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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 
 22 struct mempolicy;
 23 struct anon_vma;
 24 struct anon_vma_chain;
 25 struct file_ra_state;
 26 struct user_struct;
 27 struct writeback_control;
 28 
 29 #ifndef CONFIG_NEED_MULTIPLE_NODES      /* Don't use mapnrs, do it properly */
 30 extern unsigned long max_mapnr;
 31 
 32 static inline void set_max_mapnr(unsigned long limit)
 33 {
 34         max_mapnr = limit;
 35 }
 36 #else
 37 static inline void set_max_mapnr(unsigned long limit) { }
 38 #endif
 39 
 40 extern unsigned long totalram_pages;
 41 extern void * high_memory;
 42 extern int page_cluster;
 43 
 44 #ifdef CONFIG_SYSCTL
 45 extern int sysctl_legacy_va_layout;
 46 #else
 47 #define sysctl_legacy_va_layout 0
 48 #endif
 49 
 50 #include <asm/page.h>
 51 #include <asm/pgtable.h>
 52 #include <asm/processor.h>
 53 
 54 #ifndef __pa_symbol
 55 #define __pa_symbol(x)  __pa(RELOC_HIDE((unsigned long)(x), 0))
 56 #endif
 57 
 58 extern unsigned long sysctl_user_reserve_kbytes;
 59 extern unsigned long sysctl_admin_reserve_kbytes;
 60 
 61 extern int sysctl_overcommit_memory;
 62 extern int sysctl_overcommit_ratio;
 63 extern unsigned long sysctl_overcommit_kbytes;
 64 
 65 extern int overcommit_ratio_handler(struct ctl_table *, int, void __user *,
 66                                     size_t *, loff_t *);
 67 extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
 68                                     size_t *, loff_t *);
 69 
 70 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
 71 
 72 /* to align the pointer to the (next) page boundary */
 73 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
 74 
 75 /* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
 76 #define PAGE_ALIGNED(addr)      IS_ALIGNED((unsigned long)addr, PAGE_SIZE)
 77 
 78 /*
 79  * Linux kernel virtual memory manager primitives.
 80  * The idea being to have a "virtual" mm in the same way
 81  * we have a virtual fs - giving a cleaner interface to the
 82  * mm details, and allowing different kinds of memory mappings
 83  * (from shared memory to executable loading to arbitrary
 84  * mmap() functions).
 85  */
 86 
 87 extern struct kmem_cache *vm_area_cachep;
 88 
 89 #ifndef CONFIG_MMU
 90 extern struct rb_root nommu_region_tree;
 91 extern struct rw_semaphore nommu_region_sem;
 92 
 93 extern unsigned int kobjsize(const void *objp);
 94 #endif
 95 
 96 /*
 97  * vm_flags in vm_area_struct, see mm_types.h.
 98  */
 99 #define VM_NONE         0x00000000
100 
101 #define VM_READ         0x00000001      /* currently active flags */
102 #define VM_WRITE        0x00000002
103 #define VM_EXEC         0x00000004
104 #define VM_SHARED       0x00000008
105 
106 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
107 #define VM_MAYREAD      0x00000010      /* limits for mprotect() etc */
108 #define VM_MAYWRITE     0x00000020
109 #define VM_MAYEXEC      0x00000040
110 #define VM_MAYSHARE     0x00000080
111 
112 #define VM_GROWSDOWN    0x00000100      /* general info on the segment */
113 #define VM_PFNMAP       0x00000400      /* Page-ranges managed without "struct page", just pure PFN */
114 #define VM_DENYWRITE    0x00000800      /* ETXTBSY on write attempts.. */
115 
116 #define VM_LOCKED       0x00002000
117 #define VM_IO           0x00004000      /* Memory mapped I/O or similar */
118 
119                                         /* Used by sys_madvise() */
120 #define VM_SEQ_READ     0x00008000      /* App will access data sequentially */
121 #define VM_RAND_READ    0x00010000      /* App will not benefit from clustered reads */
122 
123 #define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
124 #define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
125 #define VM_ACCOUNT      0x00100000      /* Is a VM accounted object */
126 #define VM_NORESERVE    0x00200000      /* should the VM suppress accounting */
127 #define VM_HUGETLB      0x00400000      /* Huge TLB Page VM */
128 #define VM_NONLINEAR    0x00800000      /* Is non-linear (remap_file_pages) */
129 #define VM_ARCH_1       0x01000000      /* Architecture-specific flag */
130 #define VM_DONTDUMP     0x04000000      /* Do not include in the core dump */
131 
132 #ifdef CONFIG_MEM_SOFT_DIRTY
133 # define VM_SOFTDIRTY   0x08000000      /* Not soft dirty clean area */
134 #else
135 # define VM_SOFTDIRTY   0
136 #endif
137 
138 #define VM_MIXEDMAP     0x10000000      /* Can contain "struct page" and pure PFN pages */
139 #define VM_HUGEPAGE     0x20000000      /* MADV_HUGEPAGE marked this vma */
140 #define VM_NOHUGEPAGE   0x40000000      /* MADV_NOHUGEPAGE marked this vma */
141 #define VM_MERGEABLE    0x80000000      /* KSM may merge identical pages */
142 
143 #if defined(CONFIG_X86)
144 # define VM_PAT         VM_ARCH_1       /* PAT reserves whole VMA at once (x86) */
145 #elif defined(CONFIG_PPC)
146 # define VM_SAO         VM_ARCH_1       /* Strong Access Ordering (powerpc) */
147 #elif defined(CONFIG_PARISC)
148 # define VM_GROWSUP     VM_ARCH_1
149 #elif defined(CONFIG_METAG)
150 # define VM_GROWSUP     VM_ARCH_1
151 #elif defined(CONFIG_IA64)
152 # define VM_GROWSUP     VM_ARCH_1
153 #elif !defined(CONFIG_MMU)
154 # define VM_MAPPED_COPY VM_ARCH_1       /* T if mapped copy of data (nommu mmap) */
155 #endif
156 
157 #ifndef VM_GROWSUP
158 # define VM_GROWSUP     VM_NONE
159 #endif
160 
161 /* Bits set in the VMA until the stack is in its final location */
162 #define VM_STACK_INCOMPLETE_SETUP       (VM_RAND_READ | VM_SEQ_READ)
163 
164 #ifndef VM_STACK_DEFAULT_FLAGS          /* arch can override this */
165 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
166 #endif
167 
168 #ifdef CONFIG_STACK_GROWSUP
169 #define VM_STACK_FLAGS  (VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
170 #else
171 #define VM_STACK_FLAGS  (VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
172 #endif
173 
174 /*
175  * Special vmas that are non-mergable, non-mlock()able.
176  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
177  */
178 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
179 
180 /*
181  * mapping from the currently active vm_flags protection bits (the
182  * low four bits) to a page protection mask..
183  */
184 extern pgprot_t protection_map[16];
185 
186 #define FAULT_FLAG_WRITE        0x01    /* Fault was a write access */
187 #define FAULT_FLAG_NONLINEAR    0x02    /* Fault was via a nonlinear mapping */
188 #define FAULT_FLAG_MKWRITE      0x04    /* Fault was mkwrite of existing pte */
189 #define FAULT_FLAG_ALLOW_RETRY  0x08    /* Retry fault if blocking */
190 #define FAULT_FLAG_RETRY_NOWAIT 0x10    /* Don't drop mmap_sem and wait when retrying */
191 #define FAULT_FLAG_KILLABLE     0x20    /* The fault task is in SIGKILL killable region */
192 #define FAULT_FLAG_TRIED        0x40    /* second try */
193 #define FAULT_FLAG_USER         0x80    /* The fault originated in userspace */
194 
195 /*
196  * vm_fault is filled by the the pagefault handler and passed to the vma's
197  * ->fault function. The vma's ->fault is responsible for returning a bitmask
198  * of VM_FAULT_xxx flags that give details about how the fault was handled.
199  *
200  * pgoff should be used in favour of virtual_address, if possible. If pgoff
201  * is used, one may implement ->remap_pages to get nonlinear mapping support.
202  */
203 struct vm_fault {
204         unsigned int flags;             /* FAULT_FLAG_xxx flags */
205         pgoff_t pgoff;                  /* Logical page offset based on vma */
206         void __user *virtual_address;   /* Faulting virtual address */
207 
208         struct page *page;              /* ->fault handlers should return a
209                                          * page here, unless VM_FAULT_NOPAGE
210                                          * is set (which is also implied by
211                                          * VM_FAULT_ERROR).
212                                          */
213 };
214 
215 /*
216  * These are the virtual MM functions - opening of an area, closing and
217  * unmapping it (needed to keep files on disk up-to-date etc), pointer
218  * to the functions called when a no-page or a wp-page exception occurs. 
