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TOMOYO Linux Cross Reference
Linux/include/linux/mm.h

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  1 #ifndef _LINUX_MM_H
  2 #define _LINUX_MM_H
  3 
  4 #include <linux/errno.h>
  5 
  6 #ifdef __KERNEL__
  7 
  8 #include <linux/gfp.h>
  9 #include <linux/list.h>
 10 #include <linux/mmzone.h>
 11 #include <linux/rbtree.h>
 12 #include <linux/prio_tree.h>
 13 #include <linux/debug_locks.h>
 14 #include <linux/mm_types.h>
 15 #include <linux/range.h>
 16 #include <linux/pfn.h>
 17 #include <linux/bit_spinlock.h>
 18 
 19 struct mempolicy;
 20 struct anon_vma;
 21 struct file_ra_state;
 22 struct user_struct;
 23 struct writeback_control;
 24 
 25 #ifndef CONFIG_DISCONTIGMEM          /* Don't use mapnrs, do it properly */
 26 extern unsigned long max_mapnr;
 27 #endif
 28 
 29 extern unsigned long num_physpages;
 30 extern unsigned long totalram_pages;
 31 extern void * high_memory;
 32 extern int page_cluster;
 33 
 34 #ifdef CONFIG_SYSCTL
 35 extern int sysctl_legacy_va_layout;
 36 #else
 37 #define sysctl_legacy_va_layout 0
 38 #endif
 39 
 40 #include <asm/page.h>
 41 #include <asm/pgtable.h>
 42 #include <asm/processor.h>
 43 
 44 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
 45 
 46 /* to align the pointer to the (next) page boundary */
 47 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
 48 
 49 /*
 50  * Linux kernel virtual memory manager primitives.
 51  * The idea being to have a "virtual" mm in the same way
 52  * we have a virtual fs - giving a cleaner interface to the
 53  * mm details, and allowing different kinds of memory mappings
 54  * (from shared memory to executable loading to arbitrary
 55  * mmap() functions).
 56  */
 57 
 58 extern struct kmem_cache *vm_area_cachep;
 59 
 60 #ifndef CONFIG_MMU
 61 extern struct rb_root nommu_region_tree;
 62 extern struct rw_semaphore nommu_region_sem;
 63 
 64 extern unsigned int kobjsize(const void *objp);
 65 #endif
 66 
 67 /*
 68  * vm_flags in vm_area_struct, see mm_types.h.
 69  */
 70 #define VM_READ         0x00000001      /* currently active flags */
 71 #define VM_WRITE        0x00000002
 72 #define VM_EXEC         0x00000004
 73 #define VM_SHARED       0x00000008
 74 
 75 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
 76 #define VM_MAYREAD      0x00000010      /* limits for mprotect() etc */
 77 #define VM_MAYWRITE     0x00000020
 78 #define VM_MAYEXEC      0x00000040
 79 #define VM_MAYSHARE     0x00000080
 80 
 81 #define VM_GROWSDOWN    0x00000100      /* general info on the segment */
 82 #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
 83 #define VM_GROWSUP      0x00000200
 84 #else
 85 #define VM_GROWSUP      0x00000000
 86 #define VM_NOHUGEPAGE   0x00000200      /* MADV_NOHUGEPAGE marked this vma */
 87 #endif
 88 #define VM_PFNMAP       0x00000400      /* Page-ranges managed without "struct page", just pure PFN */
 89 #define VM_DENYWRITE    0x00000800      /* ETXTBSY on write attempts.. */
 90 
 91 #define VM_EXECUTABLE   0x00001000
 92 #define VM_LOCKED       0x00002000
 93 #define VM_IO           0x00004000      /* Memory mapped I/O or similar */
 94 
 95                                         /* Used by sys_madvise() */
 96 #define VM_SEQ_READ     0x00008000      /* App will access data sequentially */
 97 #define VM_RAND_READ    0x00010000      /* App will not benefit from clustered reads */
 98 
 99 #define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
100 #define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
101 #define VM_RESERVED     0x00080000      /* Count as reserved_vm like IO */
102 #define VM_ACCOUNT      0x00100000      /* Is a VM accounted object */
103 #define VM_NORESERVE    0x00200000      /* should the VM suppress accounting */
104 #define VM_HUGETLB      0x00400000      /* Huge TLB Page VM */
105 #define VM_NONLINEAR    0x00800000      /* Is non-linear (remap_file_pages) */
106 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
107 #define VM_MAPPED_COPY  0x01000000      /* T if mapped copy of data (nommu mmap) */
108 #else
109 #define VM_HUGEPAGE     0x01000000      /* MADV_HUGEPAGE marked this vma */
110 #endif
111 #define VM_INSERTPAGE   0x02000000      /* The vma has had "vm_insert_page()" done on it */
112 #define VM_ALWAYSDUMP   0x04000000      /* Always include in core dumps */
113 
114 #define VM_CAN_NONLINEAR 0x08000000     /* Has ->fault & does nonlinear pages */
115 #define VM_MIXEDMAP     0x10000000      /* Can contain "struct page" and pure PFN pages */
116 #define VM_SAO          0x20000000      /* Strong Access Ordering (powerpc) */
117 #define VM_PFN_AT_MMAP  0x40000000      /* PFNMAP vma that is fully mapped at mmap time */
118 #define VM_MERGEABLE    0x80000000      /* KSM may merge identical pages */
119 
120 /* Bits set in the VMA until the stack is in its final location */
121 #define VM_STACK_INCOMPLETE_SETUP       (VM_RAND_READ | VM_SEQ_READ)
122 
123 #ifndef VM_STACK_DEFAULT_FLAGS          /* arch can override this */
124 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
125 #endif
126 
127 #ifdef CONFIG_STACK_GROWSUP
128 #define VM_STACK_FLAGS  (VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
129 #else
130 #define VM_STACK_FLAGS  (VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
131 #endif
132 
133 #define VM_READHINTMASK                 (VM_SEQ_READ | VM_RAND_READ)
134 #define VM_ClearReadHint(v)             (v)->vm_flags &= ~VM_READHINTMASK
135 #define VM_NormalReadHint(v)            (!((v)->vm_flags & VM_READHINTMASK))
136 #define VM_SequentialReadHint(v)        ((v)->vm_flags & VM_SEQ_READ)
137 #define VM_RandomReadHint(v)            ((v)->vm_flags & VM_RAND_READ)
138 
139 /*
140  * Special vmas that are non-mergable, non-mlock()able.
141  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
142  */
143 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
144 
145 /*
146  * mapping from the currently active vm_flags protection bits (the
147  * low four bits) to a page protection mask..
148  */
149 extern pgprot_t protection_map[16];
150 
151 #define FAULT_FLAG_WRITE        0x01    /* Fault was a write access */
152 #define FAULT_FLAG_NONLINEAR    0x02    /* Fault was via a nonlinear mapping */
153 #define FAULT_FLAG_MKWRITE      0x04    /* Fault was mkwrite of existing pte */
154 #define FAULT_FLAG_ALLOW_RETRY  0x08    /* Retry fault if blocking */
155 #define FAULT_FLAG_RETRY_NOWAIT 0x10    /* Don't drop mmap_sem and wait when retrying */
156 
157 /*
158  * This interface is used by x86 PAT code to identify a pfn mapping that is
159  * linear over entire vma. This is to optimize PAT code that deals with
160  * marking the physical region with a particular prot. This is not for generic
161  * mm use. Note also that this check will not work if the pfn mapping is
162  * linear for a vma starting at physical address 0. In which case PAT code
163  * falls back to slow path of reserving physical range page by page.
