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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/percpu-refcount.h>
 20 #include <linux/bit_spinlock.h>
 21 #include <linux/shrinker.h>
 22 #include <linux/resource.h>
 23 #include <linux/page_ext.h>
 24 #include <linux/err.h>
 25 #include <linux/page_ref.h>
 26 
 27 struct mempolicy;
 28 struct anon_vma;
 29 struct anon_vma_chain;
 30 struct file_ra_state;
 31 struct user_struct;
 32 struct writeback_control;
 33 struct bdi_writeback;
 34 
 35 #ifndef CONFIG_NEED_MULTIPLE_NODES      /* Don't use mapnrs, do it properly */
 36 extern unsigned long max_mapnr;
 37 
 38 static inline void set_max_mapnr(unsigned long limit)
 39 {
 40         max_mapnr = limit;
 41 }
 42 #else
 43 static inline void set_max_mapnr(unsigned long limit) { }
 44 #endif
 45 
 46 extern unsigned long totalram_pages;
 47 extern void * high_memory;
 48 extern int page_cluster;
 49 
 50 #ifdef CONFIG_SYSCTL
 51 extern int sysctl_legacy_va_layout;
 52 #else
 53 #define sysctl_legacy_va_layout 0
 54 #endif
 55 
 56 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
 57 extern const int mmap_rnd_bits_min;
 58 extern const int mmap_rnd_bits_max;
 59 extern int mmap_rnd_bits __read_mostly;
 60 #endif
 61 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
 62 extern const int mmap_rnd_compat_bits_min;
 63 extern const int mmap_rnd_compat_bits_max;
 64 extern int mmap_rnd_compat_bits __read_mostly;
 65 #endif
 66 
 67 #include <asm/page.h>
 68 #include <asm/pgtable.h>
 69 #include <asm/processor.h>
 70 
 71 #ifndef __pa_symbol
 72 #define __pa_symbol(x)  __pa(RELOC_HIDE((unsigned long)(x), 0))
 73 #endif
 74 
 75 /*
 76  * To prevent common memory management code establishing
 77  * a zero page mapping on a read fault.
 78  * This macro should be defined within <asm/pgtable.h>.
 79  * s390 does this to prevent multiplexing of hardware bits
 80  * related to the physical page in case of virtualization.
 81  */
 82 #ifndef mm_forbids_zeropage
 83 #define mm_forbids_zeropage(X)  (0)
 84 #endif
 85 
 86 /*
 87  * Default maximum number of active map areas, this limits the number of vmas
 88  * per mm struct. Users can overwrite this number by sysctl but there is a
 89  * problem.
 90  *
 91  * When a program's coredump is generated as ELF format, a section is created
 92  * per a vma. In ELF, the number of sections is represented in unsigned short.
 93  * This means the number of sections should be smaller than 65535 at coredump.
 94  * Because the kernel adds some informative sections to a image of program at
 95  * generating coredump, we need some margin. The number of extra sections is
 96  * 1-3 now and depends on arch. We use "5" as safe margin, here.
 97  *
 98  * ELF extended numbering allows more than 65535 sections, so 16-bit bound is
 99  * not a hard limit any more. Although some userspace tools can be surprised by
100  * that.
101  */
102 #define MAPCOUNT_ELF_CORE_MARGIN        (5)
103 #define DEFAULT_MAX_MAP_COUNT   (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)
104 
105 extern int sysctl_max_map_count;
106 
107 extern unsigned long sysctl_user_reserve_kbytes;
108 extern unsigned long sysctl_admin_reserve_kbytes;
109 
110 extern int sysctl_overcommit_memory;
111 extern int sysctl_overcommit_ratio;
112 extern unsigned long sysctl_overcommit_kbytes;
113 
114 extern int overcommit_ratio_handler(struct ctl_table *, int, void __user *,
115                                     size_t *, loff_t *);
116 extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
117                                     size_t *, loff_t *);
118 
119 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
120 
121 /* to align the pointer to the (next) page boundary */
122 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
123 
124 /* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
125 #define PAGE_ALIGNED(addr)      IS_ALIGNED((unsigned long)addr, PAGE_SIZE)
126 
127 /*
128  * Linux kernel virtual memory manager primitives.