219  */
220 struct vm_operations_struct {
221         void (*open)(struct vm_area_struct * area);
222         void (*close)(struct vm_area_struct * area);
223         int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
224 
225         /* notification that a previously read-only page is about to become
226          * writable, if an error is returned it will cause a SIGBUS */
227         int (*page_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
228 
229         /* called by access_process_vm when get_user_pages() fails, typically
230          * for use by special VMAs that can switch between memory and hardware
231          */
232         int (*access)(struct vm_area_struct *vma, unsigned long addr,
233                       void *buf, int len, int write);
234 #ifdef CONFIG_NUMA
235         /*
236          * set_policy() op must add a reference to any non-NULL @new mempolicy
237          * to hold the policy upon return.  Caller should pass NULL @new to
238          * remove a policy and fall back to surrounding context--i.e. do not
239          * install a MPOL_DEFAULT policy, nor the task or system default
240          * mempolicy.
241          */
242         int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
243 
244         /*
245          * get_policy() op must add reference [mpol_get()] to any policy at
246          * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
247          * in mm/mempolicy.c will do this automatically.
248          * get_policy() must NOT add a ref if the policy at (vma,addr) is not
249          * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
250          * If no [shared/vma] mempolicy exists at the addr, get_policy() op
251          * must return NULL--i.e., do not "fallback" to task or system default
252          * policy.
253          */
254         struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
255                                         unsigned long addr);
256         int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
257                 const nodemask_t *to, unsigned long flags);
258 #endif
259         /* called by sys_remap_file_pages() to populate non-linear mapping */
260         int (*remap_pages)(struct vm_area_struct *vma, unsigned long addr,
261                            unsigned long size, pgoff_t pgoff);
262 };
263 
264 struct mmu_gather;
265 struct inode;
266 
267 #define page_private(page)              ((page)->private)
268 #define set_page_private(page, v)       ((page)->private = (v))
269 
270 /* It's valid only if the page is free path or free_list */
271 static inline void set_freepage_migratetype(struct page *page, int migratetype)
272 {
273         page->index = migratetype;
274 }
275 
276 /* It's valid only if the page is free path or free_list */
277 static inline int get_freepage_migratetype(struct page *page)
278 {
279         return page->index;
280 }
281 
282 /*
283  * FIXME: take this include out, include page-flags.h in
284  * files which need it (119 of them)
285  */
286 #include <linux/page-flags.h>
287 #include <linux/huge_mm.h>
288 
289 /*
290  * Methods to modify the page usage count.
291  *
292  * What counts for a page usage:
293  * - cache mapping   (page->mapping)
294  * - private data    (page->private)
295  * - page mapped in a task's page tables, each mapping
296  *   is counted separately
297  *
298  * Also, many kernel routines increase the page count before a critical
299  * routine so they can be sure the page doesn't go away from under them.
300  */
301 
302 /*
303  * Drop a ref, return true if the refcount fell to zero (the page has no users)
304  */
305 static inline int put_page_testzero(struct page *page)
306 {
307         VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0, page);
308         return atomic_dec_and_test(&page->_count);
309 }
310 
311 /*
312  * Try to grab a ref unless the page has a refcount of zero, return false if
313  * that is the case.
314  * This can be called when MMU is off so it must not access
315  * any of the virtual mappings.
316  */
317 static inline int get_page_unless_zero(struct page *page)
318 {
319         return atomic_inc_not_zero(&page->_count);
320 }
321 
322 /*
323  * Try to drop a ref unless the page has a refcount of one, return false if
324  * that is the case.
325  * This is to make sure that the refcount won't become zero after this drop.
326  * This can be called when MMU is off so it must not access
327  * any of the virtual mappings.
328  */
329 static inline int put_page_unless_one(struct page *page)
330 {
331         return atomic_add_unless(&page->_count, -1, 1);
332 }
333 
334 extern int page_is_ram(unsigned long pfn);
335 
336 /* Support for virtually mapped pages */
337 struct page *vmalloc_to_page(const void *addr);
338 unsigned long vmalloc_to_pfn(const void *addr);
339 
340 /*
341  * Determine if an address is within the vmalloc range
342  *
343  * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
344  * is no special casing required.
345  */
346 static inline int is_vmalloc_addr(const void *x)
347 {
348 #ifdef CONFIG_MMU
349         unsigned long addr = (unsigned long)x;
350 
351         return addr >= VMALLOC_START && addr < VMALLOC_END;
352 #else
353         return 0;
354 #endif
355 }
356 #ifdef CONFIG_MMU
357 extern int is_vmalloc_or_module_addr(const void *x);
358 #else
359 static inline int is_vmalloc_or_module_addr(const void *x)
360 {
361         return 0;
362 }
363 #endif
364 
365 static inline void compound_lock(struct page *page)
366 {
367 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
368         VM_BUG_ON_PAGE(PageSlab(page), page);
369         bit_spin_lock(PG_compound_lock, &page->flags);
370 #endif
371 }
372 
373 static inline void compound_unlock(struct page *page)
374 {
375 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
376         VM_BUG_ON_PAGE(PageSlab(page), page);
377         bit_spin_unlock(PG_compound_lock, &page->flags);
378 #endif
379 }
380 
381 static inline unsigned long compound_lock_irqsave(struct page *page)
382 {
383         unsigned long uninitialized_var(flags);
384 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
385         local_irq_save(flags);
386         compound_lock(page);
387 #endif
388         return flags;
389 }
390 
391 static inline void compound_unlock_irqrestore(struct page *page,
392                                               unsigned long flags)
393 {
394 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
395         compound_unlock(page);
396         local_irq_restore(flags);
397 #endif
398 }
399 
400 static inline struct page *compound_head(struct page *page)
401 {
402         if (unlikely(PageTail(page))) {
403                 struct page *head = page->first_page;
404 
405                 /*
406                  * page->first_page may be a dangling pointer to an old
407                  * compound page, so recheck that it is still a tail
408                  * page before returning.
409                  */
410                 smp_rmb();
411                 if (likely(PageTail(page)))
412                         return head;
413         }
414         return page;
415 }
416 
417 /*
418  * The atomic page->_mapcount, starts from -1: so that transitions
419  * both from it and to it can be tracked, using atomic_inc_and_test
420  * and atomic_add_negative(-1).
421  */
422 static inline void page_mapcount_reset(struct page *page)
423 {
424         atomic_set(&(page)->_mapcount, -1);
425 }
426 
427 static inline int page_mapcount(struct page *page)
428 {
429         return atomic_read(&(page)->_mapcount) + 1;
430 }
431 
432 static inline int page_count(struct page *page)
433 {
434         return atomic_read(&compound_head(page)->_count);
435 }
436 
437 #ifdef CONFIG_HUGETLB_PAGE
438 extern int PageHeadHuge(struct page *page_head);
439 #else /* CONFIG_HUGETLB_PAGE */
440 static inline int PageHeadHuge(struct page *page_head)
441 {
442         return 0;
443 }
444 #endif /* CONFIG_HUGETLB_PAGE */
445 
446 static inline bool __compound_tail_refcounted(struct page *page)
447 {
448         return !PageSlab(page) && !PageHeadHuge(page);
449 }
450 
451 /*
452  * This takes a head page as parameter and tells if the
453  * tail page reference counting can be skipped.
454  *
455  * For this to be safe, PageSlab and PageHeadHuge must remain true on
456  * any given page where they return true here, until all tail pins
457  * have been released.
458  */
459 static inline bool compound_tail_refcounted(struct page *page)
460 {
461         VM_BUG_ON_PAGE(!PageHead(page), page);
462         return __compound_tail_refcounted(page);
463 }
464 
465 static inline void get_huge_page_tail(struct page *page)
466 {
467         /*
468          * __split_huge_page_refcount() cannot run from under us.
469          */
470         VM_BUG_ON_PAGE(!PageTail(page), page);
471         VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
472         VM_BUG_ON_PAGE(atomic_read(&page->_count) != 0, page);
473         if (compound_tail_refcounted(page->first_page))
474                 atomic_inc(&page->_mapcount);
475 }
476 
477 extern bool __get_page_tail(struct page *page);
478 
479 static inline void get_page(struct page *page)
480 {
481         if (unlikely(PageTail(page)))
482                 if (likely(__get_page_tail(page)))
483                         return;
484         /*
485          * Getting a normal page or the head of a compound page
486          * requires to already have an elevated page->_count.
487          */
488         VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);
489         atomic_inc(&page->_count);
490 }
491 
492 static inline struct page *virt_to_head_page(const void *x)
493 {
494         struct page *page = virt_to_page(x);
495         return compound_head(page);
496 }
497 
498 /*
499  * Setup the page count before being freed into the page allocator for
500  * the first time (boot or memory hotplug)
501  */
502 static inline void init_page_count(struct page *page)
503 {
504         atomic_set(&page->_count, 1);
505 }
506 
507 /*
508  * PageBuddy() indicate that the page is free and in the buddy system
509  * (see mm/page_alloc.c).
510  *
511  * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to
512  * -2 so that an underflow of the page_mapcount() won't be mistaken
513  * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very
514  * efficiently by most CPU architectures.