164  */
165 static inline int is_linear_pfn_mapping(struct vm_area_struct *vma)
166 {
167         return (vma->vm_flags & VM_PFN_AT_MMAP);
168 }
169 
170 static inline int is_pfn_mapping(struct vm_area_struct *vma)
171 {
172         return (vma->vm_flags & VM_PFNMAP);
173 }
174 
175 /*
176  * vm_fault is filled by the the pagefault handler and passed to the vma's
177  * ->fault function. The vma's ->fault is responsible for returning a bitmask
178  * of VM_FAULT_xxx flags that give details about how the fault was handled.
179  *
180  * pgoff should be used in favour of virtual_address, if possible. If pgoff
181  * is used, one may set VM_CAN_NONLINEAR in the vma->vm_flags to get nonlinear
182  * mapping support.
183  */
184 struct vm_fault {
185         unsigned int flags;             /* FAULT_FLAG_xxx flags */
186         pgoff_t pgoff;                  /* Logical page offset based on vma */
187         void __user *virtual_address;   /* Faulting virtual address */
188 
189         struct page *page;              /* ->fault handlers should return a
190                                          * page here, unless VM_FAULT_NOPAGE
191                                          * is set (which is also implied by
192                                          * VM_FAULT_ERROR).
193                                          */
194 };
195 
196 /*
197  * These are the virtual MM functions - opening of an area, closing and
198  * unmapping it (needed to keep files on disk up-to-date etc), pointer
199  * to the functions called when a no-page or a wp-page exception occurs. 
200  */
201 struct vm_operations_struct {
202         void (*open)(struct vm_area_struct * area);
203         void (*close)(struct vm_area_struct * area);
204         int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
205 
206         /* notification that a previously read-only page is about to become
207          * writable, if an error is returned it will cause a SIGBUS */
208         int (*page_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
209 
210         /* called by access_process_vm when get_user_pages() fails, typically
211          * for use by special VMAs that can switch between memory and hardware
212          */
213         int (*access)(struct vm_area_struct *vma, unsigned long addr,
214                       void *buf, int len, int write);
215 #ifdef CONFIG_NUMA
216         /*
217          * set_policy() op must add a reference to any non-NULL @new mempolicy
218          * to hold the policy upon return.  Caller should pass NULL @new to
219          * remove a policy and fall back to surrounding context--i.e. do not
220          * install a MPOL_DEFAULT policy, nor the task or system default
221          * mempolicy.
222          */
223         int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
224 
225         /*
226          * get_policy() op must add reference [mpol_get()] to any policy at
227          * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
228          * in mm/mempolicy.c will do this automatically.
229          * get_policy() must NOT add a ref if the policy at (vma,addr) is not
230          * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
231          * If no [shared/vma] mempolicy exists at the addr, get_policy() op
232          * must return NULL--i.e., do not "fallback" to task or system default
233          * policy.
234          */
235         struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
236                                         unsigned long addr);
237         int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
238                 const nodemask_t *to, unsigned long flags);
239 #endif
240 };
241 
242 struct mmu_gather;
243 struct inode;
244 
245 #define page_private(page)              ((page)->private)
246 #define set_page_private(page, v)       ((page)->private = (v))
247 
248 /*
249  * FIXME: take this include out, include page-flags.h in
250  * files which need it (119 of them)
251  */
252 #include <linux/page-flags.h>
253 #include <linux/huge_mm.h>
254 
255 /*
256  * Methods to modify the page usage count.
257  *
258  * What counts for a page usage:
259  * - cache mapping   (page->mapping)
260  * - private data    (page->private)
261  * - page mapped in a task's page tables, each mapping
262  *   is counted separately
263  *
264  * Also, many kernel routines increase the page count before a critical
265  * routine so they can be sure the page doesn't go away from under them.
266  */
267 
268 /*
269  * Drop a ref, return true if the refcount fell to zero (the page has no users)
270  */
271 static inline int put_page_testzero(struct page *page)
272 {
273         VM_BUG_ON(atomic_read(&page->_count) == 0);
274         return atomic_dec_and_test(&page->_count);
275 }
276 
277 /*
278  * Try to grab a ref unless the page has a refcount of zero, return false if
279  * that is the case.
280  */
281 static inline int get_page_unless_zero(struct page *page)
282 {
283         return atomic_inc_not_zero(&page->_count);
284 }
285 
286 extern int page_is_ram(unsigned long pfn);
287 
288 /* Support for virtually mapped pages */
289 struct page *vmalloc_to_page(const void *addr);
290 unsigned long vmalloc_to_pfn(const void *addr);
291 
292 /*
293  * Determine if an address is within the vmalloc range
294  *
295  * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
296  * is no special casing required.
297  */
298 static inline int is_vmalloc_addr(const void *x)
299 {
300 #ifdef CONFIG_MMU
301         unsigned long addr = (unsigned long)x;
302 
303         return addr >= VMALLOC_START && addr < VMALLOC_END;
304 #else
305         return 0;
306 #endif
307 }
308 #ifdef CONFIG_MMU
309 extern int is_vmalloc_or_module_addr(const void *x);
310 #else
311 static inline int is_vmalloc_or_module_addr(const void *x)
312 {
313         return 0;
314 }
315 #endif
316 
317 static inline void compound_lock(struct page *page)
318 {
319 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
320         bit_spin_lock(PG_compound_lock, &page->flags);
321 #endif
322 }
323 
324 static inline void compound_unlock(struct page *page)
325 {
326 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
327         bit_spin_unlock(PG_compound_lock, &page->flags);
328 #endif
329 }
330 
331 static inline unsigned long compound_lock_irqsave(struct page *page)
332 {
333         unsigned long uninitialized_var(flags);
334 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
335         local_irq_save(flags);
336         compound_lock(page);
337 #endif
338         return flags;
339 }
340 
341 static inline void compound_unlock_irqrestore(struct page *page,
342                                               unsigned long flags)
343 {
344 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
345         compound_unlock(page);
346         local_irq_restore(flags);
347 #endif
348 }
349 
350 static inline struct page *compound_head(struct page *page)
351 {
352         if (unlikely(PageTail(page)))
353                 return page->first_page;
354         return page;
355 }
356 
357 static inline int page_count(struct page *page)
358 {
359         return atomic_read(&compound_head(page)->_count);
360 }
361 
362 static inline void get_page(struct page *page)
363 {
364         /*
365          * Getting a normal page or the head of a compound page
366          * requires to already have an elevated page->_count. Only if
367          * we're getting a tail page, the elevated page->_count is
368          * required only in the head page, so for tail pages the
369          * bugcheck only verifies that the page->_count isn't
370          * negative.
371          */
372         VM_BUG_ON(atomic_read(&page->_count) < !PageTail(page));
373         atomic_inc(&page->_count);
374         /*
375          * Getting a tail page will elevate both the head and tail
376          * page->_count(s).
377          */
378         if (unlikely(PageTail(page))) {
379                 /*
380                  * This is safe only because
381                  * __split_huge_page_refcount can't run under
382                  * get_page().
383                  */
384                 VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
385                 atomic_inc(&page->first_page->_count);
386         }
387 }
388 
389 static inline struct page *virt_to_head_page(const void *x)
390 {
391         struct page *page = virt_to_page(x);
392         return compound_head(page);
393 }
394 
395 /*
396  * Setup the page count before being freed into the page allocator for
397  * the first time (boot or memory hotplug)
398  */
399 static inline void init_page_count(struct page *page)
400 {
401         atomic_set(&page->_count, 1);
402 }
403 
404 /*
405  * PageBuddy() indicate that the page is free and in the buddy system
406  * (see mm/page_alloc.c).
407  *
408  * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to
409  * -2 so that an underflow of the page_mapcount() won't be mistaken
410  * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very
411  * efficiently by most CPU architectures.
