 (*p)++;
2259         }
2260         return 0;
2261 }
2262 
2263 /**
2264  *      alloc_vm_area - allocate a range of kernel address space
2265  *      @size:          size of the area
2266  *      @ptes:          returns the PTEs for the address space
2267  *
2268  *      Returns:        NULL on failure, vm_struct on success
2269  *
2270  *      This function reserves a range of kernel address space, and
2271  *      allocates pagetables to map that range.  No actual mappings
2272  *      are created.
2273  *
2274  *      If @ptes is non-NULL, pointers to the PTEs (in init_mm)
2275  *      allocated for the VM area are returned.
2276  */
2277 struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
2278 {
2279         struct vm_struct *area;
2280 
2281         area = get_vm_area_caller(size, VM_IOREMAP,
2282                                 __builtin_return_address(0));
2283         if (area == NULL)
2284                 return NULL;
2285 
2286         /*
2287          * This ensures that page tables are constructed for this region
2288          * of kernel virtual address space and mapped into init_mm.
2289          */
2290         if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2291                                 size, f, ptes ? &ptes : NULL)) {
2292                 free_vm_area(area);
2293                 return NULL;
2294         }
2295 
2296         return area;
2297 }
2298 EXPORT_SYMBOL_GPL(alloc_vm_area);
2299 
2300 void free_vm_area(struct vm_struct *area)
2301 {
2302         struct vm_struct *ret;
2303         ret = remove_vm_area(area->addr);
2304         BUG_ON(ret != area);
2305         kfree(area);
2306 }
2307 EXPORT_SYMBOL_GPL(free_vm_area);
2308 
2309 #ifdef CONFIG_SMP
2310 static struct vmap_area *node_to_va(struct rb_node *n)
2311 {
2312         return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
2313 }
2314 
2315 /**
2316  * pvm_find_next_prev - find the next and prev vmap_area surrounding @end
2317  * @end: target address
2318  * @pnext: out arg for the next vmap_area
2319  * @pprev: out arg for the previous vmap_area
2320  *
2321  * Returns: %true if either or both of next and prev are found,
2322  *          %false if no vmap_area exists
2323  *
2324  * Find vmap_areas end addresses of which enclose @end.  ie. if not
2325  * NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
2326  */
2327 static bool pvm_find_next_prev(unsigned long end,
2328                                struct vmap_area **pnext,
2329                                struct vmap_area **pprev)
2330 {
2331         struct rb_node *n = vmap_area_root.rb_node;
2332         struct vmap_area *va = NULL;
2333 
2334         while (n) {
2335                 va = rb_entry(n, struct vmap_area, rb_node);
2336                 if (end < va->va_end)
2337                         n = n->rb_left;
2338                 else if (end > va->va_end)
2339                         n = n->rb_right;
2340                 else
2341                         break;
2342         }
2343 
2344         if (!va)
2345                 return false;
2346 
2347         if (va->va_end > end) {
2348                 *pnext = va;
2349                 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2350         } else {
2351                 *pprev = va;
2352                 *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
2353         }
2354         return true;
2355 }
2356 
2357 /**
2358  * pvm_determine_end - find the highest aligned address between two vmap_areas
2359  * @pnext: in/out arg for the next vmap_area
2360  * @pprev: in/out arg for the previous vmap_area
2361  * @align: alignment
2362  *
2363  * Returns: determined end address
2364  *
2365  * Find the highest aligned address between *@pnext and *@pprev below
2366  * VMALLOC_END.  *@pnext and *@pprev are adjusted so that the aligned
2367  * down address is between the end addresses of the two vmap_areas.
2368  *
2369  * Please note that the address returned by this function may fall
2370  * inside *@pnext vmap_area.  The caller is responsible for checking
2371  * that.
2372  */
2373 static unsigned long pvm_determine_end(struct vmap_area **pnext,
2374                                        struct vmap_area **pprev,
2375                                        unsigned long align)
2376 {
2377         const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2378         unsigned long addr;
2379 
2380         if (*pnext)
2381                 addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
2382         else
2383                 addr = vmalloc_end;
2384 
2385         while (*pprev && (*pprev)->va_end > addr) {
2386                 *pnext = *pprev;
2387                 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2388         }
2389 
2390         return addr;
2391 }
2392 
2393 /**
2394  * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
2395  * @offsets: array containing offset of each area
2396  * @sizes: array containing size of each area
2397  * @nr_vms: the number of areas to allocate
2398  * @align: alignment, all entries in @offsets and @sizes must be aligned to this
2399  *
2400  * Returns: kmalloc'd vm_struct pointer array pointing to allocated
2401  *          vm_structs on success, %NULL on failure
2402  *
2403  * Percpu allocator wants to use congruent vm areas so that it can
2404  * maintain the offsets among percpu areas.  This function allocates
2405  * congruent vmalloc areas for it with GFP_KERNEL.  These areas tend to
2406  * be scattered pretty far, distance between two areas easily going up
2407  * to gigabytes.  To avoid interacting with regular vmallocs, these
2408  * areas are allocated from top.
