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Linux/include/linux/mm.h

  1 #ifndef _LINUX_MM_H
  2 #define _LINUX_MM_H
  3 
  4 #include <linux/errno.h>
  5 
  6 #ifdef __KERNEL__
  7 
  8 #include <linux/mmdebug.h>
  9 #include <linux/gfp.h>
 10 #include <linux/bug.h>
 11 #include <linux/list.h>
 12 #include <linux/mmzone.h>
 13 #include <linux/rbtree.h>
 14 #include <linux/atomic.h>
 15 #include <linux/debug_locks.h>
 16 #include <linux/mm_types.h>
 17 #include <linux/range.h>
 18 #include <linux/pfn.h>
 19 #include <linux/bit_spinlock.h>
 20 #include <linux/shrinker.h>
 21 #include <linux/resource.h>
 22 #include <linux/page_ext.h>
 23 
 24 struct mempolicy;
 25 struct anon_vma;
 26 struct anon_vma_chain;
 27 struct file_ra_state;
 28 struct user_struct;
 29 struct writeback_control;
 30 
 31 #ifndef CONFIG_NEED_MULTIPLE_NODES      /* Don't use mapnrs, do it properly */
 32 extern unsigned long max_mapnr;
 33 
 34 static inline void set_max_mapnr(unsigned long limit)
 35 {
 36         max_mapnr = limit;
 37 }
 38 #else
 39 static inline void set_max_mapnr(unsigned long limit) { }
 40 #endif
 41 
 42 extern unsigned long totalram_pages;
 43 extern void * high_memory;
 44 extern int page_cluster;
 45 
 46 #ifdef CONFIG_SYSCTL
 47 extern int sysctl_legacy_va_layout;
 48 #else
 49 #define sysctl_legacy_va_layout 0
 50 #endif
 51 
 52 #include <asm/page.h>
 53 #include <asm/pgtable.h>
 54 #include <asm/processor.h>
 55 
 56 #ifndef __pa_symbol
 57 #define __pa_symbol(x)  __pa(RELOC_HIDE((unsigned long)(x), 0))
 58 #endif
 59 
 60 /*
 61  * To prevent common memory management code establishing
 62  * a zero page mapping on a read fault.
 63  * This macro should be defined within <asm/pgtable.h>.
 64  * s390 does this to prevent multiplexing of hardware bits
 65  * related to the physical page in case of virtualization.
 66  */
 67 #ifndef mm_forbids_zeropage
 68 #define mm_forbids_zeropage(X)  (0)
 69 #endif
 70 
 71 extern unsigned long sysctl_user_reserve_kbytes;
 72 extern unsigned long sysctl_admin_reserve_kbytes;
 73 
 74 extern int sysctl_overcommit_memory;
 75 extern int sysctl_overcommit_ratio;
 76 extern unsigned long sysctl_overcommit_kbytes;
 77 
 78 extern int overcommit_ratio_handler(struct ctl_table *, int, void __user *,
 79                                     size_t *, loff_t *);
 80 extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
 81                                     size_t *, loff_t *);
 82 
 83 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
 84 
 85 /* to align the pointer to the (next) page boundary */
 86 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
 87 
 88 /* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
 89 #define PAGE_ALIGNED(addr)      IS_ALIGNED((unsigned long)addr, PAGE_SIZE)
 90 
 91 /*
 92  * Linux kernel virtual memory manager primitives.
 93  * The idea being to have a "virtual" mm in the same way
 94  * we have a virtual fs - giving a cleaner interface to the
 95  * mm details, and allowing different kinds of memory mappings
 96  * (from shared memory to executable loading to arbitrary
 97  * mmap() functions).
 98  */
 99 
100 extern struct kmem_cache *vm_area_cachep;
101 
102 #ifndef CONFIG_MMU
103 extern struct rb_root nommu_region_tree;
104 extern struct rw_semaphore nommu_region_sem;
105 
106 extern unsigned int kobjsize(const void *objp);
107 #endif
108 
109 /*
110  * vm_flags in vm_area_struct, see mm_types.h.
111  */
112 #define VM_NONE         0x00000000
113 
114 #define VM_READ         0x00000001      /* currently active flags */
115 #define VM_WRITE        0x00000002
116 #define VM_EXEC         0x00000004
117 #define VM_SHARED       0x00000008
118 
119 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
120 #define VM_MAYREAD      0x00000010      /* limits for mprotect() etc */
121 #define VM_MAYWRITE     0x00000020
122 #define VM_MAYEXEC      0x00000040
123 #define VM_MAYSHARE     0x00000080
124 
125 #define VM_GROWSDOWN    0x00000100      /* general info on the segment */
126 #define VM_PFNMAP       0x00000400      /* Page-ranges managed without "struct page", just pure PFN */
127 #define VM_DENYWRITE    0x00000800      /* ETXTBSY on write attempts.. */
128 
129 #define VM_LOCKED       0x00002000
130 #define VM_IO           0x00004000      /* Memory mapped I/O or similar */
131 
132                                         /* Used by sys_madvise() */
133 #define VM_SEQ_READ     0x00008000      /* App will access data sequentially */
134 #define VM_RAND_READ    0x00010000      /* App will not benefit from clustered reads */
135 
136 #define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
137 #define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
138 #define VM_ACCOUNT      0x00100000      /* Is a VM accounted object */
139 #define VM_NORESERVE    0x00200000      /* should the VM suppress accounting */
140 #define VM_HUGETLB      0x00400000      /* Huge TLB Page VM */
141 #define VM_ARCH_1       0x01000000      /* Architecture-specific flag */
142 #define VM_ARCH_2       0x02000000
143 #define VM_DONTDUMP     0x04000000      /* Do not include in the core dump */
144 
145 #ifdef CONFIG_MEM_SOFT_DIRTY
146 # define VM_SOFTDIRTY   0x08000000      /* Not soft dirty clean area */
147 #else
148 # define VM_SOFTDIRTY   0
149 #endif
150 
151 #define VM_MIXEDMAP     0x10000000      /* Can contain "struct page" and pure PFN pages */
152 #define VM_HUGEPAGE     0x20000000      /* MADV_HUGEPAGE marked this vma */
153 #define VM_NOHUGEPAGE   0x40000000      /* MADV_NOHUGEPAGE marked this vma */
154 #define VM_MERGEABLE    0x80000000      /* KSM may merge identical pages */
155 
156 #if defined(CONFIG_X86)
157 # define VM_PAT         VM_ARCH_1       /* PAT reserves whole VMA at once (x86) */
158 #elif defined(CONFIG_PPC)
159 # define VM_SAO         VM_ARCH_1       /* Strong Access Ordering (powerpc) */
160 #elif defined(CONFIG_PARISC)
161 # define VM_GROWSUP     VM_ARCH_1
162 #elif defined(CONFIG_METAG)
163 # define VM_GROWSUP     VM_ARCH_1
164 #elif defined(CONFIG_IA64)
165 # define VM_GROWSUP     VM_ARCH_1
166 #elif !defined(CONFIG_MMU)
167 # define VM_MAPPED_COPY VM_ARCH_1       /* T if mapped copy of data (nommu mmap) */
168 #endif
169 
170 #if defined(CONFIG_X86)
171 /* MPX specific bounds table or bounds directory */
172 # define VM_MPX         VM_ARCH_2
173 #endif
174 
175 #ifndef VM_GROWSUP
176 # define VM_GROWSUP     VM_NONE
177 #endif
178 
179 /* Bits set in the VMA until the stack is in its final location */
180 #define VM_STACK_INCOMPLETE_SETUP       (VM_RAND_READ | VM_SEQ_READ)
181 
182 #ifndef VM_STACK_DEFAULT_FLAGS          /* arch can override this */
183 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
184 #endif
185 
186 #ifdef CONFIG_STACK_GROWSUP
187 #define VM_STACK_FLAGS  (VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
188 #else
189 #define VM_STACK_FLAGS  (VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
190 #endif
191 
192 /*
193  * Special vmas that are non-mergable, non-mlock()able.
194  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
195  */
196 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
197 
198 /* This mask defines which mm->def_flags a process can inherit its parent */
199 #define VM_INIT_DEF_MASK        VM_NOHUGEPAGE
200 
201 /*
202  * mapping from the currently active vm_flags protection bits (the
203  * low four bits) to a page protection mask..
204  */
205 extern pgprot_t protection_map[16];
206 
207 #define FAULT_FLAG_WRITE        0x01    /* Fault was a write access */
208 #define FAULT_FLAG_MKWRITE      0x02    /* Fault was mkwrite of existing pte */
209 #define FAULT_FLAG_ALLOW_RETRY  0x04    /* Retry fault if blocking */
210 #define FAULT_FLAG_RETRY_NOWAIT 0x08    /* Don't drop mmap_sem and wait when retrying */
211 #define FAULT_FLAG_KILLABLE     0x10    /* The fault task is in SIGKILL killable region */
212 #define FAULT_FLAG_TRIED        0x20    /* Second try */
213 #define FAULT_FLAG_USER         0x40    /* The fault originated in userspace */
214 
215 /*
216  * vm_fault is filled by the the pagefault handler and passed to the vma's
217  * ->fault function. The vma's ->fault is responsible for returning a bitmask
218  * of VM_FAULT_xxx flags that give details about how the fault was handled.
219  *
220  * pgoff should be used in favour of virtual_address, if possible.
221  */
222 struct vm_fault {
223         unsigned int flags;             /* FAULT_FLAG_xxx flags */
224         pgoff_t pgoff;                  /* Logical page offset based on vma */
225         void __user *virtual_address;   /* Faulting virtual address */
226 
227         struct page *cow_page;          /* Handler may choose to COW */
228         struct page *page;              /* ->fault handlers should return a
229                                          * page here, unless VM_FAULT_NOPAGE
230                                          * is set (which is also implied by
231                                          * VM_FAULT_ERROR).