412  */
413 #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
414 
415 static inline int PageBuddy(struct page *page)
416 {
417         return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE;
418 }
419 
420 static inline void __SetPageBuddy(struct page *page)
421 {
422         VM_BUG_ON(atomic_read(&page->_mapcount) != -1);
423         atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
424 }
425 
426 static inline void __ClearPageBuddy(struct page *page)
427 {
428         VM_BUG_ON(!PageBuddy(page));
429         atomic_set(&page->_mapcount, -1);
430 }
431 
432 void put_page(struct page *page);
433 void put_pages_list(struct list_head *pages);
434 
435 void split_page(struct page *page, unsigned int order);
436 int split_free_page(struct page *page);
437 
438 /*
439  * Compound pages have a destructor function.  Provide a
440  * prototype for that function and accessor functions.
441  * These are _only_ valid on the head of a PG_compound page.
442  */
443 typedef void compound_page_dtor(struct page *);
444 
445 static inline void set_compound_page_dtor(struct page *page,
446                                                 compound_page_dtor *dtor)
447 {
448         page[1].lru.next = (void *)dtor;
449 }
450 
451 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
452 {
453         return (compound_page_dtor *)page[1].lru.next;
454 }
455 
456 static inline int compound_order(struct page *page)
457 {
458         if (!PageHead(page))
459                 return 0;
460         return (unsigned long)page[1].lru.prev;
461 }
462 
463 static inline int compound_trans_order(struct page *page)
464 {
465         int order;
466         unsigned long flags;
467 
468         if (!PageHead(page))
469                 return 0;
470 
471         flags = compound_lock_irqsave(page);
472         order = compound_order(page);
473         compound_unlock_irqrestore(page, flags);
474         return order;
475 }
476 
477 static inline void set_compound_order(struct page *page, unsigned long order)
478 {
479         page[1].lru.prev = (void *)order;
480 }
481 
482 #ifdef CONFIG_MMU
483 /*
484  * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
485  * servicing faults for write access.  In the normal case, do always want
486  * pte_mkwrite.  But get_user_pages can cause write faults for mappings
487  * that do not have writing enabled, when used by access_process_vm.
488  */
489 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
490 {
491         if (likely(vma->vm_flags & VM_WRITE))
492                 pte = pte_mkwrite(pte);
493         return pte;
494 }
495 #endif
496 
497 /*
498  * Multiple processes may "see" the same page. E.g. for untouched
499  * mappings of /dev/null, all processes see the same page full of
500  * zeroes, and text pages of executables and shared libraries have
501  * only one copy in memory, at most, normally.
502  *
503  * For the non-reserved pages, page_count(page) denotes a reference count.
504  *   page_count() == 0 means the page is free. page->lru is then used for
505  *   freelist management in the buddy allocator.
506  *   page_count() > 0  means the page has been allocated.
507  *
508  * Pages are allocated by the slab allocator in order to provide memory
509  * to kmalloc and kmem_cache_alloc. In this case, the management of the
510  * page, and the fields in 'struct page' are the responsibility of mm/slab.c
511  * unless a particular usage is carefully commented. (the responsibility of
512  * freeing the kmalloc memory is the caller's, of course).
513  *
514  * A page may be used by anyone else who does a __get_free_page().
515  * In this case, page_count still tracks the references, and should only
516  * be used through the normal accessor functions. The top bits of page->flags
517  * and page->virtual store page management information, but all other fields
518  * are unused and could be used privately, carefully. The management of this
519  * page is the responsibility of the one who allocated it, and those who have
520  * subsequently been given references to it.
521  *
522  * The other pages (we may call them "pagecache pages") are completely
523  * managed by the Linux memory manager: I/O, buffers, swapping etc.
524  * The following discussion applies only to them.
525  *
526  * A pagecache page contains an opaque `private' member, which belongs to the
527  * page's address_space. Usually, this is the address of a circular list of
528  * the page's disk buffers. PG_private must be set to tell the VM to call
529  * into the filesystem to release these pages.
530  *
531  * A page may belong to an inode's memory mapping. In this case, page->mapping
532  * is the pointer to the inode, and page->index is the file offset of the page,
533  * in units of PAGE_CACHE_SIZE.
534  *
535  * If pagecache pages are not associated with an inode, they are said to be
536  * anonymous pages. These may become associated with the swapcache, and in that
537  * case PG_swapcache is set, and page->private is an offset into the swapcache.
538  *
539  * In either case (swapcache or inode backed), the pagecache itself holds one
540  * reference to the page. Setting PG_private should also increment the
541  * refcount. The each user mapping also has a reference to the page.
542  *
543  * The pagecache pages are stored in a per-mapping radix tree, which is
544  * rooted at mapping->page_tree, and indexed by offset.
545  * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
546  * lists, we instead now tag pages as dirty/writeback in the radix tree.
547  *
548  * All pagecache pages may be subject to I/O:
549  * - inode pages may need to be read from disk,
550  * - inode pages which have been modified and are MAP_SHARED may need
551  *   to be written back to the inode on disk,
552  * - anonymous pages (including MAP_PRIVATE file mappings) which have been
553  *   modified may need to be swapped out to swap space and (later) to be read
554  *   back into memory.
555  */
556 
557 /*
558  * The zone field is never updated after free_area_init_core()
559  * sets it, so none of the operations on it need to be atomic.
560  */
561 
562 
563 /*
564  * page->flags layout:
565  *
566  * There are three possibilities for how page->flags get
567  * laid out.  The first is for the normal case, without
568  * sparsemem.  The second is for sparsemem when there is
569  * plenty of space for node and section.  The last is when
570  * we have run out of space and have to fall back to an
571  * alternate (slower) way of determining the node.
572  *
573  * No sparsemem or sparsemem vmemmap: |       NODE     | ZONE | ... | FLAGS |
574  * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS |
575  * classic sparse no space for node:  | SECTION |     ZONE    | ... | FLAGS |
576  */
577 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
578 #define SECTIONS_WIDTH          SECTIONS_SHIFT
579 #else
580 #define SECTIONS_WIDTH          0
581 #endif
582 
583 #define ZONES_WIDTH             ZONES_SHIFT
584 
585 #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
586 #define NODES_WIDTH             NODES_SHIFT
587 #else
588 #ifdef CONFIG_SPARSEMEM_VMEMMAP
589 #error "Vmemmap: No space for nodes field in page flags"
590 #endif
591 #define NODES_WIDTH             0
592 #endif
593 
594 /* Page flags: | [SECTION] | [NODE] | ZONE | ... | FLAGS | */
595 #define SECTIONS_PGOFF          ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
596 #define NODES_PGOFF             (SECTIONS_PGOFF - NODES_WIDTH)
597 #define ZONES_PGOFF             (NODES_PGOFF - ZONES_WIDTH)
598 
599 /*
600  * We are going to use the flags for the page to node mapping if its in
601  * there.  This includes the case where there is no node, so it is implicit.
602  */
603 #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
604 #define NODE_NOT_IN_PAGE_FLAGS
605 #endif
606 
607 #ifndef PFN_SECTION_SHIFT
608 #define PFN_SECTION_SHIFT 0
609 #endif
610 
611 /*
612  * Define the bit shifts to access each section.  For non-existent
613  * sections we define the shift as 0; that plus a 0 mask ensures
614  * the compiler will optimise away reference to them.