129  * The idea being to have a "virtual" mm in the same way
130  * we have a virtual fs - giving a cleaner interface to the
131  * mm details, and allowing different kinds of memory mappings
132  * (from shared memory to executable loading to arbitrary
133  * mmap() functions).
134  */
135 
136 extern struct kmem_cache *vm_area_cachep;
137 
138 #ifndef CONFIG_MMU
139 extern struct rb_root nommu_region_tree;
140 extern struct rw_semaphore nommu_region_sem;
141 
142 extern unsigned int kobjsize(const void *objp);
143 #endif
144 
145 /*
146  * vm_flags in vm_area_struct, see mm_types.h.
147  * When changing, update also include/trace/events/mmflags.h
148  */
149 #define VM_NONE         0x00000000
150 
151 #define VM_READ         0x00000001      /* currently active flags */
152 #define VM_WRITE        0x00000002
153 #define VM_EXEC         0x00000004
154 #define VM_SHARED       0x00000008
155 
156 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
157 #define VM_MAYREAD      0x00000010      /* limits for mprotect() etc */
158 #define VM_MAYWRITE     0x00000020
159 #define VM_MAYEXEC      0x00000040
160 #define VM_MAYSHARE     0x00000080
161 
162 #define VM_GROWSDOWN    0x00000100      /* general info on the segment */
163 #define VM_UFFD_MISSING 0x00000200      /* missing pages tracking */
164 #define VM_PFNMAP       0x00000400      /* Page-ranges managed without "struct page", just pure PFN */
165 #define VM_DENYWRITE    0x00000800      /* ETXTBSY on write attempts.. */
166 #define VM_UFFD_WP      0x00001000      /* wrprotect pages tracking */
167 
168 #define VM_LOCKED       0x00002000
169 #define VM_IO           0x00004000      /* Memory mapped I/O or similar */
170 
171                                         /* Used by sys_madvise() */
172 #define VM_SEQ_READ     0x00008000      /* App will access data sequentially */
173 #define VM_RAND_READ    0x00010000      /* App will not benefit from clustered reads */
174 
175 #define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
176 #define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
177 #define VM_LOCKONFAULT  0x00080000      /* Lock the pages covered when they are faulted in */
178 #define VM_ACCOUNT      0x00100000      /* Is a VM accounted object */
179 #define VM_NORESERVE    0x00200000      /* should the VM suppress accounting */
180 #define VM_HUGETLB      0x00400000      /* Huge TLB Page VM */
181 #define VM_ARCH_1       0x01000000      /* Architecture-specific flag */
182 #define VM_ARCH_2       0x02000000
183 #define VM_DONTDUMP     0x04000000      /* Do not include in the core dump */
184 
185 #ifdef CONFIG_MEM_SOFT_DIRTY
186 # define VM_SOFTDIRTY   0x08000000      /* Not soft dirty clean area */
187 #else
188 # define VM_SOFTDIRTY   0
189 #endif
190 
191 #define VM_MIXEDMAP     0x10000000      /* Can contain "struct page" and pure PFN pages */
192 #define VM_HUGEPAGE     0x20000000      /* MADV_HUGEPAGE marked this vma */
193 #define VM_NOHUGEPAGE   0x40000000      /* MADV_NOHUGEPAGE marked this vma */
194 #define VM_MERGEABLE    0x80000000      /* KSM may merge identical pages */
195 
196 #ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
197 #define VM_HIGH_ARCH_BIT_0      32      /* bit only usable on 64-bit architectures */
198 #define VM_HIGH_ARCH_BIT_1      33      /* bit only usable on 64-bit architectures */
199 #define VM_HIGH_ARCH_BIT_2      34      /* bit only usable on 64-bit architectures */
200 #define VM_HIGH_ARCH_BIT_3      35      /* bit only usable on 64-bit architectures */