232                                          */
233         /* for ->map_pages() only */
234         pgoff_t max_pgoff;              /* map pages for offset from pgoff till
235                                          * max_pgoff inclusive */
236         pte_t *pte;                     /* pte entry associated with ->pgoff */
237 };
238 
239 /*
240  * These are the virtual MM functions - opening of an area, closing and
241  * unmapping it (needed to keep files on disk up-to-date etc), pointer
242  * to the functions called when a no-page or a wp-page exception occurs. 
243  */
244 struct vm_operations_struct {
245         void (*open)(struct vm_area_struct * area);
246         void (*close)(struct vm_area_struct * area);
247         int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
248         void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);
249 
250         /* notification that a previously read-only page is about to become
251          * writable, if an error is returned it will cause a SIGBUS */
252         int (*page_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
253 
254         /* same as page_mkwrite when using VM_PFNMAP|VM_MIXEDMAP */
255         int (*pfn_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
256 
257         /* called by access_process_vm when get_user_pages() fails, typically
258          * for use by special VMAs that can switch between memory and hardware
259          */
260         int (*access)(struct vm_area_struct *vma, unsigned long addr,
261                       void *buf, int len, int write);
262 
263         /* Called by the /proc/PID/maps code to ask the vma whether it
264          * has a special name.  Returning non-NULL will also cause this
265          * vma to be dumped unconditionally. */
266         const char *(*name)(struct vm_area_struct *vma);
267 
268 #ifdef CONFIG_NUMA
269         /*
270          * set_policy() op must add a reference to any non-NULL @new mempolicy
271          * to hold the policy upon return.  Caller should pass NULL @new to
272          * remove a policy and fall back to surrounding context--i.e. do not
273          * install a MPOL_DEFAULT policy, nor the task or system default
274          * mempolicy.
275          */
276         int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
277 
278         /*
279          * get_policy() op must add reference [mpol_get()] to any policy at
280          * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
281          * in mm/mempolicy.c will do this automatically.
282          * get_policy() must NOT add a ref if the policy at (vma,addr) is not
283          * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
284          * If no [shared/vma] mempolicy exists at the addr, get_policy() op
285          * must return NULL--i.e., do not "fallback" to task or system default
286          * policy.
287          */
288         struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
289                                         unsigned long addr);
290 #endif
291         /*
292          * Called by vm_normal_page() for special PTEs to find the
293          * page for @addr.  This is useful if the default behavior
294          * (using pte_page()) would not find the correct page.
295          */
296         struct page *(*find_special_page)(struct vm_area_struct *vma,
297                                           unsigned long addr);
298 };
299 
300 struct mmu_gather;
301 struct inode;
302 
303 #define page_private(page)              ((page)->private)
304 #define set_page_private(page, v)       ((page)->private = (v))
305 
306 /* It's valid only if the page is free path or free_list */
307 static inline void set_freepage_migratetype(struct page *page, int migratetype)
308 {
309         page->index = migratetype;
310 }
311 
312 /* It's valid only if the page is free path or free_list */
313 static inline int get_freepage_migratetype(struct page *page)
314 {
315         return page->index;
316 }
317 
318 /*
319  * FIXME: take this include out, include page-flags.h in
320  * files which need it (119 of them)
321  */
322 #include <linux/page-flags.h>
323 #include <linux/huge_mm.h>
324 
325 /*
326  * Methods to modify the page usage count.
327  *
328  * What counts for a page usage:
329  * - cache mapping   (page->mapping)
330  * - private data    (page->private)
331  * - page mapped in a task's page tables, each mapping
332  *   is counted separately
333  *
334  * Also, many kernel routines increase the page count before a critical
335  * routine so they can be sure the page doesn't go away from under them.
336  */
337 
338 /*
339  * Drop a ref, return true if the refcount fell to zero (the page has no users)
340  */
341 static inline int put_page_testzero(struct page *page)
342 {
343         VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0, page);
344         return atomic_dec_and_test(&page->_count);
345 }
346 
347 /*
348  * Try to grab a ref unless the page has a refcount of zero, return false if
349  * that is the case.
350  * This can be called when MMU is off so it must not access
351  * any of the virtual mappings.
352  */
353 static inline int get_page_unless_zero(struct page *page)
354 {
355         return atomic_inc_not_zero(&page->_count);
356 }
357 
358 /*
359  * Try to drop a ref unless the page has a refcount of one, return false if
360  * that is the case.
361  * This is to make sure that the refcount won't become zero after this drop.
362  * This can be called when MMU is off so it must not access
363  * any of the virtual mappings.
364  */
365 static inline int put_page_unless_one(struct page *page)
366 {
367         return atomic_add_unless(&page->_count, -1, 1);
368 }
369 
370 extern int page_is_ram(unsigned long pfn);
371 extern int region_is_ram(resource_size_t phys_addr, unsigned long size);
372 
373 /* Support for virtually mapped pages */
374 struct page *vmalloc_to_page(const void *addr);
375 unsigned long vmalloc_to_pfn(const void *addr);
376 
377 /*
378  * Determine if an address is within the vmalloc range
379  *
380  * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
381  * is no special casing required.
382  */
383 static inline int is_vmalloc_addr(const void *x)
384 {
385 #ifdef CONFIG_MMU
386         unsigned long addr = (unsigned long)x;
387 
388         return addr >= VMALLOC_START && addr < VMALLOC_END;
389 #else
390         return 0;
391 #endif
392 }
393 #ifdef CONFIG_MMU
394 extern int is_vmalloc_or_module_addr(const void *x);
395 #else
396 static inline int is_vmalloc_or_module_addr(const void *x)
397 {
398         return 0;
399 }
400 #endif
401 
402 extern void kvfree(const void *addr);
403 
404 static inline void compound_lock(struct page *page)
405 {
406 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
407         VM_BUG_ON_PAGE(PageSlab(page), page);
408         bit_spin_lock(PG_compound_lock, &page->flags);
409 #endif
410 }
411 
412 static inline void compound_unlock(struct page *page)
413 {
414 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
415         VM_BUG_ON_PAGE(PageSlab(page), page);
416         bit_spin_unlock(PG_compound_lock, &page->flags);
417 #endif
418 }
419 
420 static inline unsigned long compound_lock_irqsave(struct page *page)
421 {
422         unsigned long uninitialized_var(flags);
423 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
424         local_irq_save(flags);
425         compound_lock(page);
426 #endif
427         return flags;
428 }
429 
430 static inline void compound_unlock_irqrestore(struct page *page,
431                                               unsigned long flags)
432 {
433 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
434         compound_unlock(page);
435         local_irq_restore(flags);
436 #endif
437 }
438 
439 static inline struct page *compound_head_by_tail(struct page *tail)
440 {
441         struct page *head = tail->first_page;
442 
443         /*
444          * page->first_page may be a dangling pointer to an old
445          * compound page, so recheck that it is still a tail
446          * page before returning.
447          */
448         smp_rmb();
449         if (likely(PageTail(tail)))
450                 return head;
451         return tail;
452 }
453 
454 /*
455  * Since either compound page could be dismantled asynchronously in THP
456  * or we access asynchronously arbitrary positioned struct page, there
457  * would be tail flag race. To handle this race, we should call
458  * smp_rmb() before checking tail flag. compound_head_by_tail() did it.
459  */
460 static inline struct page *compound_head(struct page *page)
461 {
462         if (unlikely(PageTail(page)))
463                 return compound_head_by_tail(page);
464         return page;
465 }
466 
467 /*
468  * If we access compound page synchronously such as access to
469  * allocated page, there is no need to handle tail flag race, so we can
470  * check tail flag directly without any synchronization primitive.
471  */
472 static inline struct page *compound_head_fast(struct page *page)
473 {
474         if (unlikely(PageTail(page)))
475                 return page->first_page;
476         return page;
477 }
478 
479 /*
480  * The atomic page->_mapcount, starts from -1: so that transitions
481  * both from it and to it can be tracked, using atomic_inc_and_test
482  * and atomic_add_negative(-1).
483  */
484 static inline void page_mapcount_reset(struct page *page)
485 {
486         atomic_set(&(page)->_mapcount, -1);
487 }
488 
489 static inline int page_mapcount(struct page *page)
490 {
491         VM_BUG_ON_PAGE(PageSlab(page), page);
492         return atomic_read(&page->_mapcount) + 1;
493 }
494 
495 static inline int page_count(struct page *page)
496 {
497         return atomic_read(&compound_head(page)->_count);
498 }
499 
500 static inline bool __compound_tail_refcounted(struct page *page)
501 {
502         return !PageSlab(page) && !PageHeadHuge(page);
503 }
504 
505 /*
506  * This takes a head page as parameter and tells if the
507  * tail page reference counting can be skipped.
508  *
509  * For this to be safe, PageSlab and PageHeadHuge must remain true on
510  * any given page where they return true here, until all tail pins
511  * have been released.
512  */
513 static inline bool compound_tail_refcounted(struct page *page)
514 {
515         VM_BUG_ON_PAGE(!PageHead(page), page);
516         return __compound_tail_refcounted(page);
517 }
518 
519 static inline void get_huge_page_tail(struct page *page)
520 {
521         /*
522          * __split_huge_page_refcount() cannot run from under us.