2409  *
2410  * Despite its complicated look, this allocator is rather simple.  It
2411  * does everything top-down and scans areas from the end looking for
2412  * matching slot.  While scanning, if any of the areas overlaps with
2413  * existing vmap_area, the base address is pulled down to fit the
2414  * area.  Scanning is repeated till all the areas fit and then all
2415  * necessary data structres are inserted and the result is returned.
2416  */
2417 struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
2418                                      const size_t *sizes, int nr_vms,
2419                                      size_t align)
2420 {
2421         const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
2422         const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2423         struct vmap_area **vas, *prev, *next;
2424         struct vm_struct **vms;
2425         int area, area2, last_area, term_area;
2426         unsigned long base, start, end, last_end;
2427         bool purged = false;
2428 
2429         /* verify parameters and allocate data structures */
2430         BUG_ON(offset_in_page(align) || !is_power_of_2(align));
2431         for (last_area = 0, area = 0; area < nr_vms; area++) {
2432                 start = offsets[area];
2433                 end = start + sizes[area];
2434 
2435                 /* is everything aligned properly? */
2436                 BUG_ON(!IS_ALIGNED(offsets[area], align));
2437                 BUG_ON(!IS_ALIGNED(sizes[area], align));
2438 
2439                 /* detect the area with the highest address */
2440                 if (start > offsets[last_area])
2441                         last_area = area;
2442 
2443                 for (area2 = 0; area2 < nr_vms; area2++) {
2444                         unsigned long start2 = offsets[area2];
2445                         unsigned long end2 = start2 + sizes[area2];
2446 
2447                         if (area2 == area)
2448                                 continue;
2449 
2450                         BUG_ON(start2 >= start && start2 < end);
2451                         BUG_ON(end2 <= end && end2 > start);
2452                 }
2453         }
2454         last_end = offsets[last_area] + sizes[last_area];
2455 
2456         if (vmalloc_end - vmalloc_start < last_end) {
2457                 WARN_ON(true);
2458                 return NULL;
2459         }
2460 
2461         vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
2462         vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
2463         if (!vas || !vms)
2464                 goto err_free2;
2465 
2466         for (area = 0; area < nr_vms; area++) {
2467                 vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL);
2468                 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
2469                 if (!vas[area] || !vms[area])
2470                         goto err_free;
2471         }
2472 retry:
2473         spin_lock(&vmap_area_lock);
2474 
2475         /* start scanning - we scan from the top, begin with the last area */
2476         area = term_area = last_area;
2477         start = offsets[area];
2478         end = start + sizes[area];
2479 
2480         if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
2481                 base = vmalloc_end - last_end;
2482                 goto found;
2483         }
2484         base = pvm_determine_end(&next, &prev, align) - end;
2485 
2486         while (true) {
2487                 BUG_ON(next && next->va_end <= base + end);
2488                 BUG_ON(prev && prev->va_end > base + end);
2489 
2490                 /*
2491                  * base might have underflowed, add last_end before
2492                  * comparing.
2493                  */
2494                 if (base + last_end < vmalloc_start + last_end) {
2495                         spin_unlock(&vmap_area_lock);
2496                         if (!purged) {
2497                                 purge_vmap_area_lazy();
2498                                 purged = true;
2499                                 goto retry;
2500                         }
2501                         goto err_free;
2502                 }
2503 
2504                 /*
2505                  * If next overlaps, move base downwards so that it's
2506                  * right below next and then recheck.
2507                  */
2508                 if (next && next->va_start < base + end) {
2509                         base = pvm_determine_end(&next, &prev, align) - end;
2510                         term_area = area;
2511                         continue;
2512                 }
2513 
2514                 /*
2515                  * If prev overlaps, shift down next and prev and move
2516                  * base so that it's right below new next and then
2517                  * recheck.
2518                  */
2519                 if (prev && prev->va_end > base + start)  {
2520                         next = prev;
2521                         prev = node_to_va(rb_prev(&next->rb_node));
2522                         base = pvm_determine_end(&next, &prev, align) - end;
2523                         term_area = area;
2524                         continue;
2525                 }
2526 
2527                 /*
2528                  * This area fits, move on to the previous one.  If
2529                  * the previous one is the terminal one, we're done.
2530                  */
2531                 area = (area + nr_vms - 1) % nr_vms;
2532                 if (area == term_area)
2533                         break;
2534                 start = offsets[area];
2535                 end = start + sizes[area];
2536                 pvm_find_next_prev(base + end, &next, &prev);
2537         }
2538 found:
2539         /* we've found a fitting base, insert all va's */
2540         for (area = 0; area < nr_vms; area++) {
2541                 struct vmap_area *va = vas[area];
2542 
2543                 va->va_start = base + offsets[area];
2544                 va->va_end = va->va_start + sizes[area];
2545                 __insert_vmap_area(va);
2546         }
2547 
2548         vmap_area_pcpu_hole = base + offsets[last_area];
2549 
2550         spin_unlock(&vmap_area_lock);
2551 
2552         /* insert all vm's */
2553         for (area = 0; area < nr_vms; area++)
2554                 setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
2555                                  pcpu_get_vm_areas);
2556 
2557         kfree(vas);
2558         return vms;
2559 
2560 err_free:
2561         for (area = 0; area < nr_vms; area++) {
2562                 kfree(vas[area]);
2563                 kfree(vms[area]);
2564         }
2565 err_free2:
2566         kfree(vas);
2567         kfree(vms);
2568         return NULL;
2569 }
2570 
2571 /**
2572  * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
2573  * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
2574  * @nr_vms: the number of allocated areas
2575  *
2576  * Free vm_structs and the array allocated by pcpu_get_vm_areas().