201 #define VM_HIGH_ARCH_0  BIT(VM_HIGH_ARCH_BIT_0)
202 #define VM_HIGH_ARCH_1  BIT(VM_HIGH_ARCH_BIT_1)
203 #define VM_HIGH_ARCH_2  BIT(VM_HIGH_ARCH_BIT_2)
204 #define VM_HIGH_ARCH_3  BIT(VM_HIGH_ARCH_BIT_3)
205 #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
206 
207 #if defined(CONFIG_X86)
208 # define VM_PAT         VM_ARCH_1       /* PAT reserves whole VMA at once (x86) */
209 #if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)
210 # define VM_PKEY_SHIFT  VM_HIGH_ARCH_BIT_0
211 # define VM_PKEY_BIT0   VM_HIGH_ARCH_0  /* A protection key is a 4-bit value */
212 # define VM_PKEY_BIT1   VM_HIGH_ARCH_1
213 # define VM_PKEY_BIT2   VM_HIGH_ARCH_2
214 # define VM_PKEY_BIT3   VM_HIGH_ARCH_3
215 #endif
216 #elif defined(CONFIG_PPC)
217 # define VM_SAO         VM_ARCH_1       /* Strong Access Ordering (powerpc) */
218 #elif defined(CONFIG_PARISC)
219 # define VM_GROWSUP     VM_ARCH_1
220 #elif defined(CONFIG_METAG)
221 # define VM_GROWSUP     VM_ARCH_1
222 #elif defined(CONFIG_IA64)
223 # define VM_GROWSUP     VM_ARCH_1
224 #elif !defined(CONFIG_MMU)
225 # define VM_MAPPED_COPY VM_ARCH_1       /* T if mapped copy of data (nommu mmap) */
226 #endif
227 
228 #if defined(CONFIG_X86)
229 /* MPX specific bounds table or bounds directory */
230 # define VM_MPX         VM_ARCH_2
231 #endif
232 
233 #ifndef VM_GROWSUP
234 # define VM_GROWSUP     VM_NONE
235 #endif
236 
237 /* Bits set in the VMA until the stack is in its final location */
238 #define VM_STACK_INCOMPLETE_SETUP       (VM_RAND_READ | VM_SEQ_READ)
239 
240 #ifndef VM_STACK_DEFAULT_FLAGS          /* arch can override this */
241 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
242 #endif
243 
244 #ifdef CONFIG_STACK_GROWSUP
245 #define VM_STACK        VM_GROWSUP
246 #else
247 #define VM_STACK        VM_GROWSDOWN
248 #endif
249 
250 #define VM_STACK_FLAGS  (VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
251 
252 /*
253  * Special vmas that are non-mergable, non-mlock()able.
254  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
255  */
256 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
257 
258 /* This mask defines which mm->def_flags a process can inherit its parent */
259 #define VM_INIT_DEF_MASK        VM_NOHUGEPAGE
260 
261 /* This mask is used to clear all the VMA flags used by mlock */
262 #define VM_LOCKED_CLEAR_MASK    (~(VM_LOCKED | VM_LOCKONFAULT))
263 
264 /*
265  * mapping from the currently active vm_flags protection bits (the
266  * low four bits) to a page protection mask..
267  */
268 extern pgprot_t protection_map[16];
269 
270 #define FAULT_FLAG_WRITE        0x01    /* Fault was a write access */
271 #define FAULT_FLAG_MKWRITE      0x02    /* Fault was mkwrite of existing pte */
272 #define FAULT_FLAG_ALLOW_RETRY  0x04    /* Retry fault if blocking */
273 #define FAULT_FLAG_RETRY_NOWAIT 0x08    /* Don't drop mmap_sem and wait when retrying */
274 #define FAULT_FLAG_KILLABLE     0x10    /* The fault task is in SIGKILL killable region */
275 #define FAULT_FLAG_TRIED        0x20    /* Second try */
276 #define FAULT_FLAG_USER         0x40    /* The fault originated in userspace */
277 #define FAULT_FLAG_REMOTE       0x80    /* faulting for non current tsk/mm */
278 #define FAULT_FLAG_INSTRUCTION  0x100   /* The fault was during an instruction fetch */
279 
280 /*
281  * vm_fault is filled by the the pagefault handler and passed to the vma's
282  * ->fault function. The vma's ->fault is responsible for returning a bitmask
283  * of VM_FAULT_xxx flags that give details about how the fault was handled.