615  */
616 #define SECTIONS_PGSHIFT        (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
617 #define NODES_PGSHIFT           (NODES_PGOFF * (NODES_WIDTH != 0))
618 #define ZONES_PGSHIFT           (ZONES_PGOFF * (ZONES_WIDTH != 0))
619 
620 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
621 #ifdef NODE_NOT_IN_PAGE_FLAGS
622 #define ZONEID_SHIFT            (SECTIONS_SHIFT + ZONES_SHIFT)
623 #define ZONEID_PGOFF            ((SECTIONS_PGOFF < ZONES_PGOFF)? \
624                                                 SECTIONS_PGOFF : ZONES_PGOFF)
625 #else
626 #define ZONEID_SHIFT            (NODES_SHIFT + ZONES_SHIFT)
627 #define ZONEID_PGOFF            ((NODES_PGOFF < ZONES_PGOFF)? \
628                                                 NODES_PGOFF : ZONES_PGOFF)
629 #endif
630 
631 #define ZONEID_PGSHIFT          (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
632 
633 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
634 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
635 #endif
636 
637 #define ZONES_MASK              ((1UL << ZONES_WIDTH) - 1)
638 #define NODES_MASK              ((1UL << NODES_WIDTH) - 1)
639 #define SECTIONS_MASK           ((1UL << SECTIONS_WIDTH) - 1)
640 #define ZONEID_MASK             ((1UL << ZONEID_SHIFT) - 1)
641 
642 static inline enum zone_type page_zonenum(struct page *page)
643 {
644         return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
645 }
646 
647 /*
648  * The identification function is only used by the buddy allocator for
649  * determining if two pages could be buddies. We are not really
650  * identifying a zone since we could be using a the section number
651  * id if we have not node id available in page flags.
652  * We guarantee only that it will return the same value for two
653  * combinable pages in a zone.
654  */
655 static inline int page_zone_id(struct page *page)
656 {
657         return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
658 }
659 
660 static inline int zone_to_nid(struct zone *zone)
661 {
662 #ifdef CONFIG_NUMA
663         return zone->node;
664 #else
665         return 0;
666 #endif
667 }
668 
669 #ifdef NODE_NOT_IN_PAGE_FLAGS
670 extern int page_to_nid(struct page *page);
671 #else
672 static inline int page_to_nid(struct page *page)
673 {
674         return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
675 }
676 #endif
677 
678 static inline struct zone *page_zone(struct page *page)
679 {
680         return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
681 }
682 
683 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
684 static inline unsigned long page_to_section(struct page *page)
685 {
686         return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
687 }
688 #endif
689 
690 static inline void set_page_zone(struct page *page, enum zone_type zone)
691 {
692         page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
693         page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
694 }
695 
696 static inline void set_page_node(struct page *page, unsigned long node)
697 {
698         page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
699         page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
700 }
701 
702 static inline void set_page_section(struct page *page, unsigned long section)
703 {
704         page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
705         page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
706 }
707 
708 static inline void set_page_links(struct page *page, enum zone_type zone,
709         unsigned long node, unsigned long pfn)
710 {
711         set_page_zone(page, zone);
712         set_page_node(page, node);
713         set_page_section(page, pfn_to_section_nr(pfn));
714 }
715 
716 /*
717  * Some inline functions in vmstat.h depend on page_zone()
718  */
719 #include <linux/vmstat.h>
720 
721 static __always_inline void *lowmem_page_address(struct page *page)
722 {
723         return __va(PFN_PHYS(page_to_pfn(page)));
724 }
725 
726 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
727 #define HASHED_PAGE_VIRTUAL
728 #endif
729 
730 #if defined(WANT_PAGE_VIRTUAL)
731 #define page_address(page) ((page)->virtual)
732 #define set_page_address(page, address)                 \
733         do {                                            \
734                 (page)->virtual = (address);            \
735         } while(0)
736 #define page_address_init()  do { } while(0)
737 #endif
738 
739 #if defined(HASHED_PAGE_VIRTUAL)
740 void *page_address(struct page *page);
741 void set_page_address(struct page *page, void *virtual);
742 void page_address_init(void);
743 #endif
744 
745 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
746 #define page_address(page) lowmem_page_address(page)
747 #define set_page_address(page, address)  do { } while(0)
748 #define page_address_init()  do { } while(0)
749 #endif
750 
751 /*
752  * On an anonymous page mapped into a user virtual memory area,
753  * page->mapping points to its anon_vma, not to a struct address_space;
754  * with the PAGE_MAPPING_ANON bit set to distinguish it.  See rmap.h.
755  *
756  * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
757  * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
758  * and then page->mapping points, not to an anon_vma, but to a private
759  * structure which KSM associates with that merged page.  See ksm.h.
760  *
761  * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
762  *
763  * Please note that, confusingly, "page_mapping" refers to the inode
764  * address_space which maps the page from disk; whereas "page_mapped"
765  * refers to user virtual address space into which the page is mapped.
766  */
767 #define PAGE_MAPPING_ANON       1
768 #define PAGE_MAPPING_KSM        2
769 #define PAGE_MAPPING_FLAGS      (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
770 
771 extern struct address_space swapper_space;
772 static inline struct address_space *page_mapping(struct page *page)
773 {
774         struct address_space *mapping = page->mapping;
775 
776         VM_BUG_ON(PageSlab(page));
777         if (unlikely(PageSwapCache(page)))
778                 mapping = &swapper_space;
779         else if ((unsigned long)mapping & PAGE_MAPPING_ANON)
780                 mapping = NULL;
781         return mapping;
782 }
783 
784 /* Neutral page->mapping pointer to address_space or anon_vma or other */
785 static inline void *page_rmapping(struct page *page)
786 {
787         return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS);
788 }
789 
790 static inline int PageAnon(struct page *page)
791 {
792         return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
793 }
794 
795 /*
796  * Return the pagecache index of the passed page.  Regular pagecache pages
797  * use ->index whereas swapcache pages use ->private
798  */
799 static inline pgoff_t page_index(struct page *page)
800 {
801         if (unlikely(PageSwapCache(page)))
802                 return page_private(page);
803         return page->index;
804 }
805 
806 /*
807  * The atomic page->_mapcount, like _count, starts from -1:
808  * so that transitions both from it and to it can be tracked,
809  * using atomic_inc_and_test and atomic_add_negative(-1).
810  */
811 static inline void reset_page_mapcount(struct page *page)
812 {
813         atomic_set(&(page)->_mapcount, -1);
814 }
815 
816 static inline int page_mapcount(struct page *page)
817 {
818         return atomic_read(&(page)->_mapcount) + 1;
819 }
820 
821 /*
822  * Return true if this page is mapped into pagetables.
823  */
824 static inline int page_mapped(struct page *page)
825 {
826         return atomic_read(&(page)->_mapcount) >= 0;
827 }
828 
829 /*
830  * Different kinds of faults, as returned by handle_mm_fault().
831  * Used to decide whether a process gets delivered SIGBUS or
832  * just gets major/minor fault counters bumped up.
833  */
834 
835 #define VM_FAULT_MINOR  0 /* For backwards compat. Remove me quickly. */
836 
837 #define VM_FAULT_OOM    0x0001
838 #define VM_FAULT_SIGBUS 0x0002
839 #define VM_FAULT_MAJOR  0x0004
840 #define VM_FAULT_WRITE  0x0008  /* Special case for get_user_pages */
841 #define VM_FAULT_HWPOISON 0x0010        /* Hit poisoned small page */
842 #define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
843 
844 #define VM_FAULT_NOPAGE 0x0100  /* ->fault installed the pte, not return page */
845 #define VM_FAULT_LOCKED 0x0200  /* ->fault locked the returned page */
846 #define VM_FAULT_RETRY  0x0400  /* ->fault blocked, must retry */
847 
848 #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */
849 
850 #define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON | \
851                          VM_FAULT_HWPOISON_LARGE)
852 
853 /* Encode hstate index for a hwpoisoned large page */
854 #define VM_FAULT_SET_HINDEX(x) ((x) << 12)
855 #define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
856 
857 /*
858  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
859  */
860 extern void pagefault_out_of_memory(void);
861 
862 #define offset_in_page(p)       ((unsigned long)(p) & ~PAGE_MASK)
863 
864 /*
865  * Flags passed to show_mem() and __show_free_areas() to suppress output in
866  * various contexts.