523          */
524         VM_BUG_ON_PAGE(!PageTail(page), page);
525         VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
526         VM_BUG_ON_PAGE(atomic_read(&page->_count) != 0, page);
527         if (compound_tail_refcounted(page->first_page))
528                 atomic_inc(&page->_mapcount);
529 }
530 
531 extern bool __get_page_tail(struct page *page);
532 
533 static inline void get_page(struct page *page)
534 {
535         if (unlikely(PageTail(page)))
536                 if (likely(__get_page_tail(page)))
537                         return;
538         /*
539          * Getting a normal page or the head of a compound page
540          * requires to already have an elevated page->_count.
541          */
542         VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);
543         atomic_inc(&page->_count);
544 }
545 
546 static inline struct page *virt_to_head_page(const void *x)
547 {
548         struct page *page = virt_to_page(x);
549 
550         /*
551          * We don't need to worry about synchronization of tail flag
552          * when we call virt_to_head_page() since it is only called for
553          * already allocated page and this page won't be freed until
554          * this virt_to_head_page() is finished. So use _fast variant.
555          */
556         return compound_head_fast(page);
557 }
558 
559 /*
560  * Setup the page count before being freed into the page allocator for
561  * the first time (boot or memory hotplug)
562  */
563 static inline void init_page_count(struct page *page)
564 {
565         atomic_set(&page->_count, 1);
566 }
567 
568 void put_page(struct page *page);
569 void put_pages_list(struct list_head *pages);
570 
571 void split_page(struct page *page, unsigned int order);
572 int split_free_page(struct page *page);
573 
574 /*
575  * Compound pages have a destructor function.  Provide a
576  * prototype for that function and accessor functions.
577  * These are _only_ valid on the head of a PG_compound page.
578  */
579 
580 static inline void set_compound_page_dtor(struct page *page,
581                                                 compound_page_dtor *dtor)
582 {
583         page[1].compound_dtor = dtor;
584 }
585 
586 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
587 {
588         return page[1].compound_dtor;
589 }
590 
591 static inline int compound_order(struct page *page)
592 {
593         if (!PageHead(page))
594                 return 0;
595         return page[1].compound_order;
596 }
597 
598 static inline void set_compound_order(struct page *page, unsigned long order)
599 {
600         page[1].compound_order = order;
601 }
602 
603 #ifdef CONFIG_MMU
604 /*
605  * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
606  * servicing faults for write access.  In the normal case, do always want
607  * pte_mkwrite.  But get_user_pages can cause write faults for mappings
608  * that do not have writing enabled, when used by access_process_vm.
609  */
610 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
611 {
612         if (likely(vma->vm_flags & VM_WRITE))
613                 pte = pte_mkwrite(pte);
614         return pte;
615 }
616 
617 void do_set_pte(struct vm_area_struct *vma, unsigned long address,
618                 struct page *page, pte_t *pte, bool write, bool anon);
619 #endif
620 
621 /*
622  * Multiple processes may "see" the same page. E.g. for untouched
623  * mappings of /dev/null, all processes see the same page full of
624  * zeroes, and text pages of executables and shared libraries have
625  * only one copy in memory, at most, normally.
626  *
627  * For the non-reserved pages, page_count(page) denotes a reference count.
628  *   page_count() == 0 means the page is free. page->lru is then used for
629  *   freelist management in the buddy allocator.
630  *   page_count() > 0  means the page has been allocated.
631  *
632  * Pages are allocated by the slab allocator in order to provide memory
633  * to kmalloc and kmem_cache_alloc. In this case, the management of the
634  * page, and the fields in 'struct page' are the responsibility of mm/slab.c
635  * unless a particular usage is carefully commented. (the responsibility of
636  * freeing the kmalloc memory is the caller's, of course).
637  *
638  * A page may be used by anyone else who does a __get_free_page().
639  * In this case, page_count still tracks the references, and should only
640  * be used through the normal accessor functions. The top bits of page->flags
641  * and page->virtual store page management information, but all other fields
642  * are unused and could be used privately, carefully. The management of this
643  * page is the responsibility of the one who allocated it, and those who have
644  * subsequently been given references to it.
645  *
646  * The other pages (we may call them "pagecache pages") are completely
647  * managed by the Linux memory manager: I/O, buffers, swapping etc.
648  * The following discussion applies only to them.
649  *
650  * A pagecache page contains an opaque `private' member, which belongs to the
651  * page's address_space. Usually, this is the address of a circular list of
652  * the page's disk buffers. PG_private must be set to tell the VM to call
653  * into the filesystem to release these pages.
654  *
655  * A page may belong to an inode's memory mapping. In this case, page->mapping
656  * is the pointer to the inode, and page->index is the file offset of the page,
657  * in units of PAGE_CACHE_SIZE.
658  *
659  * If pagecache pages are not associated with an inode, they are said to be
660  * anonymous pages. These may become associated with the swapcache, and in that
661  * case PG_swapcache is set, and page->private is an offset into the swapcache.
662  *
663  * In either case (swapcache or inode backed), the pagecache itself holds one
664  * reference to the page. Setting PG_private should also increment the
665  * refcount. The each user mapping also has a reference to the page.
666  *
667  * The pagecache pages are stored in a per-mapping radix tree, which is
668  * rooted at mapping->page_tree, and indexed by offset.
669  * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
670  * lists, we instead now tag pages as dirty/writeback in the radix tree.
671  *
672  * All pagecache pages may be subject to I/O:
673  * - inode pages may need to be read from disk,
674  * - inode pages which have been modified and are MAP_SHARED may need
675  *   to be written back to the inode on disk,
676  * - anonymous pages (including MAP_PRIVATE file mappings) which have been
677  *   modified may need to be swapped out to swap space and (later) to be read
678  *   back into memory.
679  */
680 
681 /*
682  * The zone field is never updated after free_area_init_core()
683  * sets it, so none of the operations on it need to be atomic.
684  */
685 
686 /* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
687 #define SECTIONS_PGOFF          ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
688 #define NODES_PGOFF             (SECTIONS_PGOFF - NODES_WIDTH)
689 #define ZONES_PGOFF             (NODES_PGOFF - ZONES_WIDTH)
690 #define LAST_CPUPID_PGOFF       (ZONES_PGOFF - LAST_CPUPID_WIDTH)
691 
692 /*
693  * Define the bit shifts to access each section.  For non-existent
694  * sections we define the shift as 0; that plus a 0 mask ensures
695  * the compiler will optimise away reference to them.
696  */
697 #define SECTIONS_PGSHIFT        (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
698 #define NODES_PGSHIFT           (NODES_PGOFF * (NODES_WIDTH != 0))
699 #define ZONES_PGSHIFT           (ZONES_PGOFF * (ZONES_WIDTH != 0))
700 #define LAST_CPUPID_PGSHIFT     (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
701 
702 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
703 #ifdef NODE_NOT_IN_PAGE_FLAGS
704 #define ZONEID_SHIFT            (SECTIONS_SHIFT + ZONES_SHIFT)
705 #define ZONEID_PGOFF            ((SECTIONS_PGOFF < ZONES_PGOFF)? \
706                                                 SECTIONS_PGOFF : ZONES_PGOFF)
707 #else
708 #define ZONEID_SHIFT            (NODES_SHIFT + ZONES_SHIFT)
709 #define ZONEID_PGOFF            ((NODES_PGOFF < ZONES_PGOFF)? \
710                                                 NODES_PGOFF : ZONES_PGOFF)
711 #endif
712 
713 #define ZONEID_PGSHIFT          (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
714 
715 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
716 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
717 #endif
718 
719 #define ZONES_MASK              ((1UL << ZONES_WIDTH) - 1)
720 #define NODES_MASK              ((1UL << NODES_WIDTH) - 1)
721 #define SECTIONS_MASK           ((1UL << SECTIONS_WIDTH) - 1)
722 #define LAST_CPUPID_MASK        ((1UL << LAST_CPUPID_SHIFT) - 1)
723 #define ZONEID_MASK             ((1UL << ZONEID_SHIFT) - 1)
724 
725 static inline enum zone_type page_zonenum(const struct page *page)
726 {
727         return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
728 }
729 
730 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
731 #define SECTION_IN_PAGE_FLAGS
732 #endif
733 
734 /*
735  * The identification function is mainly used by the buddy allocator for
736  * determining if two pages could be buddies. We are not really identifying
737  * the zone since we could be using the section number id if we do not have
738  * node id available in page flags.
739  * We only guarantee that it will return the same value for two combinable
740  * pages in a zone.