515  */
516 #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
517 
518 static inline int PageBuddy(struct page *page)
519 {
520         return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE;
521 }
522 
523 static inline void __SetPageBuddy(struct page *page)
524 {
525         VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
526         atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
527 }
528 
529 static inline void __ClearPageBuddy(struct page *page)
530 {
531         VM_BUG_ON_PAGE(!PageBuddy(page), page);
532         atomic_set(&page->_mapcount, -1);
533 }
534 
535 void put_page(struct page *page);
536 void put_pages_list(struct list_head *pages);
537 
538 void split_page(struct page *page, unsigned int order);
539 int split_free_page(struct page *page);
540 
541 /*
542  * Compound pages have a destructor function.  Provide a
543  * prototype for that function and accessor functions.
544  * These are _only_ valid on the head of a PG_compound page.
545  */
546 typedef void compound_page_dtor(struct page *);
547 
548 static inline void set_compound_page_dtor(struct page *page,
549                                                 compound_page_dtor *dtor)
550 {
551         page[1].lru.next = (void *)dtor;
552 }
553 
554 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
555 {
556         return (compound_page_dtor *)page[1].lru.next;
557 }
558 
559 static inline int compound_order(struct page *page)
560 {
561         if (!PageHead(page))
562                 return 0;
563         return (unsigned long)page[1].lru.prev;
564 }
565 
566 static inline void set_compound_order(struct page *page, unsigned long order)
567 {
568         page[1].lru.prev = (void *)order;
569 }
570 
571 #ifdef CONFIG_MMU
572 /*
573  * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
574  * servicing faults for write access.  In the normal case, do always want
575  * pte_mkwrite.  But get_user_pages can cause write faults for mappings
576  * that do not have writing enabled, when used by access_process_vm.
577  */
578 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
579 {
580         if (likely(vma->vm_flags & VM_WRITE))
581                 pte = pte_mkwrite(pte);
582         return pte;
583 }
584 #endif
585 
586 /*
587  * Multiple processes may "see" the same page. E.g. for untouched
588  * mappings of /dev/null, all processes see the same page full of
589  * zeroes, and text pages of executables and shared libraries have
590  * only one copy in memory, at most, normally.
591  *
592  * For the non-reserved pages, page_count(page) denotes a reference count.
593  *   page_count() == 0 means the page is free. page->lru is then used for
594  *   freelist management in the buddy allocator.
595  *   page_count() > 0  means the page has been allocated.
596  *
597  * Pages are allocated by the slab allocator in order to provide memory
598  * to kmalloc and kmem_cache_alloc. In this case, the management of the
599  * page, and the fields in 'struct page' are the responsibility of mm/slab.c
600  * unless a particular usage is carefully commented. (the responsibility of
601  * freeing the kmalloc memory is the caller's, of course).
602  *
603  * A page may be used by anyone else who does a __get_free_page().
604  * In this case, page_count still tracks the references, and should only
605  * be used through the normal accessor functions. The top bits of page->flags
606  * and page->virtual store page management information, but all other fields
607  * are unused and could be used privately, carefully. The management of this
608  * page is the responsibility of the one who allocated it, and those who have
609  * subsequently been given references to it.
610  *
611  * The other pages (we may call them "pagecache pages") are completely
612  * managed by the Linux memory manager: I/O, buffers, swapping etc.
613  * The following discussion applies only to them.
614  *
615  * A pagecache page contains an opaque `private' member, which belongs to the
616  * page's address_space. Usually, this is the address of a circular list of
617  * the page's disk buffers. PG_private must be set to tell the VM to call
618  * into the filesystem to release these pages.
619  *
620  * A page may belong to an inode's memory mapping. In this case, page->mapping
621  * is the pointer to the inode, and page->index is the file offset of the page,
622  * in units of PAGE_CACHE_SIZE.
623  *
624  * If pagecache pages are not associated with an inode, they are said to be
625  * anonymous pages. These may become associated with the swapcache, and in that
626  * case PG_swapcache is set, and page->private is an offset into the swapcache.
627  *
628  * In either case (swapcache or inode backed), the pagecache itself holds one
629  * reference to the page. Setting PG_private should also increment the
630  * refcount. The each user mapping also has a reference to the page.
631  *
632  * The pagecache pages are stored in a per-mapping radix tree, which is
633  * rooted at mapping->page_tree, and indexed by offset.
634  * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
635  * lists, we instead now tag pages as dirty/writeback in the radix tree.
636  *
637  * All pagecache pages may be subject to I/O:
638  * - inode pages may need to be read from disk,
639  * - inode pages which have been modified and are MAP_SHARED may need
640  *   to be written back to the inode on disk,
641  * - anonymous pages (including MAP_PRIVATE file mappings) which have been
642  *   modified may need to be swapped out to swap space and (later) to be read
643  *   back into memory.
644  */
645 
646 /*
647  * The zone field is never updated after free_area_init_core()
648  * sets it, so none of the operations on it need to be atomic.
649  */
650 
651 /* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
652 #define SECTIONS_PGOFF          ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
653 #define NODES_PGOFF             (SECTIONS_PGOFF - NODES_WIDTH)
654 #define ZONES_PGOFF             (NODES_PGOFF - ZONES_WIDTH)
655 #define LAST_CPUPID_PGOFF       (ZONES_PGOFF - LAST_CPUPID_WIDTH)
656 
657 /*
658  * Define the bit shifts to access each section.  For non-existent
659  * sections we define the shift as 0; that plus a 0 mask ensures
660  * the compiler will optimise away reference to them.
661  */
662 #define SECTIONS_PGSHIFT        (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
663 #define NODES_PGSHIFT           (NODES_PGOFF * (NODES_WIDTH != 0))
664 #define ZONES_PGSHIFT           (ZONES_PGOFF * (ZONES_WIDTH != 0))
665 #define LAST_CPUPID_PGSHIFT     (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
666 
667 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
668 #ifdef NODE_NOT_IN_PAGE_FLAGS
669 #define ZONEID_SHIFT            (SECTIONS_SHIFT + ZONES_SHIFT)
670 #define ZONEID_PGOFF            ((SECTIONS_PGOFF < ZONES_PGOFF)? \
671                                                 SECTIONS_PGOFF : ZONES_PGOFF)
672 #else
673 #define ZONEID_SHIFT            (NODES_SHIFT + ZONES_SHIFT)
674 #define ZONEID_PGOFF            ((NODES_PGOFF < ZONES_PGOFF)? \
675                                                 NODES_PGOFF : ZONES_PGOFF)
676 #endif
677 
678 #define ZONEID_PGSHIFT          (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
679 
680 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
681 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
682 #endif
683 
684 #define ZONES_MASK              ((1UL << ZONES_WIDTH) - 1)
685 #define NODES_MASK              ((1UL << NODES_WIDTH) - 1)
686 #define SECTIONS_MASK           ((1UL << SECTIONS_WIDTH) - 1)
687 #define LAST_CPUPID_MASK        ((1UL << LAST_CPUPID_WIDTH) - 1)
688 #define ZONEID_MASK             ((1UL << ZONEID_SHIFT) - 1)
689 
690 static inline enum zone_type page_zonenum(const struct page *page)
691 {
692         return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
693 }
694 
695 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
696 #define SECTION_IN_PAGE_FLAGS
697 #endif
698 
699 /*
700  * The identification function is mainly used by the buddy allocator for
701  * determining if two pages could be buddies. We are not really identifying
702  * the zone since we could be using the section number id if we do not have
703  * node id available in page flags.
704  * We only guarantee that it will return the same value for two combinable
705  * pages in a zone.