284  *
285  * MM layer fills up gfp_mask for page allocations but fault handler might
286  * alter it if its implementation requires a different allocation context.
287  *
288  * pgoff should be used in favour of virtual_address, if possible.
289  */
290 struct vm_fault {
291         unsigned int flags;             /* FAULT_FLAG_xxx flags */
292         gfp_t gfp_mask;                 /* gfp mask to be used for allocations */
293         pgoff_t pgoff;                  /* Logical page offset based on vma */
294         void __user *virtual_address;   /* Faulting virtual address */
295 
296         struct page *cow_page;          /* Handler may choose to COW */
297         struct page *page;              /* ->fault handlers should return a
298                                          * page here, unless VM_FAULT_NOPAGE
299                                          * is set (which is also implied by
300                                          * VM_FAULT_ERROR).
301                                          */
302         /* for ->map_pages() only */
303         pgoff_t max_pgoff;              /* map pages for offset from pgoff till
304                                          * max_pgoff inclusive */
305         pte_t *pte;                     /* pte entry associated with ->pgoff */
306 };
307 
308 /*
309  * These are the virtual MM functions - opening of an area, closing and
310  * unmapping it (needed to keep files on disk up-to-date etc), pointer
311  * to the functions called when a no-page or a wp-page exception occurs. 
312  */
313 struct vm_operations_struct {
314         void (*open)(struct vm_area_struct * area);
315         void (*close)(struct vm_area_struct * area);
316         int (*mremap)(struct vm_area_struct * area);
317         int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
318         int (*pmd_fault)(struct vm_area_struct *, unsigned long address,
319                                                 pmd_t *, unsigned int flags);
320         void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);
321 
322         /* notification that a previously read-only page is about to become
323          * writable, if an error is returned it will cause a SIGBUS */
324         int (*page_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
325 
326         /* same as page_mkwrite when using VM_PFNMAP|VM_MIXEDMAP */
327         int (*pfn_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
328 
329         /* called by access_process_vm when get_user_pages() fails, typically
330          * for use by special VMAs that can switch between memory and hardware
331          */
332         int (*access)(struct vm_area_struct *vma, unsigned long addr,
333                       void *buf, int len, int write);
334 
335         /* Called by the /proc/PID/maps code to ask the vma whether it
336          * has a special name.  Returning non-NULL will also cause this
337          * vma to be dumped unconditionally. */
338         const char *(*name)(struct vm_area_struct *vma);
339 
340 #ifdef CONFIG_NUMA
341         /*
342          * set_policy() op must add a reference to any non-NULL @new mempolicy
343          * to hold the policy upon return.  Caller should pass NULL @new to
344          * remove a policy and fall back to surrounding context--i.e. do not
345          * install a MPOL_DEFAULT policy, nor the task or system default
346          * mempolicy.
347          */
348         int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
349 
350         /*
351          * get_policy() op must add reference [mpol_get()] to any policy at
352          * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
353          * in mm/mempolicy.c will do this automatically.
354          * get_policy() must NOT add a ref if the policy at (vma,addr) is not
355          * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
356          * If no [shared/vma] mempolicy exists at the addr, get_policy() op
357          * must return NULL--i.e., do not "fallback" to task or system default
358          * policy.
359          */
360         struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
361                                         unsigned long addr);
362 #endif
363         /*
364          * Called by vm_normal_page() for special PTEs to find the
365          * page for @addr.  This is useful if the default behavior
366          * (using pte_page()) would not find the correct page.