741  */
742 static inline int page_zone_id(struct page *page)
743 {
744         return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
745 }
746 
747 static inline int zone_to_nid(struct zone *zone)
748 {
749 #ifdef CONFIG_NUMA
750         return zone->node;
751 #else
752         return 0;
753 #endif
754 }
755 
756 #ifdef NODE_NOT_IN_PAGE_FLAGS
757 extern int page_to_nid(const struct page *page);
758 #else
759 static inline int page_to_nid(const struct page *page)
760 {
761         return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
762 }
763 #endif
764 
765 #ifdef CONFIG_NUMA_BALANCING
766 static inline int cpu_pid_to_cpupid(int cpu, int pid)
767 {
768         return ((cpu & LAST__CPU_MASK) << LAST__PID_SHIFT) | (pid & LAST__PID_MASK);
769 }
770 
771 static inline int cpupid_to_pid(int cpupid)
772 {
773         return cpupid & LAST__PID_MASK;
774 }
775 
776 static inline int cpupid_to_cpu(int cpupid)
777 {
778         return (cpupid >> LAST__PID_SHIFT) & LAST__CPU_MASK;
779 }
780 
781 static inline int cpupid_to_nid(int cpupid)
782 {
783         return cpu_to_node(cpupid_to_cpu(cpupid));
784 }
785 
786 static inline bool cpupid_pid_unset(int cpupid)
787 {
788         return cpupid_to_pid(cpupid) == (-1 & LAST__PID_MASK);
789 }
790 
791 static inline bool cpupid_cpu_unset(int cpupid)
792 {
793         return cpupid_to_cpu(cpupid) == (-1 & LAST__CPU_MASK);
794 }
795 
796 static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
797 {
798         return (task_pid & LAST__PID_MASK) == cpupid_to_pid(cpupid);
799 }
800 
801 #define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
802 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
803 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
804 {
805         return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
806 }
807 
808 static inline int page_cpupid_last(struct page *page)
809 {
810         return page->_last_cpupid;
811 }
812 static inline void page_cpupid_reset_last(struct page *page)
813 {
814         page->_last_cpupid = -1 & LAST_CPUPID_MASK;
815 }
816 #else
817 static inline int page_cpupid_last(struct page *page)
818 {
819         return (page->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
820 }
821 
822 extern int page_cpupid_xchg_last(struct page *page, int cpupid);
823 
824 static inline void page_cpupid_reset_last(struct page *page)
825 {
826         int cpupid = (1 << LAST_CPUPID_SHIFT) - 1;
827 
828         page->flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
829         page->flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
830 }
831 #endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
832 #else /* !CONFIG_NUMA_BALANCING */
833 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
834 {
835         return page_to_nid(page); /* XXX */
836 }
837 
838 static inline int page_cpupid_last(struct page *page)
839 {
840         return page_to_nid(page); /* XXX */
841 }
842 
843 static inline int cpupid_to_nid(int cpupid)
844 {
845         return -1;
846 }
847 
848 static inline int cpupid_to_pid(int cpupid)
849 {
850         return -1;
851 }
852 
853 static inline int cpupid_to_cpu(int cpupid)
854 {
855         return -1;
856 }
857 
858 static inline int cpu_pid_to_cpupid(int nid, int pid)
859 {
860         return -1;
861 }
862 
863 static inline bool cpupid_pid_unset(int cpupid)
864 {
865         return 1;
866 }
867 
868 static inline void page_cpupid_reset_last(struct page *page)
869 {
870 }
871 
872 static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
873 {
874         return false;
875 }
876 #endif /* CONFIG_NUMA_BALANCING */
877 
878 static inline struct zone *page_zone(const struct page *page)
879 {
880         return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
881 }
882 
883 #ifdef SECTION_IN_PAGE_FLAGS
884 static inline void set_page_section(struct page *page, unsigned long section)
885 {
886         page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
887         page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
888 }
889 
890 static inline unsigned long page_to_section(const struct page *page)
891 {
892         return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
893 }
894 #endif
895 
896 static inline void set_page_zone(struct page *page, enum zone_type zone)
897 {
898         page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
899         page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
900 }
901 
902 static inline void set_page_node(struct page *page, unsigned long node)
903 {
904         page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
905         page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
906 }
907 
908 static inline void set_page_links(struct page *page, enum zone_type zone,
909         unsigned long node, unsigned long pfn)
910 {
911         set_page_zone(page, zone);
912         set_page_node(page, node);
913 #ifdef SECTION_IN_PAGE_FLAGS
914         set_page_section(page, pfn_to_section_nr(pfn));
915 #endif
916 }
917 
918 /*
919  * Some inline functions in vmstat.h depend on page_zone()
920  */
921 #include <linux/vmstat.h>
922 
923 static __always_inline void *lowmem_page_address(const struct page *page)
924 {
925         return __va(PFN_PHYS(page_to_pfn(page)));
926 }
927 
928 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
929 #define HASHED_PAGE_VIRTUAL
930 #endif
931 
932 #if defined(WANT_PAGE_VIRTUAL)
933 static inline void *page_address(const struct page *page)
934 {
935         return page->virtual;
936 }
937 static inline void set_page_address(struct page *page, void *address)
938 {
939         page->virtual = address;
940 }
941 #define page_address_init()  do { } while(0)
942 #endif
943 
944 #if defined(HASHED_PAGE_VIRTUAL)
945 void *page_address(const struct page *page);
946 void set_page_address(struct page *page, void *virtual);
947 void page_address_init(void);
948 #endif
949 
950 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
951 #define page_address(page) lowmem_page_address(page)
952 #define set_page_address(page, address)  do { } while(0)
953 #define page_address_init()  do { } while(0)
954 #endif
955 
956 extern void *page_rmapping(struct page *page);
957 extern struct anon_vma *page_anon_vma(struct page *page);
958 extern struct address_space *page_mapping(struct page *page);
959 
960 extern struct address_space *__page_file_mapping(struct page *);
961 
962 static inline
963 struct address_space *page_file_mapping(struct page *page)
964 {
965         if (unlikely(PageSwapCache(page)))
966                 return __page_file_mapping(page);
967 
968         return page->mapping;
969 }
970 
971 /*
972  * Return the pagecache index of the passed page.  Regular pagecache pages
973  * use ->index whereas swapcache pages use ->private
974  */
975 static inline pgoff_t page_index(struct page *page)
976 {
977         if (unlikely(PageSwapCache(page)))
978                 return page_private(page);
979         return page->index;
980 }
981 
982 extern pgoff_t __page_file_index(struct page *page);
983 
984 /*
985  * Return the file index of the page. Regular pagecache pages use ->index
986  * whereas swapcache pages use swp_offset(->private)
987  */
988 static inline pgoff_t page_file_index(struct page *page)
989 {
990         if (unlikely(PageSwapCache(page)))
991                 return __page_file_index(page);
992 
993         return page->index;
994 }
995 
996 /*
997  * Return true if this page is mapped into pagetables.
998  */
999 static inline int page_mapped(struct page *page)
1000 {
1001         return atomic_read(&(page)->_mapcount) >= 0;
1002 }
1003 
1004 /*
1005  * Different kinds of faults, as returned by handle_mm_fault().
1006  * Used to decide whether a process gets delivered SIGBUS or
1007  * just gets major/minor fault counters bumped up.
1008  */
1009 
1010 #define VM_FAULT_MINOR  0 /* For backwards compat. Remove me quickly. */
1011 
1012 #define VM_FAULT_OOM    0x0001
1013 #define VM_FAULT_SIGBUS 0x0002
1014 #define VM_FAULT_MAJOR  0x0004
1015 #define VM_FAULT_WRITE  0x0008  /* Special case for get_user_pages */
1016 #define VM_FAULT_HWPOISON 0x0010        /* Hit poisoned small page */
1017 #define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
1018 #define VM_FAULT_SIGSEGV 0x0040
1019 
1020 #define VM_FAULT_NOPAGE 0x0100  /* ->fault installed the pte, not return page */
1021 #define VM_FAULT_LOCKED 0x0200  /* ->fault locked the returned page */
1022 #define VM_FAULT_RETRY  0x0400  /* ->fault blocked, must retry */
1023 #define VM_FAULT_FALLBACK 0x0800        /* huge page fault failed, fall back to small */
1024 
1025 #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */
1026 
1027 #define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \
1028                          VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \
1029                          VM_FAULT_FALLBACK)
1030 
1031 /* Encode hstate index for a hwpoisoned large page */
1032 #define VM_FAULT_SET_HINDEX(x) ((x) << 12)
1033 #define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
1034 
1035 /*
1036  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
1037  */
1038 extern void pagefault_out_of_memory(void);
1039 
1040 #define offset_in_page(p)       ((unsigned long)(p) & ~PAGE_MASK)
1041 
1042 /*
1043  * Flags passed to show_mem() and show_free_areas() to suppress output in
1044  * various contexts.
1045  */
1046 #define SHOW_MEM_FILTER_NODES           (0x0001u)       /* disallowed nodes */
1047 
1048 extern void show_free_areas(unsigned int flags);
1049 extern bool skip_free_areas_node(unsigned int flags, int nid);
1050 
1051 int shmem_zero_setup(struct vm_area_struct *);
1052 #ifdef CONFIG_SHMEM
1053 bool shmem_mapping(struct address_space *mapping);
1054 #else
1055 static inline bool shmem_mapping(struct address_space *mapping)
1056 {
1057         return false;
1058 }
1059 #endif
1060 
1061 extern int can_do_mlock(void);
1062 extern int user_shm_lock(size_t, struct user_struct *);
1063 extern void user_shm_unlock(size_t, struct user_struct *);
1064 
1065 /*
1066  * Parameter block passed down to zap_pte_range in exceptional cases.
1067  */
1068 struct zap_details {
1069         struct address_space *check_mapping;    /* Check page->mapping if set */
1070         pgoff_t first_index;                    /* Lowest page->index to unmap */
1071         pgoff_t last_index;                     /* Highest page->index to unmap */
1072 };
1073 
1074 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
1075                 pte_t pte);
1076 
1077 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1078                 unsigned long size);
1079 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
1080                 unsigned long size, struct zap_details *);
1081 void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
1082                 unsigned long start, unsigned long end);
1083 
1084 /**
1085  * mm_walk - callbacks for walk_page_range
1086  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
1087  *             this handler is required to be able to handle
1088  *             pmd_trans_huge() pmds.  They may simply choose to
1089  *             split_huge_page() instead of handling it explicitly.
1090  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
1091  * @pte_hole: if set, called for each hole at all levels
1092  * @hugetlb_entry: if set, called for each hugetlb entry
1093  * @test_walk: caller specific callback function to determine whether
1094  *             we walk over the current vma or not. A positive returned
1095  *             value means "do page table walk over the current vma,"
1096  *             and a negative one means "abort current page table walk
1097  *             right now." 0 means "skip the current vma."