867  */
868 #define SHOW_MEM_FILTER_NODES   (0x0001u)       /* filter disallowed nodes */
869 
870 extern void show_free_areas(void);
871 extern void __show_free_areas(unsigned int flags);
872 
873 int shmem_lock(struct file *file, int lock, struct user_struct *user);
874 struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags);
875 int shmem_zero_setup(struct vm_area_struct *);
876 
877 #ifndef CONFIG_MMU
878 extern unsigned long shmem_get_unmapped_area(struct file *file,
879                                              unsigned long addr,
880                                              unsigned long len,
881                                              unsigned long pgoff,
882                                              unsigned long flags);
883 #endif
884 
885 extern int can_do_mlock(void);
886 extern int user_shm_lock(size_t, struct user_struct *);
887 extern void user_shm_unlock(size_t, struct user_struct *);
888 
889 /*
890  * Parameter block passed down to zap_pte_range in exceptional cases.
891  */
892 struct zap_details {
893         struct vm_area_struct *nonlinear_vma;   /* Check page->index if set */
894         struct address_space *check_mapping;    /* Check page->mapping if set */
895         pgoff_t first_index;                    /* Lowest page->index to unmap */
896         pgoff_t last_index;                     /* Highest page->index to unmap */
897         spinlock_t *i_mmap_lock;                /* For unmap_mapping_range: */
898         unsigned long truncate_count;           /* Compare vm_truncate_count */
899 };
900 
901 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
902                 pte_t pte);
903 
904 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
905                 unsigned long size);
906 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
907                 unsigned long size, struct zap_details *);
908 unsigned long unmap_vmas(struct mmu_gather **tlb,
909                 struct vm_area_struct *start_vma, unsigned long start_addr,
910                 unsigned long end_addr, unsigned long *nr_accounted,
911                 struct zap_details *);
912 
913 /**
914  * mm_walk - callbacks for walk_page_range
915  * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
916  * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
917  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
918  *             this handler is required to be able to handle
919  *             pmd_trans_huge() pmds.  They may simply choose to
920  *             split_huge_page() instead of handling it explicitly.
921  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
922  * @pte_hole: if set, called for each hole at all levels
923  * @hugetlb_entry: if set, called for each hugetlb entry
924  *
925  * (see walk_page_range for more details)
926  */
927 struct mm_walk {
928         int (*pgd_entry)(pgd_t *, unsigned long, unsigned long, struct mm_walk *);
929         int (*pud_entry)(pud_t *, unsigned long, unsigned long, struct mm_walk *);
930         int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, struct mm_walk *);
931         int (*pte_entry)(pte_t *, unsigned long, unsigned long, struct mm_walk *);
932         int (*pte_hole)(unsigned long, unsigned long, struct mm_walk *);
933         int (*hugetlb_entry)(pte_t *, unsigned long,
934                              unsigned long, unsigned long, struct mm_walk *);
935         struct mm_struct *mm;
936         void *private;
937 };
938 
939 int walk_page_range(unsigned long addr, unsigned long end,
940                 struct mm_walk *walk);
941 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
942                 unsigned long end, unsigned long floor, unsigned long ceiling);
943 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
944                         struct vm_area_struct *vma);
945 void unmap_mapping_range(struct address_space *mapping,
946                 loff_t const holebegin, loff_t const holelen, int even_cows);
947 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
948         unsigned long *pfn);
949 int follow_phys(struct vm_area_struct *vma, unsigned long address,
950                 unsigned int flags, unsigned long *prot, resource_size_t *phys);
951 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
952                         void *buf, int len, int write);
953 
954 static inline void unmap_shared_mapping_range(struct address_space *mapping,
955                 loff_t const holebegin, loff_t const holelen)
956 {
957         unmap_mapping_range(mapping, holebegin, holelen, 0);
958 }
959 
960 extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new);
961 extern void truncate_setsize(struct inode *inode, loff_t newsize);
962 extern int vmtruncate(struct inode *inode, loff_t offset);
963 extern int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end);
964 
965 int truncate_inode_page(struct address_space *mapping, struct page *page);
966 int generic_error_remove_page(struct address_space *mapping, struct page *page);
967 
968 int invalidate_inode_page(struct page *page);
969 
970 #ifdef CONFIG_MMU
971 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
972                         unsigned long address, unsigned int flags);
973 #else
974 static inline int handle_mm_fault(struct mm_struct *mm,
975                         struct vm_area_struct *vma, unsigned long address,
976                         unsigned int flags)
977 {
978         /* should never happen if there's no MMU */
979         BUG();
980         return VM_FAULT_SIGBUS;
981 }
982 #endif
983 
984 extern int make_pages_present(unsigned long addr, unsigned long end);
985 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
986 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
987                 void *buf, int len, int write);
988 
989 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
990                      unsigned long start, int len, unsigned int foll_flags,
991                      struct page **pages, struct vm_area_struct **vmas,
992                      int *nonblocking);
993 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
994                         unsigned long start, int nr_pages, int write, int force,
995                         struct page **pages, struct vm_area_struct **vmas);
996 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
997                         struct page **pages);
998 struct page *get_dump_page(unsigned long addr);
999 
1000 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
1001 extern void do_invalidatepage(struct page *page, unsigned long offset);
1002 
1003 int __set_page_dirty_nobuffers(struct page *page);
1004 int __set_page_dirty_no_writeback(struct page *page);
1005 int redirty_page_for_writepage(struct writeback_control *wbc,
1006                                 struct page *page);
1007 void account_page_dirtied(struct page *page, struct address_space *mapping);
1008 void account_page_writeback(struct page *page);
1009 int set_page_dirty(struct page *page);
1010 int set_page_dirty_lock(struct page *page);
1011 int clear_page_dirty_for_io(struct page *page);
1012 
1013 /* Is the vma a continuation of the stack vma above it? */
1014 static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
1015 {
1016         return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
1017 }
1018 
1019 static inline int stack_guard_page_start(struct vm_area_struct *vma,
1020                                              unsigned long addr)
1021 {
1022         return (vma->vm_flags & VM_GROWSDOWN) &&
1023                 (vma->vm_start == addr) &&
1024                 !vma_growsdown(vma->vm_prev, addr);
1025 }
1026 
1027 /* Is the vma a continuation of the stack vma below it? */
1028 static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
1029 {
1030         return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
1031 }
1032 
1033 static inline int stack_guard_page_end(struct vm_area_struct *vma,
1034                                            unsigned long addr)
1035 {
1036         return (vma->vm_flags & VM_GROWSUP) &&
1037                 (vma->vm_end == addr) &&
1038                 !vma_growsup(vma->vm_next, addr);
1039 }
1040 
1041 extern unsigned long move_page_tables(struct vm_area_struct *vma,
1042                 unsigned long old_addr, struct vm_area_struct *new_vma,
1043                 unsigned long new_addr, unsigned long len);
1044 extern unsigned long do_mremap(unsigned long addr,
1045                                unsigned long old_len, unsigned long new_len,
1046                                unsigned long flags, unsigned long new_addr);
1047 extern int mprotect_fixup(struct vm_area_struct *vma,
1048                           struct vm_area_struct **pprev, unsigned long start,
1049                           unsigned long end, unsigned long newflags);
1050 
1051 /*
1052  * doesn't attempt to fault and will return short.
1053  */
1054 int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
1055                           struct page **pages);
1056 /*
1057  * per-process(per-mm_struct) statistics.
1058  */
1059 #if defined(SPLIT_RSS_COUNTING)
1060 /*
1061  * The mm counters are not protected by its page_table_lock,
1062  * so must be incremented atomically.