367          */
368         struct page *(*find_special_page)(struct vm_area_struct *vma,
369                                           unsigned long addr);
370 };
371 
372 struct mmu_gather;
373 struct inode;
374 
375 #define page_private(page)              ((page)->private)
376 #define set_page_private(page, v)       ((page)->private = (v))
377 
378 #if !defined(__HAVE_ARCH_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
379 static inline int pmd_devmap(pmd_t pmd)
380 {
381         return 0;
382 }
383 #endif
384 
385 /*
386  * FIXME: take this include out, include page-flags.h in
387  * files which need it (119 of them)
388  */
389 #include <linux/page-flags.h>
390 #include <linux/huge_mm.h>
391 
392 /*
393  * Methods to modify the page usage count.
394  *
395  * What counts for a page usage:
396  * - cache mapping   (page->mapping)
397  * - private data    (page->private)
398  * - page mapped in a task's page tables, each mapping
399  *   is counted separately
400  *
401  * Also, many kernel routines increase the page count before a critical
402  * routine so they can be sure the page doesn't go away from under them.
403  */
404 
405 /*
406  * Drop a ref, return true if the refcount fell to zero (the page has no users)
407  */
408 static inline int put_page_testzero(struct page *page)
409 {
410         VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
411         return page_ref_dec_and_test(page);
412 }
413 
414 /*
415  * Try to grab a ref unless the page has a refcount of zero, return false if
416  * that is the case.
417  * This can be called when MMU is off so it must not access
418  * any of the virtual mappings.
419  */
420 static inline int get_page_unless_zero(struct page *page)
421 {
422         return page_ref_add_unless(page, 1, 0);
423 }
424 
425 extern int page_is_ram(unsigned long pfn);
426 
427 enum {
428         REGION_INTERSECTS,
429         REGION_DISJOINT,
430         REGION_MIXED,
431 };
432 
433 int region_intersects(resource_size_t offset, size_t size, unsigned long flags,
434                       unsigned long desc);
435 
436 /* Support for virtually mapped pages */
437 struct page *vmalloc_to_page(const void *addr);
438 unsigned long vmalloc_to_pfn(const void *addr);
439 
440 /*
441  * Determine if an address is within the vmalloc range
442  *
443  * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
444  * is no special casing required.
445  */
446 static inline int is_vmalloc_addr(const void *x)
447 {
448 #ifdef CONFIG_MMU
449         unsigned long addr = (unsigned long)x;
450 
451         return addr >= VMALLOC_START && addr < VMALLOC_END;
452 #else
453         return 0;
454 #endif
455 }
456 #ifdef CONFIG_MMU
457 extern int is_vmalloc_or_module_addr(const void *x);
458 #else
459 static inline int is_vmalloc_or_module_addr(const void *x)
460 {
461         return 0;
462 }
463 #endif
464 
465 extern void kvfree(const void *addr);
466 
467 static inline atomic_t *compound_mapcount_ptr(struct page *page)
468 {
469         return &page[1].compound_mapcount;
470 }
471 
472 static inline int compound_mapcount(struct page *page)
473 {
474         if (!PageCompound(page))
475                 return 0;
476         page = compound_head(page);
477         return atomic_read(compound_mapcount_ptr(page)) + 1;
478 }
479 
480 /*
481  * The atomic page->_mapcount, starts from -1: so that transitions
482  * both from it and to it can be tracked, using atomic_inc_and_test
483  * and atomic_add_negative(-1).
484  */
485 static inline void page_mapcount_reset(struct page *page)
486 {
487         atomic_set(&(page)->_mapcount, -1);
488 }
489 
490 int __page_mapcount(struct page *page);
491 
492 static inline int page_mapcount(struct page *page)
493 {
494         VM_BUG_ON_PAGE(PageSlab(page), page);
495 
496         if (unlikely(PageCompound(page)))
497                 return __page_mapcount(page);
498         return atomic_read(&page->_mapcount) + 1;
499 }
500 
501 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
502 int total_mapcount(struct page *page);
503 int page_trans_huge_mapcount(struct page *page, int *total_mapcount);
504 #else
505 static inline int total_mapcount(struct page *page)
506 {
507         return page_mapcount(page);
508 }
509 static inline int page_trans_huge_mapcount(struct page *page,
510                                            int *total_mapcount)
511 {
512         int mapcount = page_mapcount(page);
513         if (total_mapcount)
514                 *total_mapcount = mapcount;
515         return mapcount;
516 }
517 #endif
518 
519 static inline struct page *virt_to_head_page(const void *x)
520 {
521         struct page *page = virt_to_page(x);
522 
523         return compound_head(page);
524 }
525 
526 void __put_page(struct page *page);
527 
528 void put_pages_list(struct list_head *pages);
529 
530 void split_page(struct page *page, unsigned int order);
531 int split_free_page(struct page *page);
532 
533 /*
534  * Compound pages have a destructor function.  Provide a
535  * prototype for that function and accessor functions.