1098  * @mm:        mm_struct representing the target process of page table walk
1099  * @vma:       vma currently walked (NULL if walking outside vmas)
1100  * @private:   private data for callbacks' usage
1101  *
1102  * (see the comment on walk_page_range() for more details)
1103  */
1104 struct mm_walk {
1105         int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
1106                          unsigned long next, struct mm_walk *walk);
1107         int (*pte_entry)(pte_t *pte, unsigned long addr,
1108                          unsigned long next, struct mm_walk *walk);
1109         int (*pte_hole)(unsigned long addr, unsigned long next,
1110                         struct mm_walk *walk);
1111         int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
1112                              unsigned long addr, unsigned long next,
1113                              struct mm_walk *walk);
1114         int (*test_walk)(unsigned long addr, unsigned long next,
1115                         struct mm_walk *walk);
1116         struct mm_struct *mm;
1117         struct vm_area_struct *vma;
1118         void *private;
1119 };
1120 
1121 int walk_page_range(unsigned long addr, unsigned long end,
1122                 struct mm_walk *walk);
1123 int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
1124 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
1125                 unsigned long end, unsigned long floor, unsigned long ceiling);
1126 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
1127                         struct vm_area_struct *vma);
1128 void unmap_mapping_range(struct address_space *mapping,
1129                 loff_t const holebegin, loff_t const holelen, int even_cows);
1130 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
1131         unsigned long *pfn);
1132 int follow_phys(struct vm_area_struct *vma, unsigned long address,
1133                 unsigned int flags, unsigned long *prot, resource_size_t *phys);
1134 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
1135                         void *buf, int len, int write);
1136 
1137 static inline void unmap_shared_mapping_range(struct address_space *mapping,
1138                 loff_t const holebegin, loff_t const holelen)
1139 {
1140         unmap_mapping_range(mapping, holebegin, holelen, 0);
1141 }
1142 
1143 extern void truncate_pagecache(struct inode *inode, loff_t new);
1144 extern void truncate_setsize(struct inode *inode, loff_t newsize);
1145 void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to);
1146 void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end);
1147 int truncate_inode_page(struct address_space *mapping, struct page *page);
1148 int generic_error_remove_page(struct address_space *mapping, struct page *page);
1149 int invalidate_inode_page(struct page *page);
1150 
1151 #ifdef CONFIG_MMU
1152 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
1153                         unsigned long address, unsigned int flags);
1154 extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1155                             unsigned long address, unsigned int fault_flags);
1156 #else
1157 static inline int handle_mm_fault(struct mm_struct *mm,
1158                         struct vm_area_struct *vma, unsigned long address,
1159                         unsigned int flags)
1160 {
1161         /* should never happen if there's no MMU */
1162         BUG();
1163         return VM_FAULT_SIGBUS;
1164 }
1165 static inline int fixup_user_fault(struct task_struct *tsk,
1166                 struct mm_struct *mm, unsigned long address,
1167                 unsigned int fault_flags)
1168 {
1169         /* should never happen if there's no MMU */
1170         BUG();
1171         return -EFAULT;
1172 }
1173 #endif
1174 
1175 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
1176 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1177                 void *buf, int len, int write);
1178 
1179 long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1180                       unsigned long start, unsigned long nr_pages,
1181                       unsigned int foll_flags, struct page **pages,
1182                       struct vm_area_struct **vmas, int *nonblocking);
1183 long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1184                     unsigned long start, unsigned long nr_pages,
1185                     int write, int force, struct page **pages,
1186                     struct vm_area_struct **vmas);
1187 long get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm,
1188                     unsigned long start, unsigned long nr_pages,
1189                     int write, int force, struct page **pages,
1190                     int *locked);
1191 long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
1192                                unsigned long start, unsigned long nr_pages,
1193                                int write, int force, struct page **pages,
1194                                unsigned int gup_flags);
1195 long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
1196                     unsigned long start, unsigned long nr_pages,
1197                     int write, int force, struct page **pages);
1198 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
1199                         struct page **pages);
1200 struct kvec;
1201 int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
1202                         struct page **pages);
1203 int get_kernel_page(unsigned long start, int write, struct page **pages);
1204 struct page *get_dump_page(unsigned long addr);
1205 
1206 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
1207 extern void do_invalidatepage(struct page *page, unsigned int offset,
1208                               unsigned int length);
1209 
1210 int __set_page_dirty_nobuffers(struct page *page);
1211 int __set_page_dirty_no_writeback(struct page *page);
1212 int redirty_page_for_writepage(struct writeback_control *wbc,
1213                                 struct page *page);
1214 void account_page_dirtied(struct page *page, struct address_space *mapping);
1215 void account_page_cleaned(struct page *page, struct address_space *mapping);
1216 int set_page_dirty(struct page *page);
1217 int set_page_dirty_lock(struct page *page);
1218 int clear_page_dirty_for_io(struct page *page);
1219 
1220 int get_cmdline(struct task_struct *task, char *buffer, int buflen);
1221 
1222 /* Is the vma a continuation of the stack vma above it? */
1223 static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
1224 {
1225         return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
1226 }
1227 
1228 static inline int stack_guard_page_start(struct vm_area_struct *vma,
1229                                              unsigned long addr)
1230 {
1231         return (vma->vm_flags & VM_GROWSDOWN) &&
1232                 (vma->vm_start == addr) &&
1233                 !vma_growsdown(vma->vm_prev, addr);
1234 }
1235 
1236 /* Is the vma a continuation of the stack vma below it? */
1237 static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
1238 {
1239         return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
1240 }
1241 
1242 static inline int stack_guard_page_end(struct vm_area_struct *vma,
1243                                            unsigned long addr)
1244 {
1245         return (vma->vm_flags & VM_GROWSUP) &&
1246                 (vma->vm_end == addr) &&
1247                 !vma_growsup(vma->vm_next, addr);
1248 }
1249 
1250 extern struct task_struct *task_of_stack(struct task_struct *task,
1251                                 struct vm_area_struct *vma, bool in_group);
1252 
1253 extern unsigned long move_page_tables(struct vm_area_struct *vma,
1254                 unsigned long old_addr, struct vm_area_struct *new_vma,
1255                 unsigned long new_addr, unsigned long len,
1256                 bool need_rmap_locks);
1257 extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
1258                               unsigned long end, pgprot_t newprot,
1259                               int dirty_accountable, int prot_numa);
1260 extern int mprotect_fixup(struct vm_area_struct *vma,
1261                           struct vm_area_struct **pprev, unsigned long start,
1262                           unsigned long end, unsigned long newflags);
1263 
1264 /*
1265  * doesn't attempt to fault and will return short.
1266  */
1267 int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
1268                           struct page **pages);
1269 /*
1270  * per-process(per-mm_struct) statistics.
1271  */
1272 static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
1273 {
1274         long val = atomic_long_read(&mm->rss_stat.count[member]);
1275 
1276 #ifdef SPLIT_RSS_COUNTING
1277         /*
1278          * counter is updated in asynchronous manner and may go to minus.
1279          * But it's never be expected number for users.
1280          */
1281         if (val < 0)
1282                 val = 0;
1283 #endif
1284         return (unsigned long)val;
1285 }
1286 
1287 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
1288 {
1289         atomic_long_add(value, &mm->rss_stat.count[member]);
1290 }
1291 
1292 static inline void inc_mm_counter(struct mm_struct *mm, int member)
1293 {
1294         atomic_long_inc(&mm->rss_stat.count[member]);
1295 }
1296 
1297 static inline void dec_mm_counter(struct mm_struct *mm, int member)
1298 {
1299         atomic_long_dec(&mm->rss_stat.count[member]);
1300 }
1301 
1302 static inline unsigned long get_mm_rss(struct mm_struct *mm)
1303 {
1304         return get_mm_counter(mm, MM_FILEPAGES) +
1305                 get_mm_counter(mm, MM_ANONPAGES);
1306 }
1307 
1308 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
1309 {
1310         return max(mm->hiwater_rss, get_mm_rss(mm));
1311 }
1312 
1313 static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
1314 {
1315         return max(mm->hiwater_vm, mm->total_vm);
1316 }
1317 
1318 static inline void update_hiwater_rss(struct mm_struct *mm)
1319 {
1320         unsigned long _rss = get_mm_rss(mm);
1321 
1322         if ((mm)->hiwater_rss < _rss)
1323                 (mm)->hiwater_rss = _rss;
1324 }
1325 
1326 static inline void update_hiwater_vm(struct mm_struct *mm)
1327 {
1328         if (mm->hiwater_vm < mm->total_vm)
1329                 mm->hiwater_vm = mm->total_vm;
1330 }
1331 
1332 static inline void reset_mm_hiwater_rss(struct mm_struct *mm)
1333 {
1334         mm->hiwater_rss = get_mm_rss(mm);
1335 }
1336 
1337 static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
1338                                          struct mm_struct *mm)
1339 {
1340         unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
1341 
1342         if (*maxrss < hiwater_rss)
1343                 *maxrss = hiwater_rss;
1344 }
1345 
1346 #if defined(SPLIT_RSS_COUNTING)
1347 void sync_mm_rss(struct mm_struct *mm);
1348 #else
1349 static inline void sync_mm_rss(struct mm_struct *mm)
1350 {
1351 }
1352 #endif
1353 
1354 int vma_wants_writenotify(struct vm_area_struct *vma);
1355 
1356 extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1357                                spinlock_t **ptl);
1358 static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1359                                     spinlock_t **ptl)
1360 {
1361         pte_t *ptep;
1362         __cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
1363         return ptep;
1364 }
1365 
1366 #ifdef __PAGETABLE_PUD_FOLDED
1367 static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
1368                                                 unsigned long address)
1369 {
1370         return 0;
1371 }
1372 #else
1373 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
1374 #endif
1375 
1376 #if defined(__PAGETABLE_PMD_FOLDED) || !defined(CONFIG_MMU)
1377 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
1378                                                 unsigned long address)
1379 {
1380         return 0;
1381 }
1382 
1383 static inline void mm_nr_pmds_init(struct mm_struct *mm) {}
1384 
1385 static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
1386 {
1387         return 0;
1388 }
1389 
1390 static inline void mm_inc_nr_pmds(struct mm_struct *mm) {}
1391 static inline void mm_dec_nr_pmds(struct mm_struct *mm) {}
1392 
1393 #else
1394 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
1395 
1396 static inline void mm_nr_pmds_init(struct mm_struct *mm)
1397 {
1398         atomic_long_set(&mm->nr_pmds, 0);
1399 }
1400 
1401 static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
1402 {
1403         return atomic_long_read(&mm->nr_pmds);
1404 }
1405 
1406 static inline void mm_inc_nr_pmds(struct mm_struct *mm)
1407 {
1408         atomic_long_inc(&mm->nr_pmds);
1409 }
1410 
1411 static inline void mm_dec_nr_pmds(struct mm_struct *mm)
1412 {
1413         atomic_long_dec(&mm->nr_pmds);
1414 }
1415 #endif
1416 
1417 int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
1418                 pmd_t *pmd, unsigned long address);
1419 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
1420 
1421 /*
1422  * The following ifdef needed to get the 4level-fixup.h header to work.