706  */
707 static inline int page_zone_id(struct page *page)
708 {
709         return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
710 }
711 
712 static inline int zone_to_nid(struct zone *zone)
713 {
714 #ifdef CONFIG_NUMA
715         return zone->node;
716 #else
717         return 0;
718 #endif
719 }
720 
721 #ifdef NODE_NOT_IN_PAGE_FLAGS
722 extern int page_to_nid(const struct page *page);
723 #else
724 static inline int page_to_nid(const struct page *page)
725 {
726         return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
727 }
728 #endif
729 
730 #ifdef CONFIG_NUMA_BALANCING
731 static inline int cpu_pid_to_cpupid(int cpu, int pid)
732 {
733         return ((cpu & LAST__CPU_MASK) << LAST__PID_SHIFT) | (pid & LAST__PID_MASK);
734 }
735 
736 static inline int cpupid_to_pid(int cpupid)
737 {
738         return cpupid & LAST__PID_MASK;
739 }
740 
741 static inline int cpupid_to_cpu(int cpupid)
742 {
743         return (cpupid >> LAST__PID_SHIFT) & LAST__CPU_MASK;
744 }
745 
746 static inline int cpupid_to_nid(int cpupid)
747 {
748         return cpu_to_node(cpupid_to_cpu(cpupid));
749 }
750 
751 static inline bool cpupid_pid_unset(int cpupid)
752 {
753         return cpupid_to_pid(cpupid) == (-1 & LAST__PID_MASK);
754 }
755 
756 static inline bool cpupid_cpu_unset(int cpupid)
757 {
758         return cpupid_to_cpu(cpupid) == (-1 & LAST__CPU_MASK);
759 }
760 
761 static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
762 {
763         return (task_pid & LAST__PID_MASK) == cpupid_to_pid(cpupid);
764 }
765 
766 #define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
767 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
768 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
769 {
770         return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
771 }
772 
773 static inline int page_cpupid_last(struct page *page)
774 {
775         return page->_last_cpupid;
776 }
777 static inline void page_cpupid_reset_last(struct page *page)
778 {
779         page->_last_cpupid = -1 & LAST_CPUPID_MASK;
780 }
781 #else
782 static inline int page_cpupid_last(struct page *page)
783 {
784         return (page->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
785 }
786 
787 extern int page_cpupid_xchg_last(struct page *page, int cpupid);
788 
789 static inline void page_cpupid_reset_last(struct page *page)
790 {
791         int cpupid = (1 << LAST_CPUPID_SHIFT) - 1;
792 
793         page->flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
794         page->flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
795 }
796 #endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
797 #else /* !CONFIG_NUMA_BALANCING */
798 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
799 {
800         return page_to_nid(page); /* XXX */
801 }
802 
803 static inline int page_cpupid_last(struct page *page)
804 {
805         return page_to_nid(page); /* XXX */
806 }
807 
808 static inline int cpupid_to_nid(int cpupid)
809 {
810         return -1;
811 }
812 
813 static inline int cpupid_to_pid(int cpupid)
814 {
815         return -1;
816 }
817 
818 static inline int cpupid_to_cpu(int cpupid)
819 {
820         return -1;
821 }
822 
823 static inline int cpu_pid_to_cpupid(int nid, int pid)
824 {
825         return -1;
826 }
827 
828 static inline bool cpupid_pid_unset(int cpupid)
829 {
830         return 1;
831 }
832 
833 static inline void page_cpupid_reset_last(struct page *page)
834 {
835 }
836 
837 static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
838 {
839         return false;
840 }
841 #endif /* CONFIG_NUMA_BALANCING */
842 
843 static inline struct zone *page_zone(const struct page *page)
844 {
845         return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
846 }
847 
848 #ifdef SECTION_IN_PAGE_FLAGS
849 static inline void set_page_section(struct page *page, unsigned long section)
850 {
851         page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
852         page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
853 }
854 
855 static inline unsigned long page_to_section(const struct page *page)
856 {
857         return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
858 }
859 #endif
860 
861 static inline void set_page_zone(struct page *page, enum zone_type zone)
862 {
863         page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
864         page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
865 }
866 
867 static inline void set_page_node(struct page *page, unsigned long node)
868 {
869         page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
870         page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
871 }
872 
873 static inline void set_page_links(struct page *page, enum zone_type zone,
874         unsigned long node, unsigned long pfn)
875 {
876         set_page_zone(page, zone);
877         set_page_node(page, node);
878 #ifdef SECTION_IN_PAGE_FLAGS
879         set_page_section(page, pfn_to_section_nr(pfn));
880 #endif
881 }
882 
883 /*
884  * Some inline functions in vmstat.h depend on page_zone()
885  */
886 #include <linux/vmstat.h>
887 
888 static __always_inline void *lowmem_page_address(const struct page *page)
889 {
890         return __va(PFN_PHYS(page_to_pfn(page)));
891 }
892 
893 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
894 #define HASHED_PAGE_VIRTUAL
895 #endif
896 
897 #if defined(WANT_PAGE_VIRTUAL)
898 static inline void *page_address(const struct page *page)
899 {
900         return page->virtual;
901 }
902 static inline void set_page_address(struct page *page, void *address)
903 {
904         page->virtual = address;
905 }
906 #define page_address_init()  do { } while(0)
907 #endif
908 
909 #if defined(HASHED_PAGE_VIRTUAL)
910 void *page_address(const struct page *page);
911 void set_page_address(struct page *page, void *virtual);
912 void page_address_init(void);
913 #endif
914 
915 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
916 #define page_address(page) lowmem_page_address(page)
917 #define set_page_address(page, address)  do { } while(0)
918 #define page_address_init()  do { } while(0)
919 #endif
920 
921 /*
922  * On an anonymous page mapped into a user virtual memory area,
923  * page->mapping points to its anon_vma, not to a struct address_space;
924  * with the PAGE_MAPPING_ANON bit set to distinguish it.  See rmap.h.
925  *
926  * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
927  * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
928  * and then page->mapping points, not to an anon_vma, but to a private
929  * structure which KSM associates with that merged page.  See ksm.h.
930  *
931  * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
932  *
933  * Please note that, confusingly, "page_mapping" refers to the inode
934  * address_space which maps the page from disk; whereas "page_mapped"
935  * refers to user virtual address space into which the page is mapped.
936  */
937 #define PAGE_MAPPING_ANON       1
938 #define PAGE_MAPPING_KSM        2
939 #define PAGE_MAPPING_FLAGS      (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
940 
941 extern struct address_space *page_mapping(struct page *page);
942 
943 /* Neutral page->mapping pointer to address_space or anon_vma or other */
944 static inline void *page_rmapping(struct page *page)
945 {
946         return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS);
947 }
948 
949 extern struct address_space *__page_file_mapping(struct page *);
950 
951 static inline
952 struct address_space *page_file_mapping(struct page *page)
953 {
954         if (unlikely(PageSwapCache(page)))
955                 return __page_file_mapping(page);
956 
957         return page->mapping;
958 }
959 
960 static inline int PageAnon(struct page *page)
961 {
962         return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
963 }
964 
965 /*
966  * Return the pagecache index of the passed page.  Regular pagecache pages
967  * use ->index whereas swapcache pages use ->private
968  */
969 static inline pgoff_t page_index(struct page *page)
970 {
971         if (unlikely(PageSwapCache(page)))
972                 return page_private(page);
973         return page->index;
974 }
975 
976 extern pgoff_t __page_file_index(struct page *page);
977 
978 /*
979  * Return the file index of the page. Regular pagecache pages use ->index
980  * whereas swapcache pages use swp_offset(->private)
981  */
982 static inline pgoff_t page_file_index(struct page *page)
983 {
984         if (unlikely(PageSwapCache(page)))
985                 return __page_file_index(page);
986 
987         return page->index;
988 }
989 
990 /*
991  * Return true if this page is mapped into pagetables.
992  */
993 static inline int page_mapped(struct page *page)
994 {
995         return atomic_read(&(page)->_mapcount) >= 0;
996 }
997 
998 /*
999  * Different kinds of faults, as returned by handle_mm_fault().
1000  * Used to decide whether a process gets delivered SIGBUS or
1001  * just gets major/minor fault counters bumped up.
1002  */
1003 
1004 #define VM_FAULT_MINOR  0 /* For backwards compat. Remove me quickly. */
1005 
1006 #define VM_FAULT_OOM    0x0001
1007 #define VM_FAULT_SIGBUS 0x0002
1008 #define VM_FAULT_MAJOR  0x0004
1009 #define VM_FAULT_WRITE  0x0008  /* Special case for get_user_pages */
1010 #define VM_FAULT_HWPOISON 0x0010        /* Hit poisoned small page */
1011 #define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
1012 
1013 #define VM_FAULT_NOPAGE 0x0100  /* ->fault installed the pte, not return page */
1014 #define VM_FAULT_LOCKED 0x0200  /* ->fault locked the returned page */
1015 #define VM_FAULT_RETRY  0x0400  /* ->fault blocked, must retry */
1016 #define VM_FAULT_FALLBACK 0x0800        /* huge page fault failed, fall back to small */
1017 
1018 #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */
1019 
1020 #define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON | \
1021                          VM_FAULT_FALLBACK | VM_FAULT_HWPOISON_LARGE)
1022 
1023 /* Encode hstate index for a hwpoisoned large page */
1024 #define VM_FAULT_SET_HINDEX(x) ((x) << 12)
1025 #define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
1026 
1027 /*
1028  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
1029  */
1030 extern void pagefault_out_of_memory(void);
1031 
1032 #define offset_in_page(p)       ((unsigned long)(p) & ~PAGE_MASK)
1033 
1034 /*
1035  * Flags passed to show_mem() and show_free_areas() to suppress output in
1036  * various contexts.
1037  */
1038 #define SHOW_MEM_FILTER_NODES           (0x0001u)       /* disallowed nodes */
1039 
1040 extern void show_free_areas(unsigned int flags);
1041 extern bool skip_free_areas_node(unsigned int flags, int nid);
1042 
1043 int shmem_zero_setup(struct vm_area_struct *);
1044 
1045 extern int can_do_mlock(void);
1046 extern int user_shm_lock(size_t, struct user_struct *);
1047 extern void user_shm_unlock(size_t, struct user_struct *);
1048 
1049 /*
1050  * Parameter block passed down to zap_pte_range in exceptional cases.