536  * These are _only_ valid on the head of a compound page.
537  */
538 typedef void compound_page_dtor(struct page *);
539 
540 /* Keep the enum in sync with compound_page_dtors array in mm/page_alloc.c */
541 enum compound_dtor_id {
542         NULL_COMPOUND_DTOR,
543         COMPOUND_PAGE_DTOR,
544 #ifdef CONFIG_HUGETLB_PAGE
545         HUGETLB_PAGE_DTOR,
546 #endif
547 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
548         TRANSHUGE_PAGE_DTOR,
549 #endif
550         NR_COMPOUND_DTORS,
551 };
552 extern compound_page_dtor * const compound_page_dtors[];
553 
554 static inline void set_compound_page_dtor(struct page *page,
555                 enum compound_dtor_id compound_dtor)
556 {
557         VM_BUG_ON_PAGE(compound_dtor >= NR_COMPOUND_DTORS, page);
558         page[1].compound_dtor = compound_dtor;
559 }
560 
561 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
562 {
563         VM_BUG_ON_PAGE(page[1].compound_dtor >= NR_COMPOUND_DTORS, page);
564         return compound_page_dtors[page[1].compound_dtor];
565 }
566 
567 static inline unsigned int compound_order(struct page *page)
568 {
569         if (!PageHead(page))
570                 return 0;
571         return page[1].compound_order;
572 }
573 
574 static inline void set_compound_order(struct page *page, unsigned int order)
575 {
576         page[1].compound_order = order;
577 }
578 
579 void free_compound_page(struct page *page);
580 
581 #ifdef CONFIG_MMU
582 /*
583  * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
584  * servicing faults for write access.  In the normal case, do always want
585  * pte_mkwrite.  But get_user_pages can cause write faults for mappings
586  * that do not have writing enabled, when used by access_process_vm.
587  */
588 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
589 {
590         if (likely(vma->vm_flags & VM_WRITE))
591                 pte = pte_mkwrite(pte);
592         return pte;
593 }
594 
595 void do_set_pte(struct vm_area_struct *vma, unsigned long address,
596                 struct page *page, pte_t *pte, bool write, bool anon);
597 #endif
598 
599 /*
600  * Multiple processes may "see" the same page. E.g. for untouched
601  * mappings of /dev/null, all processes see the same page full of
602  * zeroes, and text pages of executables and shared libraries have
603  * only one copy in memory, at most, normally.
604  *
605  * For the non-reserved pages, page_count(page) denotes a reference count.
606  *   page_count() == 0 means the page is free. page->lru is then used for
607  *   freelist management in the buddy allocator.
608  *   page_count() > 0  means the page has been allocated.
609  *
610  * Pages are allocated by the slab allocator in order to provide memory
611  * to kmalloc and kmem_cache_alloc. In this case, the management of the
612  * page, and the fields in 'struct page' are the responsibility of mm/slab.c
613  * unless a particular usage is carefully commented. (the responsibility of
614  * freeing the kmalloc memory is the caller's, of course).
615  *
616  * A page may be used by anyone else who does a __get_free_page().
617  * In this case, page_count still tracks the references, and should only
618  * be used through the normal accessor functions. The top bits of page->flags
619  * and page->virtual store page management information, but all other fields
620  * are unused and could be used privately, carefully. The management of this
621  * page is the responsibility of the one who allocated it, and those who have
622  * subsequently been given references to it.
623  *
624  * The other pages (we may call them "pagecache pages") are completely
625  * managed by the Linux memory manager: I/O, buffers, swapping etc.