1423  * Remove it when 4level-fixup.h has been removed.
1424  */
1425 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
1426 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
1427 {
1428         return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
1429                 NULL: pud_offset(pgd, address);
1430 }
1431 
1432 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
1433 {
1434         return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
1435                 NULL: pmd_offset(pud, address);
1436 }
1437 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
1438 
1439 #if USE_SPLIT_PTE_PTLOCKS
1440 #if ALLOC_SPLIT_PTLOCKS
1441 void __init ptlock_cache_init(void);
1442 extern bool ptlock_alloc(struct page *page);
1443 extern void ptlock_free(struct page *page);
1444 
1445 static inline spinlock_t *ptlock_ptr(struct page *page)
1446 {
1447         return page->ptl;
1448 }
1449 #else /* ALLOC_SPLIT_PTLOCKS */
1450 static inline void ptlock_cache_init(void)
1451 {
1452 }
1453 
1454 static inline bool ptlock_alloc(struct page *page)
1455 {
1456         return true;
1457 }
1458 
1459 static inline void ptlock_free(struct page *page)
1460 {
1461 }
1462 
1463 static inline spinlock_t *ptlock_ptr(struct page *page)
1464 {
1465         return &page->ptl;
1466 }
1467 #endif /* ALLOC_SPLIT_PTLOCKS */
1468 
1469 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1470 {
1471         return ptlock_ptr(pmd_page(*pmd));
1472 }
1473 
1474 static inline bool ptlock_init(struct page *page)
1475 {
1476         /*
1477          * prep_new_page() initialize page->private (and therefore page->ptl)
1478          * with 0. Make sure nobody took it in use in between.
1479          *
1480          * It can happen if arch try to use slab for page table allocation:
1481          * slab code uses page->slab_cache and page->first_page (for tail
1482          * pages), which share storage with page->ptl.
1483          */
1484         VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
1485         if (!ptlock_alloc(page))
1486                 return false;
1487         spin_lock_init(ptlock_ptr(page));
1488         return true;
1489 }
1490 
1491 /* Reset page->mapping so free_pages_check won't complain. */
1492 static inline void pte_lock_deinit(struct page *page)
1493 {
1494         page->mapping = NULL;
1495         ptlock_free(page);
1496 }
1497 
1498 #else   /* !USE_SPLIT_PTE_PTLOCKS */
1499 /*
1500  * We use mm->page_table_lock to guard all pagetable pages of the mm.
1501  */
1502 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1503 {
1504         return &mm->page_table_lock;
1505 }
1506 static inline void ptlock_cache_init(void) {}
1507 static inline bool ptlock_init(struct page *page) { return true; }
1508 static inline void pte_lock_deinit(struct page *page) {}
1509 #endif /* USE_SPLIT_PTE_PTLOCKS */
1510 
1511 static inline void pgtable_init(void)
1512 {
1513         ptlock_cache_init();
1514         pgtable_cache_init();
1515 }
1516 
1517 static inline bool pgtable_page_ctor(struct page *page)
1518 {
1519         inc_zone_page_state(page, NR_PAGETABLE);
1520         return ptlock_init(page);
1521 }
1522 
1523 static inline void pgtable_page_dtor(struct page *page)
1524 {
1525         pte_lock_deinit(page);
1526         dec_zone_page_state(page, NR_PAGETABLE);
1527 }
1528 
1529 #define pte_offset_map_lock(mm, pmd, address, ptlp)     \
1530 ({                                                      \
1531         spinlock_t *__ptl = pte_lockptr(mm, pmd);       \
1532         pte_t *__pte = pte_offset_map(pmd, address);    \
1533         *(ptlp) = __ptl;                                \
1534         spin_lock(__ptl);                               \
1535         __pte;                                          \
1536 })
1537 
1538 #define pte_unmap_unlock(pte, ptl)      do {            \
1539         spin_unlock(ptl);                               \
1540         pte_unmap(pte);                                 \
1541 } while (0)
1542 
1543 #define pte_alloc_map(mm, vma, pmd, address)                            \
1544         ((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, vma,    \
1545                                                         pmd, address))? \
1546          NULL: pte_offset_map(pmd, address))
1547 
1548 #define pte_alloc_map_lock(mm, pmd, address, ptlp)      \
1549         ((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, NULL,   \
1550                                                         pmd, address))? \
1551                 NULL: pte_offset_map_lock(mm, pmd, address, ptlp))
1552 
1553 #define pte_alloc_kernel(pmd, address)                  \
1554         ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
1555                 NULL: pte_offset_kernel(pmd, address))
1556 
1557 #if USE_SPLIT_PMD_PTLOCKS
1558 
1559 static struct page *pmd_to_page(pmd_t *pmd)
1560 {
1561         unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
1562         return virt_to_page((void *)((unsigned long) pmd & mask));
1563 }
1564 
1565 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1566 {
1567         return ptlock_ptr(pmd_to_page(pmd));
1568 }
1569 
1570 static inline bool pgtable_pmd_page_ctor(struct page *page)
1571 {
1572 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1573         page->pmd_huge_pte = NULL;
1574 #endif
1575         return ptlock_init(page);
1576 }
1577 
1578 static inline void pgtable_pmd_page_dtor(struct page *page)
1579 {
1580 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1581         VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
1582 #endif
1583         ptlock_free(page);
1584 }
1585 
1586 #define pmd_huge_pte(mm, pmd) (pmd_to_page(pmd)->pmd_huge_pte)
1587 
1588 #else
1589 
1590 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1591 {
1592         return &mm->page_table_lock;
1593 }
1594 
1595 static inline bool pgtable_pmd_page_ctor(struct page *page) { return true; }
1596 static inline void pgtable_pmd_page_dtor(struct page *page) {}
1597 
1598 #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
1599 
1600 #endif
1601 
1602 static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
1603 {
1604         spinlock_t *ptl = pmd_lockptr(mm, pmd);
1605         spin_lock(ptl);
1606         return ptl;
1607 }
1608 
1609 extern void free_area_init(unsigned long * zones_size);
1610 extern void free_area_init_node(int nid, unsigned long * zones_size,
1611                 unsigned long zone_start_pfn, unsigned long *zholes_size);
1612 extern void free_initmem(void);
1613 
1614 /*
1615  * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
1616  * into the buddy system. The freed pages will be poisoned with pattern
1617  * "poison" if it's within range [0, UCHAR_MAX].
1618  * Return pages freed into the buddy system.
1619  */
1620 extern unsigned long free_reserved_area(void *start, void *end,
1621                                         int poison, char *s);
1622 
1623 #ifdef  CONFIG_HIGHMEM
1624 /*
1625  * Free a highmem page into the buddy system, adjusting totalhigh_pages
1626  * and totalram_pages.
1627  */
1628 extern void free_highmem_page(struct page *page);
1629 #endif
1630 
1631 extern void adjust_managed_page_count(struct page *page, long count);
1632 extern void mem_init_print_info(const char *str);
1633 
1634 /* Free the reserved page into the buddy system, so it gets managed. */
1635 static inline void __free_reserved_page(struct page *page)
1636 {
1637         ClearPageReserved(page);
1638         init_page_count(page);
1639         __free_page(page);
1640 }
1641 
1642 static inline void free_reserved_page(struct page *page)
1643 {
1644         __free_reserved_page(page);
1645         adjust_managed_page_count(page, 1);
1646 }
1647 
1648 static inline void mark_page_reserved(struct page *page)
1649 {
1650         SetPageReserved(page);
1651         adjust_managed_page_count(page, -1);
1652 }
1653 
1654 /*
1655  * Default method to free all the __init memory into the buddy system.
1656  * The freed pages will be poisoned with pattern "poison" if it's within
1657  * range [0, UCHAR_MAX].
1658  * Return pages freed into the buddy system.