1063  */
1064 static inline void set_mm_counter(struct mm_struct *mm, int member, long value)
1065 {
1066         atomic_long_set(&mm->rss_stat.count[member], value);
1067 }
1068 
1069 unsigned long get_mm_counter(struct mm_struct *mm, int member);
1070 
1071 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
1072 {
1073         atomic_long_add(value, &mm->rss_stat.count[member]);
1074 }
1075 
1076 static inline void inc_mm_counter(struct mm_struct *mm, int member)
1077 {
1078         atomic_long_inc(&mm->rss_stat.count[member]);
1079 }
1080 
1081 static inline void dec_mm_counter(struct mm_struct *mm, int member)
1082 {
1083         atomic_long_dec(&mm->rss_stat.count[member]);
1084 }
1085 
1086 #else  /* !USE_SPLIT_PTLOCKS */
1087 /*
1088  * The mm counters are protected by its page_table_lock,
1089  * so can be incremented directly.
1090  */
1091 static inline void set_mm_counter(struct mm_struct *mm, int member, long value)
1092 {
1093         mm->rss_stat.count[member] = value;
1094 }
1095 
1096 static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
1097 {
1098         return mm->rss_stat.count[member];
1099 }
1100 
1101 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
1102 {
1103         mm->rss_stat.count[member] += value;
1104 }
1105 
1106 static inline void inc_mm_counter(struct mm_struct *mm, int member)
1107 {
1108         mm->rss_stat.count[member]++;
1109 }
1110 
1111 static inline void dec_mm_counter(struct mm_struct *mm, int member)
1112 {
1113         mm->rss_stat.count[member]--;
1114 }
1115 
1116 #endif /* !USE_SPLIT_PTLOCKS */
1117 
1118 static inline unsigned long get_mm_rss(struct mm_struct *mm)
1119 {
1120         return get_mm_counter(mm, MM_FILEPAGES) +
1121                 get_mm_counter(mm, MM_ANONPAGES);
1122 }
1123 
1124 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
1125 {
1126         return max(mm->hiwater_rss, get_mm_rss(mm));
1127 }
1128 
1129 static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
1130 {
1131         return max(mm->hiwater_vm, mm->total_vm);
1132 }
1133 
1134 static inline void update_hiwater_rss(struct mm_struct *mm)
1135 {
1136         unsigned long _rss = get_mm_rss(mm);
1137 
1138         if ((mm)->hiwater_rss < _rss)
1139                 (mm)->hiwater_rss = _rss;
1140 }
1141 
1142 static inline void update_hiwater_vm(struct mm_struct *mm)
1143 {
1144         if (mm->hiwater_vm < mm->total_vm)
1145                 mm->hiwater_vm = mm->total_vm;
1146 }
1147 
1148 static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
1149                                          struct mm_struct *mm)
1150 {
1151         unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
1152 
1153         if (*maxrss < hiwater_rss)
1154                 *maxrss = hiwater_rss;
1155 }
1156 
1157 #if defined(SPLIT_RSS_COUNTING)
1158 void sync_mm_rss(struct task_struct *task, struct mm_struct *mm);
1159 #else
1160 static inline void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
1161 {
1162 }
1163 #endif
1164 
1165 /*
1166  * A callback you can register to apply pressure to ageable caches.
1167  *
1168  * 'shrink' is passed a count 'nr_to_scan' and a 'gfpmask'.  It should
1169  * look through the least-recently-used 'nr_to_scan' entries and
1170  * attempt to free them up.  It should return the number of objects
1171  * which remain in the cache.  If it returns -1, it means it cannot do
1172  * any scanning at this time (eg. there is a risk of deadlock).
1173  *
1174  * The 'gfpmask' refers to the allocation we are currently trying to
1175  * fulfil.
1176  *
1177  * Note that 'shrink' will be passed nr_to_scan == 0 when the VM is
1178  * querying the cache size, so a fastpath for that case is appropriate.
1179  */
1180 struct shrinker {
1181         int (*shrink)(struct shrinker *, int nr_to_scan, gfp_t gfp_mask);
1182         int seeks;      /* seeks to recreate an obj */
1183 
1184         /* These are for internal use */
1185         struct list_head list;
1186         long nr;        /* objs pending delete */
1187 };
1188 #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
1189 extern void register_shrinker(struct shrinker *);
1190 extern void unregister_shrinker(struct shrinker *);
1191 
1192 int vma_wants_writenotify(struct vm_area_struct *vma);
1193 
1194 extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1195                                spinlock_t **ptl);
1196 static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1197                                     spinlock_t **ptl)
1198 {
1199         pte_t *ptep;
1200         __cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
1201         return ptep;
1202 }
1203 
1204 #ifdef __PAGETABLE_PUD_FOLDED
1205 static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
1206                                                 unsigned long address)
1207 {
1208         return 0;
1209 }
1210 #else
1211 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
1212 #endif
1213 
1214 #ifdef __PAGETABLE_PMD_FOLDED
1215 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
1216                                                 unsigned long address)
1217 {
1218         return 0;
1219 }
1220 #else
1221 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
1222 #endif
1223 
1224 int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
1225                 pmd_t *pmd, unsigned long address);
1226 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
1227 
1228 /*
1229  * The following ifdef needed to get the 4level-fixup.h header to work.
1230  * Remove it when 4level-fixup.h has been removed.
1231  */
1232 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
1233 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
1234 {
1235         return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
1236                 NULL: pud_offset(pgd, address);
1237 }
1238 
1239 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
1240 {
1241         return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
1242                 NULL: pmd_offset(pud, address);
1243 }
1244 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
1245 
1246 #if USE_SPLIT_PTLOCKS
1247 /*
1248  * We tuck a spinlock to guard each pagetable page into its struct page,
1249  * at page->private, with BUILD_BUG_ON to make sure that this will not
1250  * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
1251  * When freeing, reset page->mapping so free_pages_check won't complain.
1252  */
1253 #define __pte_lockptr(page)     &((page)->ptl)
1254 #define pte_lock_init(_page)    do {                                    \
1255         spin_lock_init(__pte_lockptr(_page));                           \
1256 } while (0)
1257 #define pte_lock_deinit(page)   ((page)->mapping = NULL)
1258 #define pte_lockptr(mm, pmd)    ({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
1259 #else   /* !USE_SPLIT_PTLOCKS */
1260 /*
1261  * We use mm->page_table_lock to guard all pagetable pages of the mm.
1262  */
1263 #define pte_lock_init(page)     do {} while (0)
1264 #define pte_lock_deinit(page)   do {} while (0)
1265 #define pte_lockptr(mm, pmd)    ({(void)(pmd); &(mm)->page_table_lock;})
1266 #endif /* USE_SPLIT_PTLOCKS */
1267 
1268 static inline void pgtable_page_ctor(struct page *page)
1269 {
1270         pte_lock_init(page);
1271         inc_zone_page_state(page, NR_PAGETABLE);
1272 }
1273 
1274 static inline void pgtable_page_dtor(struct page *page)
1275 {
1276         pte_lock_deinit(page);
1277         dec_zone_page_state(page, NR_PAGETABLE);
1278 }
1279 
1280 #define pte_offset_map_lock(mm, pmd, address, ptlp)     \
1281 ({                                                      \
1282         spinlock_t *__ptl = pte_lockptr(mm, pmd);       \
1283         pte_t *__pte = pte_offset_map(pmd, address);    \
1284         *(ptlp) = __ptl;                                \
1285         spin_lock(__ptl);                               \
1286         __pte;                                          \
1287 })
1288 
1289 #define pte_unmap_unlock(pte, ptl)      do {            \
1290         spin_unlock(ptl);                               \
1291         pte_unmap(pte);                                 \
1292 } while (0)
1293 
1294 #define pte_alloc_map(mm, vma, pmd, address)                            \
1295         ((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, vma,    \
1296                                                         pmd, address))? \
1297          NULL: pte_offset_map(pmd, address))
1298 
1299 #define pte_alloc_map_lock(mm, pmd, address, ptlp)      \
1300         ((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, NULL,   \
1301                                                         pmd, address))? \
1302                 NULL: pte_offset_map_lock(mm, pmd, address, ptlp))
1303 
1304 #define pte_alloc_kernel(pmd, address)                  \
1305         ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
1306                 NULL: pte_offset_kernel(pmd, address))
1307 
1308 extern void free_area_init(unsigned long * zones_size);
1309 extern void free_area_init_node(int nid, unsigned long * zones_size,
1310                 unsigned long zone_start_pfn, unsigned long *zholes_size);
1311 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
1312 /*
1313  * With CONFIG_ARCH_POPULATES_NODE_MAP set, an architecture may initialise its
1314  * zones, allocate the backing mem_map and account for memory holes in a more
1315  * architecture independent manner. This is a substitute for creating the
1316  * zone_sizes[] and zholes_size[] arrays and passing them to
1317  * free_area_init_node()
1318  *
1319  * An architecture is expected to register range of page frames backed by
1320  * physical memory with add_active_range() before calling
1321  * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
1322  * usage, an architecture is expected to do something like
1323  *
1324  * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
1325  *                                                       max_highmem_pfn};
1326  * for_each_valid_physical_page_range()
1327  *      add_active_range(node_id, start_pfn, end_pfn)
1328  * free_area_init_nodes(max_zone_pfns);
1329  *
1330  * If the architecture guarantees that there are no holes in the ranges
1331  * registered with add_active_range(), free_bootmem_active_regions()
1332  * will call free_bootmem_node() for each registered physical page range.