626  * The following discussion applies only to them.
627  *
628  * A pagecache page contains an opaque `private' member, which belongs to the
629  * page's address_space. Usually, this is the address of a circular list of
630  * the page's disk buffers. PG_private must be set to tell the VM to call
631  * into the filesystem to release these pages.
632  *
633  * A page may belong to an inode's memory mapping. In this case, page->mapping
634  * is the pointer to the inode, and page->index is the file offset of the page,
635  * in units of PAGE_SIZE.
636  *
637  * If pagecache pages are not associated with an inode, they are said to be
638  * anonymous pages. These may become associated with the swapcache, and in that
639  * case PG_swapcache is set, and page->private is an offset into the swapcache.
640  *
641  * In either case (swapcache or inode backed), the pagecache itself holds one
642  * reference to the page. Setting PG_private should also increment the
643  * refcount. The each user mapping also has a reference to the page.
644  *
645  * The pagecache pages are stored in a per-mapping radix tree, which is
646  * rooted at mapping->page_tree, and indexed by offset.
647  * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
648  * lists, we instead now tag pages as dirty/writeback in the radix tree.
649  *
650  * All pagecache pages may be subject to I/O:
651  * - inode pages may need to be read from disk,
652  * - inode pages which have been modified and are MAP_SHARED may need
653  *   to be written back to the inode on disk,
654  * - anonymous pages (including MAP_PRIVATE file mappings) which have been
655  *   modified may need to be swapped out to swap space and (later) to be read
656  *   back into memory.
657  */
658 
659 /*
660  * The zone field is never updated after free_area_init_core()
661  * sets it, so none of the operations on it need to be atomic.
662  */
663 
664 /* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
665 #define SECTIONS_PGOFF          ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
666 #define NODES_PGOFF             (SECTIONS_PGOFF - NODES_WIDTH)
667 #define ZONES_PGOFF             (NODES_PGOFF - ZONES_WIDTH)
668 #define LAST_CPUPID_PGOFF       (ZONES_PGOFF - LAST_CPUPID_WIDTH)
669 
670 /*
671  * Define the bit shifts to access each section.  For non-existent
672  * sections we define the shift as 0; that plus a 0 mask ensures
673  * the compiler will optimise away reference to them.
674  */
675 #define SECTIONS_PGSHIFT        (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
676 #define NODES_PGSHIFT           (NODES_PGOFF * (NODES_WIDTH != 0))
677 #define ZONES_PGSHIFT           (ZONES_PGOFF * (ZONES_WIDTH != 0))
678 #define LAST_CPUPID_PGSHIFT     (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
679 
680 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
681 #ifdef NODE_NOT_IN_PAGE_FLAGS
682 #define ZONEID_SHIFT            (SECTIONS_SHIFT + ZONES_SHIFT)
683 #define ZONEID_PGOFF            ((SECTIONS_PGOFF < ZONES_PGOFF)? \
684                                                 SECTIONS_PGOFF : ZONES_PGOFF)
685 #else
686 #define ZONEID_SHIFT            (NODES_SHIFT + ZONES_SHIFT)
687 #define ZONEID_PGOFF            ((NODES_PGOFF < ZONES_PGOFF)? \
688                                                 NODES_PGOFF : ZONES_PGOFF)
689 #endif
690 
691 #define ZONEID_PGSHIFT          (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
692 
693 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
694 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
695 #endif
696 
697 #define ZONES_MASK              ((1UL << ZONES_WIDTH) - 1)
698 #define NODES_MASK              ((1UL << NODES_WIDTH) - 1)
699 #define SECTIONS_MASK           ((1UL << SECTIONS_WIDTH) - 1)
700 #define LAST_CPUPID_MASK        ((1UL << LAST_CPUPID_SHIFT) - 1)
701 #define ZONEID_MASK             ((1UL << ZONEID_SHIFT) - 1)
702 
703 static inline enum zone_type page_zonenum(const struct page *page)
704 {
705         return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
706 }
707 
708 #ifdef CONFIG_ZONE_DEVICE
709 void get_zone_device_page(struct page *page);
710 void put_zone_device_page(struct page *page);
711 static inline bool is_zone_device_page(const struct page *page)
712 {
713         return page_zonenum(page) == ZONE_DEVICE;
714 }
715 #else
716 static inline void get_zone_device_page(struct page *page)
717 {
718 }
719 static inline void put_zone_device_page(struct page *page)
720 {
721 }
722 static inline bool is_zone_device_page(const struct page *page)
723 {
724         return false;
725 }
726 #endif
727 
728 static inline void get_page(struct page *page)
729 {
730         page = compound_head(page);
731         /*
732          * Getting a normal page or the head of a compound page
733          * requires to already have an elevated page->_count.