1659  */
1660 static inline unsigned long free_initmem_default(int poison)
1661 {
1662         extern char __init_begin[], __init_end[];
1663 
1664         return free_reserved_area(&__init_begin, &__init_end,
1665                                   poison, "unused kernel");
1666 }
1667 
1668 static inline unsigned long get_num_physpages(void)
1669 {
1670         int nid;
1671         unsigned long phys_pages = 0;
1672 
1673         for_each_online_node(nid)
1674                 phys_pages += node_present_pages(nid);
1675 
1676         return phys_pages;
1677 }
1678 
1679 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1680 /*
1681  * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
1682  * zones, allocate the backing mem_map and account for memory holes in a more
1683  * architecture independent manner. This is a substitute for creating the
1684  * zone_sizes[] and zholes_size[] arrays and passing them to
1685  * free_area_init_node()
1686  *
1687  * An architecture is expected to register range of page frames backed by
1688  * physical memory with memblock_add[_node]() before calling
1689  * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
1690  * usage, an architecture is expected to do something like
1691  *
1692  * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
1693  *                                                       max_highmem_pfn};
1694  * for_each_valid_physical_page_range()
1695  *      memblock_add_node(base, size, nid)
1696  * free_area_init_nodes(max_zone_pfns);
1697  *
1698  * free_bootmem_with_active_regions() calls free_bootmem_node() for each
1699  * registered physical page range.  Similarly
1700  * sparse_memory_present_with_active_regions() calls memory_present() for
1701  * each range when SPARSEMEM is enabled.
1702  *
1703  * See mm/page_alloc.c for more information on each function exposed by
1704  * CONFIG_HAVE_MEMBLOCK_NODE_MAP.
1705  */
1706 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
1707 unsigned long node_map_pfn_alignment(void);
1708 unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
1709                                                 unsigned long end_pfn);
1710 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
1711                                                 unsigned long end_pfn);
1712 extern void get_pfn_range_for_nid(unsigned int nid,
1713                         unsigned long *start_pfn, unsigned long *end_pfn);
1714 extern unsigned long find_min_pfn_with_active_regions(void);
1715 extern void free_bootmem_with_active_regions(int nid,
1716                                                 unsigned long max_low_pfn);
1717 extern void sparse_memory_present_with_active_regions(int nid);
1718 
1719 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
1720 
1721 #if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
1722     !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
1723 static inline int __early_pfn_to_nid(unsigned long pfn)
1724 {
1725         return 0;
1726 }
1727 #else
1728 /* please see mm/page_alloc.c */
1729 extern int __meminit early_pfn_to_nid(unsigned long pfn);
1730 /* there is a per-arch backend function. */
1731 extern int __meminit __early_pfn_to_nid(unsigned long pfn);
1732 #endif
1733 
1734 extern void set_dma_reserve(unsigned long new_dma_reserve);
1735 extern void memmap_init_zone(unsigned long, int, unsigned long,
1736                                 unsigned long, enum memmap_context);
1737 extern void setup_per_zone_wmarks(void);
1738 extern int __meminit init_per_zone_wmark_min(void);
1739 extern void mem_init(void);
1740 extern void __init mmap_init(void);
1741 extern void show_mem(unsigned int flags);
1742 extern void si_meminfo(struct sysinfo * val);
1743 extern void si_meminfo_node(struct sysinfo *val, int nid);
1744 
1745 extern __printf(3, 4)
1746 void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...);
1747 
1748 extern void setup_per_cpu_pageset(void);
1749 
1750 extern void zone_pcp_update(struct zone *zone);
1751 extern void zone_pcp_reset(struct zone *zone);
1752 
1753 /* page_alloc.c */
1754 extern int min_free_kbytes;
1755 
1756 /* nommu.c */
1757 extern atomic_long_t mmap_pages_allocated;
1758 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
1759 
1760 /* interval_tree.c */
1761 void vma_interval_tree_insert(struct vm_area_struct *node,
1762                               struct rb_root *root);
1763 void vma_interval_tree_insert_after(struct vm_area_struct *node,
1764                                     struct vm_area_struct *prev,
1765                                     struct rb_root *root);
1766 void vma_interval_tree_remove(struct vm_area_struct *node,
1767                               struct rb_root *root);
1768 struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root *root,
1769                                 unsigned long start, unsigned long last);
1770 struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
1771                                 unsigned long start, unsigned long last);
1772 
1773 #define vma_interval_tree_foreach(vma, root, start, last)               \
1774         for (vma = vma_interval_tree_iter_first(root, start, last);     \
1775              vma; vma = vma_interval_tree_iter_next(vma, start, last))
1776 
1777 void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
1778                                    struct rb_root *root);
1779 void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
1780                                    struct rb_root *root);
1781 struct anon_vma_chain *anon_vma_interval_tree_iter_first(
1782         struct rb_root *root, unsigned long start, unsigned long last);
1783 struct anon_vma_chain *anon_vma_interval_tree_iter_next(
1784         struct anon_vma_chain *node, unsigned long start, unsigned long last);
1785 #ifdef CONFIG_DEBUG_VM_RB
1786 void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
1787 #endif
1788 
1789 #define anon_vma_interval_tree_foreach(avc, root, start, last)           \
1790         for (avc = anon_vma_interval_tree_iter_first(root, start, last); \
1791              avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
1792 
1793 /* mmap.c */
1794 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
1795 extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
1796         unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
1797 extern struct vm_area_struct *vma_merge(struct mm_struct *,
1798         struct vm_area_struct *prev, unsigned long addr, unsigned long end,
1799         unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
1800         struct mempolicy *);
1801 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
1802 extern int split_vma(struct mm_struct *,
1803         struct vm_area_struct *, unsigned long addr, int new_below);
1804 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
1805 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
1806         struct rb_node **, struct rb_node *);
1807 extern void unlink_file_vma(struct vm_area_struct *);
1808 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
1809         unsigned long addr, unsigned long len, pgoff_t pgoff,
1810         bool *need_rmap_locks);
1811 extern void exit_mmap(struct mm_struct *);
1812 
1813 static inline int check_data_rlimit(unsigned long rlim,
1814                                     unsigned long new,
1815                                     unsigned long start,
1816                                     unsigned long end_data,
1817                                     unsigned long start_data)
1818 {
1819         if (rlim < RLIM_INFINITY) {
1820                 if (((new - start) + (end_data - start_data)) > rlim)
1821                         return -ENOSPC;
1822         }
1823 
1824         return 0;
1825 }
1826 
1827 extern int mm_take_all_locks(struct mm_struct *mm);
1828 extern void mm_drop_all_locks(struct mm_struct *mm);
1829 
1830 extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
1831 extern struct file *get_mm_exe_file(struct mm_struct *mm);
1832 
1833 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
1834 extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
1835                                    unsigned long addr, unsigned long len,
1836                                    unsigned long flags,
1837                                    const struct vm_special_mapping *spec);
1838 /* This is an obsolete alternative to _install_special_mapping. */
1839 extern int install_special_mapping(struct mm_struct *mm,
1840                                    unsigned long addr, unsigned long len,
1841                                    unsigned long flags, struct page **pages);
1842 
1843 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1844 
1845 extern unsigned long mmap_region(struct file *file, unsigned long addr,
1846         unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
1847 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
1848         unsigned long len, unsigned long prot, unsigned long flags,
1849         unsigned long pgoff, unsigned long *populate);
1850 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
1851 
1852 #ifdef CONFIG_MMU
1853 extern int __mm_populate(unsigned long addr, unsigned long len,
1854                          int ignore_errors);
1855 static inline void mm_populate(unsigned long addr, unsigned long len)
1856 {
1857         /* Ignore errors */
1858         (void) __mm_populate(addr, len, 1);
1859 }
1860 #else
1861 static inline void mm_populate(unsigned long addr, unsigned long len) {}
1862 #endif
1863 
1864 /* These take the mm semaphore themselves */
1865 extern unsigned long vm_brk(unsigned long, unsigned long);
1866 extern int vm_munmap(unsigned long, size_t);
1867 extern unsigned long vm_mmap(struct file *, unsigned long,
1868         unsigned long, unsigned long,
1869         unsigned long, unsigned long);
1870 
1871 struct vm_unmapped_area_info {
1872 #define VM_UNMAPPED_AREA_TOPDOWN 1
1873         unsigned long flags;
1874         unsigned long length;
1875         unsigned long low_limit;
1876         unsigned long high_limit;
1877         unsigned long align_mask;
1878         unsigned long align_offset;
1879 };
1880 
1881 extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
1882 extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
1883 
1884 /*
1885  * Search for an unmapped address range.
1886  *
1887  * We are looking for a range that:
1888  * - does not intersect with any VMA;
1889  * - is contained within the [low_limit, high_limit) interval;
1890  * - is at least the desired size.