2577  */
2578 void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
2579 {
2580         int i;
2581 
2582         for (i = 0; i < nr_vms; i++)
2583                 free_vm_area(vms[i]);
2584         kfree(vms);
2585 }
2586 #endif  /* CONFIG_SMP */
2587 
2588 #ifdef CONFIG_PROC_FS
2589 static void *s_start(struct seq_file *m, loff_t *pos)
2590         __acquires(&vmap_area_lock)
2591 {
2592         spin_lock(&vmap_area_lock);
2593         return seq_list_start(&vmap_area_list, *pos);
2594 }
2595 
2596 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2597 {
2598         return seq_list_next(p, &vmap_area_list, pos);
2599 }
2600 
2601 static void s_stop(struct seq_file *m, void *p)
2602         __releases(&vmap_area_lock)
2603 {
2604         spin_unlock(&vmap_area_lock);
2605 }
2606 
2607 static void show_numa_info(struct seq_file *m, struct vm_struct *v)
2608 {
2609         if (IS_ENABLED(CONFIG_NUMA)) {
2610                 unsigned int nr, *counters = m->private;
2611 
2612                 if (!counters)
2613                         return;
2614 
2615                 if (v->flags & VM_UNINITIALIZED)
2616                         return;
2617                 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
2618                 smp_rmb();
2619 
2620                 memset(counters, 0, nr_node_ids * sizeof(unsigned int));
2621 
2622                 for (nr = 0; nr < v->nr_pages; nr++)
2623                         counters[page_to_nid(v->pages[nr])]++;
2624 
2625                 for_each_node_state(nr, N_HIGH_MEMORY)
2626                         if (counters[nr])
2627                                 seq_printf(m, " N%u=%u", nr, counters[nr]);
2628         }
2629 }
2630 
2631 static int s_show(struct seq_file *m, void *p)
2632 {
2633         struct vmap_area *va;
2634         struct vm_struct *v;
2635 
2636         va = list_entry(p, struct vmap_area, list);
2637 
2638         /*
2639          * s_show can encounter race with remove_vm_area, !VM_VM_AREA on
2640          * behalf of vmap area is being tear down or vm_map_ram allocation.
2641          */
2642         if (!(va->flags & VM_VM_AREA))
2643                 return 0;
2644 
2645         v = va->vm;
2646 
2647         seq_printf(m, "0x%pK-0x%pK %7ld",
2648                 v->addr, v->addr + v->size, v->size);
2649 
2650         if (v->caller)
2651                 seq_printf(m, " %pS", v->caller);
2652 
2653         if (v->nr_pages)
2654                 seq_printf(m, " pages=%d", v->nr_pages);
2655 
2656         if (v->phys_addr)
2657                 seq_printf(m, " phys=%llx", (unsigned long long)v->phys_addr);
2658 
2659         if (v->flags & VM_IOREMAP)
2660                 seq_puts(m, " ioremap");
2661 
2662         if (v->flags & VM_ALLOC)
2663                 seq_puts(m, " vmalloc");
2664 
2665         if (v->flags & VM_MAP)
2666                 seq_puts(m, " vmap");
2667 
2668         if (v->flags & VM_USERMAP)
2669                 seq_puts(m, " user");
2670 
2671         if (is_vmalloc_addr(v->pages))
2672                 seq_puts(m, " vpages");
2673 
2674         show_numa_info(m, v);
2675         seq_putc(m, '\n');
2676         return 0;
2677 }
2678 
2679 static const struct seq_operations vmalloc_op = {
2680         .start = s_start,
2681         .next = s_next,
2682         .stop = s_stop,
2683         .show = s_show,
2684 };
2685 
2686 static int vmalloc_open(struct inode *inode, struct file *file)
2687 {
2688         if (IS_ENABLED(CONFIG_NUMA))
2689                 return seq_open_private(file, &vmalloc_op,
2690                                         nr_node_ids * sizeof(unsigned int));
2691         else
2692                 return seq_open(file, &vmalloc_op);
2693 }
2694 
2695 static const struct file_operations proc_vmalloc_operations = {
2696         .open           = vmalloc_open,
2697         .read           = seq_read,
2698         .llseek         = seq_lseek,
2699         .release        = seq_release_private,
2700 };
2701 
2702 static int __init proc_vmalloc_init(void)
2703 {
2704         proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
2705         return 0;
2706 }
2707 module_init(proc_vmalloc_init);
2708 
2709 #endif
2710 
2711 

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