1051  */
1052 struct zap_details {
1053         struct vm_area_struct *nonlinear_vma;   /* Check page->index if set */
1054         struct address_space *check_mapping;    /* Check page->mapping if set */
1055         pgoff_t first_index;                    /* Lowest page->index to unmap */
1056         pgoff_t last_index;                     /* Highest page->index to unmap */
1057 };
1058 
1059 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
1060                 pte_t pte);
1061 
1062 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1063                 unsigned long size);
1064 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
1065                 unsigned long size, struct zap_details *);
1066 void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
1067                 unsigned long start, unsigned long end);
1068 
1069 /**
1070  * mm_walk - callbacks for walk_page_range
1071  * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
1072  * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
1073  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
1074  *             this handler is required to be able to handle
1075  *             pmd_trans_huge() pmds.  They may simply choose to
1076  *             split_huge_page() instead of handling it explicitly.
1077  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
1078  * @pte_hole: if set, called for each hole at all levels
1079  * @hugetlb_entry: if set, called for each hugetlb entry
1080  *                 *Caution*: The caller must hold mmap_sem() if @hugetlb_entry
1081  *                            is used.
1082  *
1083  * (see walk_page_range for more details)
1084  */
1085 struct mm_walk {
1086         int (*pgd_entry)(pgd_t *pgd, unsigned long addr,
1087                          unsigned long next, struct mm_walk *walk);
1088         int (*pud_entry)(pud_t *pud, unsigned long addr,
1089                          unsigned long next, struct mm_walk *walk);
1090         int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
1091                          unsigned long next, struct mm_walk *walk);
1092         int (*pte_entry)(pte_t *pte, unsigned long addr,
1093                          unsigned long next, struct mm_walk *walk);
1094         int (*pte_hole)(unsigned long addr, unsigned long next,
1095                         struct mm_walk *walk);
1096         int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
1097                              unsigned long addr, unsigned long next,
1098                              struct mm_walk *walk);
1099         struct mm_struct *mm;
1100         void *private;
1101 };
1102 
1103 int walk_page_range(unsigned long addr, unsigned long end,
1104                 struct mm_walk *walk);
1105 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
1106                 unsigned long end, unsigned long floor, unsigned long ceiling);
1107 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
1108                         struct vm_area_struct *vma);
1109 void unmap_mapping_range(struct address_space *mapping,
1110                 loff_t const holebegin, loff_t const holelen, int even_cows);
1111 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
1112         unsigned long *pfn);
1113 int follow_phys(struct vm_area_struct *vma, unsigned long address,
1114                 unsigned int flags, unsigned long *prot, resource_size_t *phys);
1115 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
1116                         void *buf, int len, int write);
1117 
1118 static inline void unmap_shared_mapping_range(struct address_space *mapping,
1119                 loff_t const holebegin, loff_t const holelen)
1120 {
1121         unmap_mapping_range(mapping, holebegin, holelen, 0);
1122 }
1123 
1124 extern void truncate_pagecache(struct inode *inode, loff_t new);
1125 extern void truncate_setsize(struct inode *inode, loff_t newsize);
1126 void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end);
1127 int truncate_inode_page(struct address_space *mapping, struct page *page);
1128 int generic_error_remove_page(struct address_space *mapping, struct page *page);
1129 int invalidate_inode_page(struct page *page);
1130 
1131 #ifdef CONFIG_MMU
1132 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
1133                         unsigned long address, unsigned int flags);
1134 extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1135                             unsigned long address, unsigned int fault_flags);
1136 #else
1137 static inline int handle_mm_fault(struct mm_struct *mm,
1138                         struct vm_area_struct *vma, unsigned long address,
1139                         unsigned int flags)
1140 {
1141         /* should never happen if there's no MMU */
1142         BUG();
1143         return VM_FAULT_SIGBUS;
1144 }
1145 static inline int fixup_user_fault(struct task_struct *tsk,
1146                 struct mm_struct *mm, unsigned long address,
1147                 unsigned int fault_flags)
1148 {
1149         /* should never happen if there's no MMU */
1150         BUG();
1151         return -EFAULT;
1152 }
1153 #endif
1154 
1155 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
1156 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1157                 void *buf, int len, int write);
1158 
1159 long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1160                       unsigned long start, unsigned long nr_pages,
1161                       unsigned int foll_flags, struct page **pages,
1162                       struct vm_area_struct **vmas, int *nonblocking);
1163 long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1164                     unsigned long start, unsigned long nr_pages,
1165                     int write, int force, struct page **pages,
1166                     struct vm_area_struct **vmas);
1167 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
1168                         struct page **pages);
1169 struct kvec;
1170 int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
1171                         struct page **pages);
1172 int get_kernel_page(unsigned long start, int write, struct page **pages);
1173 struct page *get_dump_page(unsigned long addr);
1174 
1175 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
1176 extern void do_invalidatepage(struct page *page, unsigned int offset,
1177                               unsigned int length);
1178 
1179 int __set_page_dirty_nobuffers(struct page *page);
1180 int __set_page_dirty_no_writeback(struct page *page);
1181 int redirty_page_for_writepage(struct writeback_control *wbc,
1182                                 struct page *page);
1183 void account_page_dirtied(struct page *page, struct address_space *mapping);
1184 void account_page_writeback(struct page *page);
1185 int set_page_dirty(struct page *page);
1186 int set_page_dirty_lock(struct page *page);
1187 int clear_page_dirty_for_io(struct page *page);
1188 
1189 /* Is the vma a continuation of the stack vma above it? */
1190 static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
1191 {
1192         return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
1193 }
1194 
1195 static inline int stack_guard_page_start(struct vm_area_struct *vma,
1196                                              unsigned long addr)
1197 {
1198         return (vma->vm_flags & VM_GROWSDOWN) &&
1199                 (vma->vm_start == addr) &&
1200                 !vma_growsdown(vma->vm_prev, addr);
1201 }
1202 
1203 /* Is the vma a continuation of the stack vma below it? */
1204 static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
1205 {
1206         return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
1207 }
1208 
1209 static inline int stack_guard_page_end(struct vm_area_struct *vma,
1210                                            unsigned long addr)
1211 {
1212         return (vma->vm_flags & VM_GROWSUP) &&
1213                 (vma->vm_end == addr) &&
1214                 !vma_growsup(vma->vm_next, addr);
1215 }
1216 
1217 extern pid_t
1218 vm_is_stack(struct task_struct *task, struct vm_area_struct *vma, int in_group);
1219 
1220 extern unsigned long move_page_tables(struct vm_area_struct *vma,
1221                 unsigned long old_addr, struct vm_area_struct *new_vma,
1222                 unsigned long new_addr, unsigned long len,
1223                 bool need_rmap_locks);
1224 extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
1225                               unsigned long end, pgprot_t newprot,
1226                               int dirty_accountable, int prot_numa);
1227 extern int mprotect_fixup(struct vm_area_struct *vma,
1228                           struct vm_area_struct **pprev, unsigned long start,
1229                           unsigned long end, unsigned long newflags);
1230 
1231 /*
1232  * doesn't attempt to fault and will return short.
1233  */
1234 int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
1235                           struct page **pages);
1236 /*
1237  * per-process(per-mm_struct) statistics.
1238  */
1239 static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
1240 {
1241         long val = atomic_long_read(&mm->rss_stat.count[member]);
1242 
1243 #ifdef SPLIT_RSS_COUNTING
1244         /*
1245          * counter is updated in asynchronous manner and may go to minus.
1246          * But it's never be expected number for users.
1247          */
1248         if (val < 0)
1249                 val = 0;
1250 #endif
1251         return (unsigned long)val;
1252 }
1253 
1254 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
1255 {
1256         atomic_long_add(value, &mm->rss_stat.count[member]);
1257 }
1258 
1259 static inline void inc_mm_counter(struct mm_struct *mm, int member)
1260 {
1261         atomic_long_inc(&mm->rss_stat.count[member]);
1262 }
1263 
1264 static inline void dec_mm_counter(struct mm_struct *mm, int member)
1265 {
1266         atomic_long_dec(&mm->rss_stat.count[member]);
1267 }
1268 
1269 static inline unsigned long get_mm_rss(struct mm_struct *mm)
1270 {
1271         return get_mm_counter(mm, MM_FILEPAGES) +
1272                 get_mm_counter(mm, MM_ANONPAGES);
1273 }
1274 
1275 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
1276 {
1277         return max(mm->hiwater_rss, get_mm_rss(mm));
1278 }
1279 
1280 static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
1281 {
1282         return max(mm->hiwater_vm, mm->total_vm);
1283 }
1284 
1285 static inline void update_hiwater_rss(struct mm_struct *mm)
1286 {
1287         unsigned long _rss = get_mm_rss(mm);
1288 
1289         if ((mm)->hiwater_rss < _rss)
1290                 (mm)->hiwater_rss = _rss;
1291 }
1292 
1293 static inline void update_hiwater_vm(struct mm_struct *mm)
1294 {
1295         if (mm->hiwater_vm < mm->total_vm)
1296                 mm->hiwater_vm = mm->total_vm;
1297 }
1298 
1299 static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
1300                                          struct mm_struct *mm)
1301 {
1302         unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
1303 
1304         if (*maxrss < hiwater_rss)
1305                 *maxrss = hiwater_rss;
1306 }
1307 
1308 #if defined(SPLIT_RSS_COUNTING)
1309 void sync_mm_rss(struct mm_struct *mm);
1310 #else
1311 static inline void sync_mm_rss(struct mm_struct *mm)
1312 {
1313 }
1314 #endif
1315 
1316 int vma_wants_writenotify(struct vm_area_struct *vma);
1317 
1318 extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1319                                spinlock_t **ptl);
1320 static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1321                                     spinlock_t **ptl)
1322 {
1323         pte_t *ptep;
1324         __cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
1325         return ptep;
1326 }
1327 
1328 #ifdef __PAGETABLE_PUD_FOLDED
1329 static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
1330                                                 unsigned long address)
1331 {
1332         return 0;
1333 }
1334 #else
1335 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
1336 #endif
1337 
1338 #ifdef __PAGETABLE_PMD_FOLDED
1339 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
1340                                                 unsigned long address)
1341 {
1342         return 0;
1343 }
1344 #else
1345 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
1346 #endif
1347 
1348 int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
1349                 pmd_t *pmd, unsigned long address);
1350 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
1351 
1352 /*
1353  * The following ifdef needed to get the 4level-fixup.h header to work.