1333  * Similarly sparse_memory_present_with_active_regions() calls
1334  * memory_present() for each range when SPARSEMEM is enabled.
1335  *
1336  * See mm/page_alloc.c for more information on each function exposed by
1337  * CONFIG_ARCH_POPULATES_NODE_MAP
1338  */
1339 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
1340 extern void add_active_range(unsigned int nid, unsigned long start_pfn,
1341                                         unsigned long end_pfn);
1342 extern void remove_active_range(unsigned int nid, unsigned long start_pfn,
1343                                         unsigned long end_pfn);
1344 extern void remove_all_active_ranges(void);
1345 void sort_node_map(void);
1346 unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
1347                                                 unsigned long end_pfn);
1348 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
1349                                                 unsigned long end_pfn);
1350 extern void get_pfn_range_for_nid(unsigned int nid,
1351                         unsigned long *start_pfn, unsigned long *end_pfn);
1352 extern unsigned long find_min_pfn_with_active_regions(void);
1353 extern void free_bootmem_with_active_regions(int nid,
1354                                                 unsigned long max_low_pfn);
1355 int add_from_early_node_map(struct range *range, int az,
1356                                    int nr_range, int nid);
1357 u64 __init find_memory_core_early(int nid, u64 size, u64 align,
1358                                         u64 goal, u64 limit);
1359 typedef int (*work_fn_t)(unsigned long, unsigned long, void *);
1360 extern void work_with_active_regions(int nid, work_fn_t work_fn, void *data);
1361 extern void sparse_memory_present_with_active_regions(int nid);
1362 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
1363 
1364 #if !defined(CONFIG_ARCH_POPULATES_NODE_MAP) && \
1365     !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
1366 static inline int __early_pfn_to_nid(unsigned long pfn)
1367 {
1368         return 0;
1369 }
1370 #else
1371 /* please see mm/page_alloc.c */
1372 extern int __meminit early_pfn_to_nid(unsigned long pfn);
1373 #ifdef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
1374 /* there is a per-arch backend function. */
1375 extern int __meminit __early_pfn_to_nid(unsigned long pfn);
1376 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
1377 #endif
1378 
1379 extern void set_dma_reserve(unsigned long new_dma_reserve);
1380 extern void memmap_init_zone(unsigned long, int, unsigned long,
1381                                 unsigned long, enum memmap_context);
1382 extern void setup_per_zone_wmarks(void);
1383 extern void calculate_zone_inactive_ratio(struct zone *zone);
1384 extern void mem_init(void);
1385 extern void __init mmap_init(void);
1386 extern void show_mem(unsigned int flags);
1387 extern void si_meminfo(struct sysinfo * val);
1388 extern void si_meminfo_node(struct sysinfo *val, int nid);
1389 extern int after_bootmem;
1390 
1391 extern void setup_per_cpu_pageset(void);
1392 
1393 extern void zone_pcp_update(struct zone *zone);
1394 
1395 /* nommu.c */
1396 extern atomic_long_t mmap_pages_allocated;
1397 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
1398 
1399 /* prio_tree.c */
1400 void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
1401 void vma_prio_tree_insert(struct vm_area_struct *, struct prio_tree_root *);
1402 void vma_prio_tree_remove(struct vm_area_struct *, struct prio_tree_root *);
1403 struct vm_area_struct *vma_prio_tree_next(struct vm_area_struct *vma,
1404         struct prio_tree_iter *iter);
1405 
1406 #define vma_prio_tree_foreach(vma, iter, root, begin, end)      \
1407         for (prio_tree_iter_init(iter, root, begin, end), vma = NULL;   \
1408                 (vma = vma_prio_tree_next(vma, iter)); )
1409 
1410 static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
1411                                         struct list_head *list)
1412 {
1413         vma->shared.vm_set.parent = NULL;
1414         list_add_tail(&vma->shared.vm_set.list, list);
1415 }
1416 
1417 /* mmap.c */
1418 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
1419 extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
1420         unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
1421 extern struct vm_area_struct *vma_merge(struct mm_struct *,
1422         struct vm_area_struct *prev, unsigned long addr, unsigned long end,
1423         unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
1424         struct mempolicy *);
1425 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
1426 extern int split_vma(struct mm_struct *,
1427         struct vm_area_struct *, unsigned long addr, int new_below);
1428 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
1429 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
1430         struct rb_node **, struct rb_node *);
1431 extern void unlink_file_vma(struct vm_area_struct *);
1432 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
1433         unsigned long addr, unsigned long len, pgoff_t pgoff);
1434 extern void exit_mmap(struct mm_struct *);
1435 
1436 extern int mm_take_all_locks(struct mm_struct *mm);
1437 extern void mm_drop_all_locks(struct mm_struct *mm);
1438 
1439 #ifdef CONFIG_PROC_FS
1440 /* From fs/proc/base.c. callers must _not_ hold the mm's exe_file_lock */
1441 extern void added_exe_file_vma(struct mm_struct *mm);
1442 extern void removed_exe_file_vma(struct mm_struct *mm);
1443 #else
1444 static inline void added_exe_file_vma(struct mm_struct *mm)
1445 {}
1446 
1447 static inline void removed_exe_file_vma(struct mm_struct *mm)
1448 {}
1449 #endif /* CONFIG_PROC_FS */
1450 
1451 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
1452 extern int install_special_mapping(struct mm_struct *mm,
1453                                    unsigned long addr, unsigned long len,
1454                                    unsigned long flags, struct page **pages);
1455 
1456 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1457 
1458 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
1459         unsigned long len, unsigned long prot,
1460         unsigned long flag, unsigned long pgoff);
1461 extern unsigned long mmap_region(struct file *file, unsigned long addr,
1462         unsigned long len, unsigned long flags,
1463         unsigned int vm_flags, unsigned long pgoff);
1464 
1465 static inline unsigned long do_mmap(struct file *file, unsigned long addr,
1466         unsigned long len, unsigned long prot,
1467         unsigned long flag, unsigned long offset)
1468 {
1469         unsigned long ret = -EINVAL;
1470         if ((offset + PAGE_ALIGN(len)) < offset)
1471                 goto out;
1472         if (!(offset & ~PAGE_MASK))
1473                 ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
1474 out:
1475         return ret;
1476 }
1477 
1478 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
1479 
1480 extern unsigned long do_brk(unsigned long, unsigned long);
1481 
1482 /* filemap.c */
1483 extern unsigned long page_unuse(struct page *);
1484 extern void truncate_inode_pages(struct address_space *, loff_t);
1485 extern void truncate_inode_pages_range(struct address_space *,
1486                                        loff_t lstart, loff_t lend);
1487 
1488 /* generic vm_area_ops exported for stackable file systems */
1489 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
1490 
1491 /* mm/page-writeback.c */
1492 int write_one_page(struct page *page, int wait);
1493 void task_dirty_inc(struct task_struct *tsk);
1494 
1495 /* readahead.c */
1496 #define VM_MAX_READAHEAD        128     /* kbytes */
1497 #define VM_MIN_READAHEAD        16      /* kbytes (includes current page) */
1498 
1499 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
1500                         pgoff_t offset, unsigned long nr_to_read);
1501 
1502 void page_cache_sync_readahead(struct address_space *mapping,