1891  * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
1892  */
1893 static inline unsigned long
1894 vm_unmapped_area(struct vm_unmapped_area_info *info)
1895 {
1896         if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
1897                 return unmapped_area_topdown(info);
1898         else
1899                 return unmapped_area(info);
1900 }
1901 
1902 /* truncate.c */
1903 extern void truncate_inode_pages(struct address_space *, loff_t);
1904 extern void truncate_inode_pages_range(struct address_space *,
1905                                        loff_t lstart, loff_t lend);
1906 extern void truncate_inode_pages_final(struct address_space *);
1907 
1908 /* generic vm_area_ops exported for stackable file systems */
1909 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
1910 extern void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf);
1911 extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
1912 
1913 /* mm/page-writeback.c */
1914 int write_one_page(struct page *page, int wait);
1915 void task_dirty_inc(struct task_struct *tsk);
1916 
1917 /* readahead.c */
1918 #define VM_MAX_READAHEAD        128     /* kbytes */
1919 #define VM_MIN_READAHEAD        16      /* kbytes (includes current page) */
1920 
1921 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
1922                         pgoff_t offset, unsigned long nr_to_read);
1923 
1924 void page_cache_sync_readahead(struct address_space *mapping,
1925                                struct file_ra_state *ra,
1926                                struct file *filp,
1927                                pgoff_t offset,
1928                                unsigned long size);
1929 
1930 void page_cache_async_readahead(struct address_space *mapping,
1931                                 struct file_ra_state *ra,
1932                                 struct file *filp,
1933                                 struct page *pg,
1934                                 pgoff_t offset,
1935                                 unsigned long size);
1936 
1937 unsigned long max_sane_readahead(unsigned long nr);
1938 
1939 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
1940 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
1941 
1942 /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
1943 extern int expand_downwards(struct vm_area_struct *vma,
1944                 unsigned long address);
1945 #if VM_GROWSUP
1946 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
1947 #else
1948   #define expand_upwards(vma, address) (0)
1949 #endif
1950 
1951 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
1952 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
1953 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
1954                                              struct vm_area_struct **pprev);
1955 
1956 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
1957    NULL if none.  Assume start_addr < end_addr. */
1958 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
1959 {
1960         struct vm_area_struct * vma = find_vma(mm,start_addr);
1961 
1962         if (vma && end_addr <= vma->vm_start)
1963                 vma = NULL;
1964         return vma;
1965 }
1966 
1967 static inline unsigned long vma_pages(struct vm_area_struct *vma)
1968 {
1969         return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
1970 }
1971 
1972 /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
1973 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
1974                                 unsigned long vm_start, unsigned long vm_end)
1975 {
1976         struct vm_area_struct *vma = find_vma(mm, vm_start);
1977 
1978         if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
1979                 vma = NULL;
1980 
1981         return vma;
1982 }
1983 
1984 #ifdef CONFIG_MMU
1985 pgprot_t vm_get_page_prot(unsigned long vm_flags);
1986 void vma_set_page_prot(struct vm_area_struct *vma);
1987 #else
1988 static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
1989 {
1990         return __pgprot(0);
1991 }
1992 static inline void vma_set_page_prot(struct vm_area_struct *vma)
1993 {
1994         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
1995 }
1996 #endif
1997 
1998 #ifdef CONFIG_NUMA_BALANCING
1999 unsigned long change_prot_numa(struct vm_area_struct *vma,
2000                         unsigned long start, unsigned long end);
2001 #endif
2002 
2003 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
2004 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
2005                         unsigned long pfn, unsigned long size, pgprot_t);
2006 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
2007 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2008                         unsigned long pfn);
2009 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2010                         unsigned long pfn);
2011 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
2012 
2013 
2014 struct page *follow_page_mask(struct vm_area_struct *vma,
2015                               unsigned long address, unsigned int foll_flags,
2016                               unsigned int *page_mask);
2017 
2018 static inline struct page *follow_page(struct vm_area_struct *vma,
2019                 unsigned long address, unsigned int foll_flags)
2020 {
2021         unsigned int unused_page_mask;
2022         return follow_page_mask(vma, address, foll_flags, &unused_page_mask);
2023 }
2024 
2025 #define FOLL_WRITE      0x01    /* check pte is writable */
2026 #define FOLL_TOUCH      0x02    /* mark page accessed */
2027 #define FOLL_GET        0x04    /* do get_page on page */
2028 #define FOLL_DUMP       0x08    /* give error on hole if it would be zero */
2029 #define FOLL_FORCE      0x10    /* get_user_pages read/write w/o permission */
2030 #define FOLL_NOWAIT     0x20    /* if a disk transfer is needed, start the IO
2031                                  * and return without waiting upon it */
2032 #define FOLL_POPULATE   0x40    /* fault in page */
2033 #define FOLL_SPLIT      0x80    /* don't return transhuge pages, split them */
2034 #define FOLL_HWPOISON   0x100   /* check page is hwpoisoned */
2035 #define FOLL_NUMA       0x200   /* force NUMA hinting page fault */
2036 #define FOLL_MIGRATION  0x400   /* wait for page to replace migration entry */
2037 #define FOLL_TRIED      0x800   /* a retry, previous pass started an IO */
2038 
2039 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
2040                         void *data);
2041 extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
2042                                unsigned long size, pte_fn_t fn, void *data);
2043 
2044 #ifdef CONFIG_PROC_FS
2045 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
2046 #else
2047 static inline void vm_stat_account(struct mm_struct *mm,
2048                         unsigned long flags, struct file *file, long pages)
2049 {
2050         mm->total_vm += pages;
2051 }
2052 #endif /* CONFIG_PROC_FS */
2053 
2054 #ifdef CONFIG_DEBUG_PAGEALLOC
2055 extern bool _debug_pagealloc_enabled;
2056 extern void __kernel_map_pages(struct page *page, int numpages, int enable);
2057 
2058 static inline bool debug_pagealloc_enabled(void)
2059 {
2060         return _debug_pagealloc_enabled;
2061 }
2062 
2063 static inline void
2064 kernel_map_pages(struct page *page, int numpages, int enable)
2065 {
2066         if (!debug_pagealloc_enabled())
2067                 return;
2068 
2069         __kernel_map_pages(page, numpages, enable);
2070 }
2071 #ifdef CONFIG_HIBERNATION
2072 extern bool kernel_page_present(struct page *page);
2073 #endif /* CONFIG_HIBERNATION */
2074 #else
2075 static inline void
2076 kernel_map_pages(struct page *page, int numpages, int enable) {}
2077 #ifdef CONFIG_HIBERNATION
2078 static inline bool kernel_page_present(struct page *page) { return true; }
2079 #endif /* CONFIG_HIBERNATION */
2080 #endif
2081 
2082 #ifdef __HAVE_ARCH_GATE_AREA
2083 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
2084 extern int in_gate_area_no_mm(unsigned long addr);
2085 extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
2086 #else
2087 static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
2088 {
2089         return NULL;
2090 }
2091 static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
2092 static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
2093 {
2094         return 0;
2095 }
2096 #endif  /* __HAVE_ARCH_GATE_AREA */
2097 
2098 #ifdef CONFIG_SYSCTL
2099 extern int sysctl_drop_caches;
2100 int drop_caches_sysctl_handler(struct ctl_table *, int,
2101                                         void __user *, size_t *, loff_t *);
2102 #endif
2103 
2104 void drop_slab(void);
2105 void drop_slab_node(int nid);
2106 
2107 #ifndef CONFIG_MMU
2108 #define randomize_va_space 0
2109 #else
2110 extern int randomize_va_space;
2111 #endif
2112 
2113 const char * arch_vma_name(struct vm_area_struct *vma);
2114 void print_vma_addr(char *prefix, unsigned long rip);
2115 
2116 void sparse_mem_maps_populate_node(struct page **map_map,
2117                                    unsigned long pnum_begin,
2118                                    unsigned long pnum_end,
2119                                    unsigned long map_count,
2120                                    int nodeid);
2121 
2122 struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
2123 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
2124 pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
2125 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
2126 pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
2127 void *vmemmap_alloc_block(unsigned long size, int node);
2128 void *vmemmap_alloc_block_buf(unsigned long size, int node);
2129 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
2130 int vmemmap_populate_basepages(unsigned long start, unsigned long end,
2131                                int node);
2132 int vmemmap_populate(unsigned long start, unsigned long end, int node);
2133 void vmemmap_populate_print_last(void);
2134 #ifdef CONFIG_MEMORY_HOTPLUG
2135 void vmemmap_free(unsigned long start, unsigned long end);
2136 #endif
2137 void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
2138                                   unsigned long size);
2139 
2140 enum mf_flags {
2141         MF_COUNT_INCREASED = 1 << 0,
2142         MF_ACTION_REQUIRED = 1 << 1,
2143         MF_MUST_KILL = 1 << 2,
2144         MF_SOFT_OFFLINE = 1 << 3,
2145 };
2146 extern int memory_failure(unsigned long pfn, int trapno, int flags);
2147 extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
2148 extern int unpoison_memory(unsigned long pfn);
2149 extern int sysctl_memory_failure_early_kill;
2150 extern int sysctl_memory_failure_recovery;
2151 extern void shake_page(struct page *p, int access);
2152 extern atomic_long_t num_poisoned_pages;
2153 extern int soft_offline_page(struct page *page, int flags);
2154 
2155 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
2156 extern void clear_huge_page(struct page *page,
2157                             unsigned long addr,
2158                             unsigned int pages_per_huge_page);
2159 extern void copy_user_huge_page(struct page *dst, struct page *src,
2160                                 unsigned long addr, struct vm_area_struct *vma,
2161                                 unsigned int pages_per_huge_page);
2162 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
2163 
2164 extern struct page_ext_operations debug_guardpage_ops;
2165 extern struct page_ext_operations page_poisoning_ops;
2166 
2167 #ifdef CONFIG_DEBUG_PAGEALLOC
2168 extern unsigned int _debug_guardpage_minorder;
2169 extern bool _debug_guardpage_enabled;
2170 
2171 static inline unsigned int debug_guardpage_minorder(void)
2172 {
2173         return _debug_guardpage_minorder;
2174 }
2175 
2176 static inline bool debug_guardpage_enabled(void)
2177 {
2178         return _debug_guardpage_enabled;
2179 }
2180 
2181 static inline bool page_is_guard(struct page *page)
2182 {
2183         struct page_ext *page_ext;
2184 
2185         if (!debug_guardpage_enabled())
2186                 return false;
2187 
2188         page_ext = lookup_page_ext(page);
2189         return test_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
2190 }
2191 #else
2192 static inline unsigned int debug_guardpage_minorder(void) { return 0; }
2193 static inline bool debug_guardpage_enabled(void) { return false; }
2194 static inline bool page_is_guard(struct page *page) { return false; }
2195 #endif /* CONFIG_DEBUG_PAGEALLOC */
2196 
2197 #if MAX_NUMNODES > 1
2198 void __init setup_nr_node_ids(void);
2199 #else
2200 static inline void setup_nr_node_ids(void) {}
2201 #endif
2202 
2203 #endif /* __KERNEL__ */
2204 #endif /* _LINUX_MM_H */
2205 

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