1354  * Remove it when 4level-fixup.h has been removed.
1355  */
1356 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
1357 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
1358 {
1359         return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
1360                 NULL: pud_offset(pgd, address);
1361 }
1362 
1363 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
1364 {
1365         return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
1366                 NULL: pmd_offset(pud, address);
1367 }
1368 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
1369 
1370 #if USE_SPLIT_PTE_PTLOCKS
1371 #if ALLOC_SPLIT_PTLOCKS
1372 void __init ptlock_cache_init(void);
1373 extern bool ptlock_alloc(struct page *page);
1374 extern void ptlock_free(struct page *page);
1375 
1376 static inline spinlock_t *ptlock_ptr(struct page *page)
1377 {
1378         return page->ptl;
1379 }
1380 #else /* ALLOC_SPLIT_PTLOCKS */
1381 static inline void ptlock_cache_init(void)
1382 {
1383 }
1384 
1385 static inline bool ptlock_alloc(struct page *page)
1386 {
1387         return true;
1388 }
1389 
1390 static inline void ptlock_free(struct page *page)
1391 {
1392 }
1393 
1394 static inline spinlock_t *ptlock_ptr(struct page *page)
1395 {
1396         return &page->ptl;
1397 }
1398 #endif /* ALLOC_SPLIT_PTLOCKS */
1399 
1400 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1401 {
1402         return ptlock_ptr(pmd_page(*pmd));
1403 }
1404 
1405 static inline bool ptlock_init(struct page *page)
1406 {
1407         /*
1408          * prep_new_page() initialize page->private (and therefore page->ptl)
1409          * with 0. Make sure nobody took it in use in between.
1410          *
1411          * It can happen if arch try to use slab for page table allocation:
1412          * slab code uses page->slab_cache and page->first_page (for tail
1413          * pages), which share storage with page->ptl.
1414          */
1415         VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
1416         if (!ptlock_alloc(page))
1417                 return false;
1418         spin_lock_init(ptlock_ptr(page));
1419         return true;
1420 }
1421 
1422 /* Reset page->mapping so free_pages_check won't complain. */
1423 static inline void pte_lock_deinit(struct page *page)
1424 {
1425         page->mapping = NULL;
1426         ptlock_free(page);
1427 }
1428 
1429 #else   /* !USE_SPLIT_PTE_PTLOCKS */
1430 /*
1431  * We use mm->page_table_lock to guard all pagetable pages of the mm.
1432  */
1433 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1434 {
1435         return &mm->page_table_lock;
1436 }
1437 static inline void ptlock_cache_init(void) {}
1438 static inline bool ptlock_init(struct page *page) { return true; }
1439 static inline void pte_lock_deinit(struct page *page) {}
1440 #endif /* USE_SPLIT_PTE_PTLOCKS */
1441 
1442 static inline void pgtable_init(void)
1443 {
1444         ptlock_cache_init();
1445         pgtable_cache_init();
1446 }
1447 
1448 static inline bool pgtable_page_ctor(struct page *page)
1449 {
1450         inc_zone_page_state(page, NR_PAGETABLE);
1451         return ptlock_init(page);
1452 }
1453 
1454 static inline void pgtable_page_dtor(struct page *page)
1455 {
1456         pte_lock_deinit(page);
1457         dec_zone_page_state(page, NR_PAGETABLE);
1458 }
1459 
1460 #define pte_offset_map_lock(mm, pmd, address, ptlp)     \
1461 ({                                                      \
1462         spinlock_t *__ptl = pte_lockptr(mm, pmd);       \
1463         pte_t *__pte = pte_offset_map(pmd, address);    \
1464         *(ptlp) = __ptl;                                \
1465         spin_lock(__ptl);                               \
1466         __pte;                                          \
1467 })
1468 
1469 #define pte_unmap_unlock(pte, ptl)      do {            \
1470         spin_unlock(ptl);                               \
1471         pte_unmap(pte);                                 \
1472 } while (0)
1473 
1474 #define pte_alloc_map(mm, vma, pmd, address)                            \
1475         ((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, vma,    \
1476                                                         pmd, address))? \
1477          NULL: pte_offset_map(pmd, address))
1478 
1479 #define pte_alloc_map_lock(mm, pmd, address, ptlp)      \
1480         ((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, NULL,   \
1481                                                         pmd, address))? \
1482                 NULL: pte_offset_map_lock(mm, pmd, address, ptlp))
1483 
1484 #define pte_alloc_kernel(pmd, address)                  \
1485         ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
1486                 NULL: pte_offset_kernel(pmd, address))
1487 
1488 #if USE_SPLIT_PMD_PTLOCKS
1489 
1490 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1491 {
1492         return ptlock_ptr(virt_to_page(pmd));
1493 }
1494 
1495 static inline bool pgtable_pmd_page_ctor(struct page *page)
1496 {
1497 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1498         page->pmd_huge_pte = NULL;
1499 #endif
1500         return ptlock_init(page);
1501 }
1502 
1503 static inline void pgtable_pmd_page_dtor(struct page *page)
1504 {
1505 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1506         VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
1507 #endif
1508         ptlock_free(page);
1509 }
1510 
1511 #define pmd_huge_pte(mm, pmd) (virt_to_page(pmd)->pmd_huge_pte)
1512 
1513 #else
1514 
1515 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1516 {
1517         return &mm->page_table_lock;
1518 }
1519 
1520 static inline bool pgtable_pmd_page_ctor(struct page *page) { return true; }
1521 static inline void pgtable_pmd_page_dtor(struct page *page) {}
1522 
1523 #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
1524 
1525 #endif
1526 
1527 static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
1528 {
1529         spinlock_t *ptl = pmd_lockptr(mm, pmd);
1530         spin_lock(ptl);
1531         return ptl;
1532 }
1533 
1534 extern void free_area_init(unsigned long * zones_size);
1535 extern void free_area_init_node(int nid, unsigned long * zones_size,
1536                 unsigned long zone_start_pfn, unsigned long *zholes_size);
1537 extern void free_initmem(void);
1538 
1539 /*
1540  * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
1541  * into the buddy system. The freed pages will be poisoned with pattern
1542  * "poison" if it's within range [0, UCHAR_MAX].
1543  * Return pages freed into the buddy system.
1544  */
1545 extern unsigned long free_reserved_area(void *start, void *end,
1546                                         int poison, char *s);
1547 
1548 #ifdef  CONFIG_HIGHMEM
1549 /*
1550  * Free a highmem page into the buddy system, adjusting totalhigh_pages
1551  * and totalram_pages.
1552  */
1553 extern void free_highmem_page(struct page *page);
1554 #endif
1555 
1556 extern void adjust_managed_page_count(struct page *page, long count);
1557 extern void mem_init_print_info(const char *str);
1558 
1559 /* Free the reserved page into the buddy system, so it gets managed. */
1560 static inline void __free_reserved_page(struct page *page)
1561 {
1562         ClearPageReserved(page);
1563         init_page_count(page);
1564         __free_page(page);
1565 }
1566 
1567 static inline void free_reserved_page(struct page *page)
1568 {
1569         __free_reserved_page(page);
1570         adjust_managed_page_count(page, 1);
1571 }
1572 
1573 static inline void mark_page_reserved(struct page *page)
1574 {
1575         SetPageReserved(page);
1576         adjust_managed_page_count(page, -1);
1577 }
1578 
1579 /*
1580  * Default method to free all the __init memory into the buddy system.
1581  * The freed pages will be poisoned with pattern "poison" if it's within
1582  * range [0, UCHAR_MAX].
1583  * Return pages freed into the buddy system.