1503                                struct file_ra_state *ra,
1504                                struct file *filp,
1505                                pgoff_t offset,
1506                                unsigned long size);
1507 
1508 void page_cache_async_readahead(struct address_space *mapping,
1509                                 struct file_ra_state *ra,
1510                                 struct file *filp,
1511                                 struct page *pg,
1512                                 pgoff_t offset,
1513                                 unsigned long size);
1514 
1515 unsigned long max_sane_readahead(unsigned long nr);
1516 unsigned long ra_submit(struct file_ra_state *ra,
1517                         struct address_space *mapping,
1518                         struct file *filp);
1519 
1520 /* Do stack extension */
1521 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
1522 #if VM_GROWSUP
1523 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
1524 #else
1525   #define expand_upwards(vma, address) do { } while (0)
1526 #endif
1527 extern int expand_stack_downwards(struct vm_area_struct *vma,
1528                                   unsigned long address);
1529 
1530 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
1531 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
1532 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
1533                                              struct vm_area_struct **pprev);
1534 
1535 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
1536    NULL if none.  Assume start_addr < end_addr. */
1537 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
1538 {
1539         struct vm_area_struct * vma = find_vma(mm,start_addr);
1540 
1541         if (vma && end_addr <= vma->vm_start)
1542                 vma = NULL;
1543         return vma;
1544 }
1545 
1546 static inline unsigned long vma_pages(struct vm_area_struct *vma)
1547 {
1548         return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
1549 }
1550 
1551 #ifdef CONFIG_MMU
1552 pgprot_t vm_get_page_prot(unsigned long vm_flags);
1553 #else
1554 static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
1555 {
1556         return __pgprot(0);
1557 }
1558 #endif
1559 
1560 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
1561 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
1562                         unsigned long pfn, unsigned long size, pgprot_t);
1563 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
1564 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1565                         unsigned long pfn);
1566 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1567                         unsigned long pfn);
1568 
1569 struct page *follow_page(struct vm_area_struct *, unsigned long address,
1570                         unsigned int foll_flags);
1571 #define FOLL_WRITE      0x01    /* check pte is writable */
1572 #define FOLL_TOUCH      0x02    /* mark page accessed */
1573 #define FOLL_GET        0x04    /* do get_page on page */
1574 #define FOLL_DUMP       0x08    /* give error on hole if it would be zero */
1575 #define FOLL_FORCE      0x10    /* get_user_pages read/write w/o permission */
1576 #define FOLL_NOWAIT     0x20    /* if a disk transfer is needed, start the IO
1577                                  * and return without waiting upon it */
1578 #define FOLL_MLOCK      0x40    /* mark page as mlocked */
1579 #define FOLL_SPLIT      0x80    /* don't return transhuge pages, split them */
1580 #define FOLL_HWPOISON   0x100   /* check page is hwpoisoned */
1581 
1582 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
1583                         void *data);
1584 extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
1585                                unsigned long size, pte_fn_t fn, void *data);
1586 
1587 #ifdef CONFIG_PROC_FS
1588 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
1589 #else
1590 static inline void vm_stat_account(struct mm_struct *mm,
1591                         unsigned long flags, struct file *file, long pages)
1592 {
1593 }
1594 #endif /* CONFIG_PROC_FS */
1595 
1596 #ifdef CONFIG_DEBUG_PAGEALLOC
1597 extern int debug_pagealloc_enabled;
1598 
1599 extern void kernel_map_pages(struct page *page, int numpages, int enable);
1600 
1601 static inline void enable_debug_pagealloc(void)
1602 {
1603         debug_pagealloc_enabled = 1;
1604 }
1605 #ifdef CONFIG_HIBERNATION
1606 extern bool kernel_page_present(struct page *page);
1607 #endif /* CONFIG_HIBERNATION */
1608 #else
1609 static inline void
1610 kernel_map_pages(struct page *page, int numpages, int enable) {}
1611 static inline void enable_debug_pagealloc(void)
1612 {
1613 }
1614 #ifdef CONFIG_HIBERNATION
1615 static inline bool kernel_page_present(struct page *page) { return true; }
1616 #endif /* CONFIG_HIBERNATION */
1617 #endif
1618 
1619 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
1620 #ifdef  __HAVE_ARCH_GATE_AREA
1621 int in_gate_area_no_mm(unsigned long addr);
1622 int in_gate_area(struct mm_struct *mm, unsigned long addr);
1623 #else
1624 int in_gate_area_no_mm(unsigned long addr);
1625 #define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
1626 #endif  /* __HAVE_ARCH_GATE_AREA */
1627 
1628 int drop_caches_sysctl_handler(struct ctl_table *, int,
1629                                         void __user *, size_t *, loff_t *);
1630 unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
1631                         unsigned long lru_pages);
1632 
1633 #ifndef CONFIG_MMU
1634 #define randomize_va_space 0
1635 #else
1636 extern int randomize_va_space;
1637 #endif
1638 
1639 const char * arch_vma_name(struct vm_area_struct *vma);
1640 void print_vma_addr(char *prefix, unsigned long rip);
1641 
1642 void sparse_mem_maps_populate_node(struct page **map_map,
1643                                    unsigned long pnum_begin,
1644                                    unsigned long pnum_end,
1645                                    unsigned long map_count,
1646                                    int nodeid);
1647 
1648 struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
1649 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
1650 pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
1651 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
1652 pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
1653 void *vmemmap_alloc_block(unsigned long size, int node);
1654 void *vmemmap_alloc_block_buf(unsigned long size, int node);
1655 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
1656 int vmemmap_populate_basepages(struct page *start_page,
1657                                                 unsigned long pages, int node);
1658 int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
1659 void vmemmap_populate_print_last(void);
1660 
1661 
1662 enum mf_flags {
1663         MF_COUNT_INCREASED = 1 << 0,
1664 };
1665 extern void memory_failure(unsigned long pfn, int trapno);
1666 extern int __memory_failure(unsigned long pfn, int trapno, int flags);
1667 extern int unpoison_memory(unsigned long pfn);
1668 extern int sysctl_memory_failure_early_kill;
1669 extern int sysctl_memory_failure_recovery;
1670 extern void shake_page(struct page *p, int access);
1671 extern atomic_long_t mce_bad_pages;
1672 extern int soft_offline_page(struct page *page, int flags);
1673 
1674 extern void dump_page(struct page *page);
1675 
1676 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
1677 extern void clear_huge_page(struct page *page,
1678                             unsigned long addr,
1679                             unsigned int pages_per_huge_page);
1680 extern void copy_user_huge_page(struct page *dst, struct page *src,
1681                                 unsigned long addr, struct vm_area_struct *vma,
1682                                 unsigned int pages_per_huge_page);
1683 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
1684 
1685 #endif /* __KERNEL__ */
1686 #endif /* _LINUX_MM_H */
1687 

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