1584  */
1585 static inline unsigned long free_initmem_default(int poison)
1586 {
1587         extern char __init_begin[], __init_end[];
1588 
1589         return free_reserved_area(&__init_begin, &__init_end,
1590                                   poison, "unused kernel");
1591 }
1592 
1593 static inline unsigned long get_num_physpages(void)
1594 {
1595         int nid;
1596         unsigned long phys_pages = 0;
1597 
1598         for_each_online_node(nid)
1599                 phys_pages += node_present_pages(nid);
1600 
1601         return phys_pages;
1602 }
1603 
1604 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1605 /*
1606  * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
1607  * zones, allocate the backing mem_map and account for memory holes in a more
1608  * architecture independent manner. This is a substitute for creating the
1609  * zone_sizes[] and zholes_size[] arrays and passing them to
1610  * free_area_init_node()
1611  *
1612  * An architecture is expected to register range of page frames backed by
1613  * physical memory with memblock_add[_node]() before calling
1614  * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
1615  * usage, an architecture is expected to do something like
1616  *
1617  * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
1618  *                                                       max_highmem_pfn};
1619  * for_each_valid_physical_page_range()
1620  *      memblock_add_node(base, size, nid)
1621  * free_area_init_nodes(max_zone_pfns);
1622  *
1623  * free_bootmem_with_active_regions() calls free_bootmem_node() for each
1624  * registered physical page range.  Similarly
1625  * sparse_memory_present_with_active_regions() calls memory_present() for
1626  * each range when SPARSEMEM is enabled.
1627  *
1628  * See mm/page_alloc.c for more information on each function exposed by
1629  * CONFIG_HAVE_MEMBLOCK_NODE_MAP.
1630  */
1631 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
1632 unsigned long node_map_pfn_alignment(void);
1633 unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
1634                                                 unsigned long end_pfn);
1635 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
1636                                                 unsigned long end_pfn);
1637 extern void get_pfn_range_for_nid(unsigned int nid,
1638                         unsigned long *start_pfn, unsigned long *end_pfn);
1639 extern unsigned long find_min_pfn_with_active_regions(void);
1640 extern void free_bootmem_with_active_regions(int nid,
1641                                                 unsigned long max_low_pfn);
1642 extern void sparse_memory_present_with_active_regions(int nid);
1643 
1644 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
1645 
1646 #if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
1647     !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
1648 static inline int __early_pfn_to_nid(unsigned long pfn)
1649 {
1650         return 0;
1651 }
1652 #else
1653 /* please see mm/page_alloc.c */
1654 extern int __meminit early_pfn_to_nid(unsigned long pfn);
1655 #ifdef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
1656 /* there is a per-arch backend function. */
1657 extern int __meminit __early_pfn_to_nid(unsigned long pfn);
1658 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
1659 #endif
1660 
1661 extern void set_dma_reserve(unsigned long new_dma_reserve);
1662 extern void memmap_init_zone(unsigned long, int, unsigned long,
1663                                 unsigned long, enum memmap_context);
1664 extern void setup_per_zone_wmarks(void);
1665 extern int __meminit init_per_zone_wmark_min(void);
1666 extern void mem_init(void);
1667 extern void __init mmap_init(void);
1668 extern void show_mem(unsigned int flags);
1669 extern void si_meminfo(struct sysinfo * val);
1670 extern void si_meminfo_node(struct sysinfo *val, int nid);
1671 
1672 extern __printf(3, 4)
1673 void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...);
1674 
1675 extern void setup_per_cpu_pageset(void);
1676 
1677 extern void zone_pcp_update(struct zone *zone);
1678 extern void zone_pcp_reset(struct zone *zone);
1679 
1680 /* page_alloc.c */
1681 extern int min_free_kbytes;
1682 
1683 /* nommu.c */
1684 extern atomic_long_t mmap_pages_allocated;
1685 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
1686 
1687 /* interval_tree.c */
1688 void vma_interval_tree_insert(struct vm_area_struct *node,
1689                               struct rb_root *root);
1690 void vma_interval_tree_insert_after(struct vm_area_struct *node,
1691                                     struct vm_area_struct *prev,
1692                                     struct rb_root *root);
1693 void vma_interval_tree_remove(struct vm_area_struct *node,
1694                               struct rb_root *root);
1695 struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root *root,
1696                                 unsigned long start, unsigned long last);
1697 struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
1698                                 unsigned long start, unsigned long last);
1699 
1700 #define vma_interval_tree_foreach(vma, root, start, last)               \
1701         for (vma = vma_interval_tree_iter_first(root, start, last);     \
1702              vma; vma = vma_interval_tree_iter_next(vma, start, last))
1703 
1704 static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
1705                                         struct list_head *list)
1706 {
1707         list_add_tail(&vma->shared.nonlinear, list);
1708 }
1709 
1710 void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
1711                                    struct rb_root *root);
1712 void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
1713                                    struct rb_root *root);
1714 struct anon_vma_chain *anon_vma_interval_tree_iter_first(
1715         struct rb_root *root, unsigned long start, unsigned long last);
1716 struct anon_vma_chain *anon_vma_interval_tree_iter_next(
1717         struct anon_vma_chain *node, unsigned long start, unsigned long last);
1718 #ifdef CONFIG_DEBUG_VM_RB
1719 void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
1720 #endif
1721 
1722 #define anon_vma_interval_tree_foreach(avc, root, start, last)           \
1723         for (avc = anon_vma_interval_tree_iter_first(root, start, last); \
1724              avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
1725 
1726 /* mmap.c */
1727 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
1728 extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
1729         unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
1730 extern struct vm_area_struct *vma_merge(struct mm_struct *,
1731         struct vm_area_struct *prev, unsigned long addr, unsigned long end,
1732         unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
1733         struct mempolicy *);
1734 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
1735 extern int split_vma(struct mm_struct *,
1736         struct vm_area_struct *, unsigned long addr, int new_below);
1737 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
1738 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
1739         struct rb_node **, struct rb_node *);
1740 extern void unlink_file_vma(struct vm_area_struct *);
1741 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
1742         unsigned long addr, unsigned long len, pgoff_t pgoff,
1743         bool *need_rmap_locks);
1744 extern void exit_mmap(struct mm_struct *);
1745 
1746 extern int mm_take_all_locks(struct mm_struct *mm);
1747 extern void mm_drop_all_locks(struct mm_struct *mm);
1748 
1749 extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
1750 extern struct file *get_mm_exe_file(struct mm_struct *mm);
1751 
1752 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
1753 extern int install_special_mapping(struct mm_struct *mm,
1754                                    unsigned long addr, unsigned long len,
1755                                    unsigned long flags, struct page **pages);
1756 
1757 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1758 
1759 extern unsigned long mmap_region(struct file *file, unsigned long addr,
1760         unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
1761 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
1762         unsigned long len, unsigned long prot, unsigned long flags,
1763         unsigned long pgoff, unsigned long *populate);
1764 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
1765 
1766 #ifdef CONFIG_MMU
1767 extern int __mm_populate(unsigned long addr, unsigned long len,
1768                          int ignore_errors);
1769 static inline void mm_populate(unsigned long addr, unsigned long len)
1770 {
1771         /* Ignore errors */
1772         (void) __mm_populate(addr, len, 1);
1773 }
1774 #else
1775 static inline void mm_populate(unsigned long addr, unsigned long len) {}
1776 #endif
1777 
1778 /* These take the mm semaphore themselves */
1779 extern unsigned long vm_brk(unsigned long, unsigned long);
1780 extern int vm_munmap(unsigned long, size_t);
1781 extern unsigned long vm_mmap(struct file *, unsigned long,
1782         unsigned long, unsigned long,
1783         unsigned long, unsigned long);
1784 
1785 struct vm_unmapped_area_info {
1786 #define VM_UNMAPPED_AREA_TOPDOWN 1
1787         unsigned long flags;
1788         unsigned long length;
1789         unsigned long low_limit;
1790         unsigned long high_limit;
1791         unsigned long align_mask;
1792         unsigned long align_offset;
1793 };
1794 
1795 extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
1796 extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
1797 
1798 /*
1799  * Search for an unmapped address range.
1800  *
1801  * We are looking for a range that:
1802  * - does not intersect with any VMA;
1803  * - is contained within the [low_limit, high_limit) interval;
1804  * - is at least the desired size.
1805  * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
1806  */
1807 static inline unsigned long
1808 vm_unmapped_area(struct vm_unmapped_area_info *info)
1809 {
1810         if (!(info->flags & VM_UNMAPPED_AREA_TOPDOWN))
1811                 return unmapped_area(info);
1812         else
1813                 return unmapped_area_topdown(info);
1814 }
1815 
1816 /* truncate.c */
1817 extern void truncate_inode_pages(struct address_space *, loff_t);
1818 extern void truncate_inode_pages_range(struct address_space *,
1819                                        loff_t lstart, loff_t lend);
1820 
1821 /* generic vm_area_ops exported for stackable file systems */
1822 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
1823 extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
1824 
1825 /* mm/page-writeback.c */
1826 int write_one_page(struct page *page, int wait);
1827 void task_dirty_inc(struct task_struct *tsk);
1828 
1829 /* readahead.c */
1830 #define VM_MAX_READAHEAD        128     /* kbytes */
1831 #define VM_MIN_READAHEAD        16      /* kbytes (includes current page) */
1832 
1833 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
1834                         pgoff_t offset, unsigned long nr_to_read);
1835 
1836 void page_cache_sync_readahead(struct address_space *mapping,
1837                                struct file_ra_state *ra,
1838                                struct file *filp,
1839                                pgoff_t offset,
1840                                unsigned long size);
1841 
1842 void page_cache_async_readahead(struct address_space *mapping,
1843                                 struct file_ra_state *ra,
1844                                 struct file *filp,
1845                                 struct page *pg,
1846                                 pgoff_t offset,
1847                                 unsigned long size);
1848 
1849 unsigned long max_sane_readahead(unsigned long nr);
1850 unsigned long ra_submit(struct file_ra_state *ra,
1851                         struct address_space *mapping,
1852                         struct file *filp);
1853 
1854 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
1855 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
1856 
1857 /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
1858 extern int expand_downwards(struct vm_area_struct *vma,
1859                 unsigned long address);
1860 #if VM_GROWSUP
1861 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
1862 #else
1863   #define expand_upwards(vma, address) do { } while (0)
1864 #endif
1865 
1866 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
1867 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
1868 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
1869                                              struct vm_area_struct **pprev);
1870 
1871 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
1872    NULL if none.  Assume start_addr < end_addr. */
1873 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
1874 {
1875         struct vm_area_struct * vma = find_vma(mm,start_addr);
1876 
1877         if (vma && end_addr <= vma->vm_start)
1878                 vma = NULL;
1879         return vma;
1880 }
1881 
1882 static inline unsigned long vma_pages(struct vm_area_struct *vma)
1883 {
1884         return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
1885 }
1886 
1887 /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
1888 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
1889                                 unsigned long vm_start, unsigned long vm_end)
1890 {
1891         struct vm_area_struct *vma = find_vma(mm, vm_start);
1892 
1893         if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
1894                 vma = NULL;
1895 
1896         return vma;
1897 }
1898 
1899 #ifdef CONFIG_MMU
1900 pgprot_t vm_get_page_prot(unsigned long vm_flags);
1901 #else
1902 static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
1903 {
1904         return __pgprot(0);
1905 }
1906 #endif
1907 
1908 #ifdef CONFIG_NUMA_BALANCING
1909 unsigned long change_prot_numa(struct vm_area_struct *vma,
1910                         unsigned long start, unsigned long end);
1911 #endif
1912 
1913 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
1914 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
1915                         unsigned long pfn, unsigned long size, pgprot_t);
1916 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
1917 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1918                         unsigned long pfn);
1919 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1920                         unsigned long pfn);
1921 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
1922 
1923 
1924 struct page *follow_page_mask(struct vm_area_struct *vma,
1925                               unsigned long address, unsigned int foll_flags,
1926                               unsigned int *page_mask);
1927 
1928 static inline struct page *follow_page(struct vm_area_struct *vma,
1929                 unsigned long address, unsigned int foll_flags)
1930 {
1931         unsigned int unused_page_mask;
1932         return follow_page_mask(vma, address, foll_flags, &unused_page_mask);
1933 }
1934 
1935 #define FOLL_WRITE      0x01    /* check pte is writable */
1936 #define FOLL_TOUCH      0x02    /* mark page accessed */
1937 #define FOLL_GET        0x04    /* do get_page on page */
1938 #define FOLL_DUMP       0x08    /* give error on hole if it would be zero */
1939 #define FOLL_FORCE      0x10    /* get_user_pages read/write w/o permission */
1940 #define FOLL_NOWAIT     0x20    /* if a disk transfer is needed, start the IO
1941                                  * and return without waiting upon it */
1942 #define FOLL_MLOCK      0x40    /* mark page as mlocked */
1943 #define FOLL_SPLIT      0x80    /* don't return transhuge pages, split them */
1944 #define FOLL_HWPOISON   0x100   /* check page is hwpoisoned */
1945 #define FOLL_NUMA       0x200   /* force NUMA hinting page fault */
1946 #define FOLL_MIGRATION  0x400   /* wait for page to replace migration entry */
1947 
1948 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
1949                         void *data);
1950 extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
1951                                unsigned long size, pte_fn_t fn, void *data);
1952 
1953 #ifdef CONFIG_PROC_FS
1954 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
1955 #else
1956 static inline void vm_stat_account(struct mm_struct *mm,
1957                         unsigned long flags, struct file *file, long pages)
1958 {
1959         mm->total_vm += pages;
1960 }
1961 #endif /* CONFIG_PROC_FS */
1962 
1963 #ifdef CONFIG_DEBUG_PAGEALLOC
1964 extern void kernel_map_pages(struct page *page, int numpages, int enable);
1965 #ifdef CONFIG_HIBERNATION
1966 extern bool kernel_page_present(struct page *page);
1967 #endif /* CONFIG_HIBERNATION */
1968 #else
1969 static inline void
1970 kernel_map_pages(struct page *page, int numpages, int enable) {}
1971 #ifdef CONFIG_HIBERNATION
1972 static inline bool kernel_page_present(struct page *page) { return true; }
1973 #endif /* CONFIG_HIBERNATION */
1974 #endif
1975 
1976 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
1977 #ifdef  __HAVE_ARCH_GATE_AREA
1978 int in_gate_area_no_mm(unsigned long addr);
1979 int in_gate_area(struct mm_struct *mm, unsigned long addr);
1980 #else
1981 int in_gate_area_no_mm(unsigned long addr);
1982 #define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
1983 #endif  /* __HAVE_ARCH_GATE_AREA */
1984 
1985 #ifdef CONFIG_SYSCTL
1986 extern int sysctl_drop_caches;
1987 int drop_caches_sysctl_handler(struct ctl_table *, int,
1988                                         void __user *, size_t *, loff_t *);
1989 #endif
1990 
1991 unsigned long shrink_slab(struct shrink_control *shrink,
1992                           unsigned long nr_pages_scanned,
1993                           unsigned long lru_pages);
1994 
1995 #ifndef CONFIG_MMU
1996 #define randomize_va_space 0
1997 #else
1998 extern int randomize_va_space;
1999 #endif
2000 
2001 const char * arch_vma_name(struct vm_area_struct *vma);
2002 void print_vma_addr(char *prefix, unsigned long rip);
2003 
2004 void sparse_mem_maps_populate_node(struct page **map_map,
2005                                    unsigned long pnum_begin,
2006                                    unsigned long pnum_end,
2007                                    unsigned long map_count,
2008                                    int nodeid);
2009 
2010 struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
2011 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
2012 pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
2013 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
2014 pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
2015 void *vmemmap_alloc_block(unsigned long size, int node);
2016 void *vmemmap_alloc_block_buf(unsigned long size, int node);
2017 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
2018 int vmemmap_populate_basepages(unsigned long start, unsigned long end,
2019                                int node);
2020 int vmemmap_populate(unsigned long start, unsigned long end, int node);
2021 void vmemmap_populate_print_last(void);
2022 #ifdef CONFIG_MEMORY_HOTPLUG
2023 void vmemmap_free(unsigned long start, unsigned long end);
2024 #endif
2025 void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
2026                                   unsigned long size);
2027 
2028 enum mf_flags {
2029         MF_COUNT_INCREASED = 1 << 0,
2030         MF_ACTION_REQUIRED = 1 << 1,
2031         MF_MUST_KILL = 1 << 2,
2032         MF_SOFT_OFFLINE = 1 << 3,
2033 };
2034 extern int memory_failure(unsigned long pfn, int trapno, int flags);
2035 extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
2036 extern int unpoison_memory(unsigned long pfn);
2037 extern int sysctl_memory_failure_early_kill;
2038 extern int sysctl_memory_failure_recovery;
2039 extern void shake_page(struct page *p, int access);
2040 extern atomic_long_t num_poisoned_pages;
2041 extern int soft_offline_page(struct page *page, int flags);
2042 
2043 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
2044 extern void clear_huge_page(struct page *page,
2045                             unsigned long addr,
2046                             unsigned int pages_per_huge_page);
2047 extern void copy_user_huge_page(struct page *dst, struct page *src,
2048                                 unsigned long addr, struct vm_area_struct *vma,
2049                                 unsigned int pages_per_huge_page);
2050 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
2051 
2052 #ifdef CONFIG_DEBUG_PAGEALLOC
2053 extern unsigned int _debug_guardpage_minorder;
2054 
2055 static inline unsigned int debug_guardpage_minorder(void)
2056 {
2057         return _debug_guardpage_minorder;
2058 }
2059 
2060 static inline bool page_is_guard(struct page *page)
2061 {
2062         return test_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
2063 }
2064 #else
2065 static inline unsigned int debug_guardpage_minorder(void) { return 0; }
2066 static inline bool page_is_guard(struct page *page) { return false; }
2067 #endif /* CONFIG_DEBUG_PAGEALLOC */
2068 
2069 #if MAX_NUMNODES > 1
2070 void __init setup_nr_node_ids(void);
2071 #else
2072 static inline void setup_nr_node_ids(void) {}
2073 #endif
2074 
2075 #endif /* __KERNEL__ */
2076 #endif /* _LINUX_MM_H */
2077 

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