734          */
735         VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page);
736         page_ref_inc(page);
737 
738         if (unlikely(is_zone_device_page(page)))
739                 get_zone_device_page(page);
740 }
741 
742 static inline void put_page(struct page *page)
743 {
744         page = compound_head(page);
745 
746         if (put_page_testzero(page))
747                 __put_page(page);
748 
749         if (unlikely(is_zone_device_page(page)))
750                 put_zone_device_page(page);
751 }
752 
753 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
754 #define SECTION_IN_PAGE_FLAGS
755 #endif
756 
757 /*
758  * The identification function is mainly used by the buddy allocator for
759  * determining if two pages could be buddies. We are not really identifying
760  * the zone since we could be using the section number id if we do not have
761  * node id available in page flags.
762  * We only guarantee that it will return the same value for two combinable
763  * pages in a zone.
764  */
765 static inline int page_zone_id(struct page *page)
766 {
767         return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
768 }
769 
770 static inline int zone_to_nid(struct zone *zone)
771 {
772 #ifdef CONFIG_NUMA
773         return zone->node;
774 #else
775         return 0;
776 #endif
777 }
778 
779 #ifdef NODE_NOT_IN_PAGE_FLAGS
780 extern int page_to_nid(const struct page *page);
781 #else
782 static inline int page_to_nid(const struct page *page)
783 {
784         return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
785 }
786 #endif
787 
788 #ifdef CONFIG_NUMA_BALANCING
789 static inline int cpu_pid_to_cpupid(int cpu, int pid)
790 {
791         return ((cpu & LAST__CPU_MASK) << LAST__PID_SHIFT) | (pid & LAST__PID_MASK);
792 }
793 
794 static inline int cpupid_to_pid(int cpupid)
795 {
796         return cpupid & LAST__PID_MASK;
797 }
798 
799 static inline int cpupid_to_cpu(int cpupid)
800 {
801         return (cpupid >> LAST__PID_SHIFT) & LAST__CPU_MASK;
802 }
803 
804 static inline int cpupid_to_nid(int cpupid)
805 {
806         return cpu_to_node(cpupid_to_cpu(cpupid));
807 }
808 
809 static inline bool cpupid_pid_unset(int cpupid)
810 {
811         return cpupid_to_pid(cpupid) == (-1 & LAST__PID_MASK);
812 }
813 
814 static inline bool cpupid_cpu_unset(int cpupid)
815 {
816         return cpupid_to_cpu(cpupid) == (-1 & LAST__CPU_MASK);
817 }
818 
819 static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
820 {
821         return (task_pid & LAST__PID_MASK) == cpupid_to_pid(cpupid);
822 }
823 
824 #define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
825 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
826 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
827 {
828         return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
829 }
830 
831 static inline int page_cpupid_last(struct page *page)
832 {
833         return page->_last_cpupid;
834 }
835 static inline void page_cpupid_reset_last(struct page *page)
836 {
837         page->_last_cpupid = -1 & LAST_CPUPID_MASK;
838 }
839 #else
840 static inline int page_cpupid_last(struct page *page)
841 {
842         return (page->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
843 }
844 
845 extern int page_cpupid_xchg_last(struct page *page, int cpupid);
846 
847 static inline void page_cpupid_reset_last(struct page *page)
848 {
849         int cpupid = (1 << LAST_CPUPID_SHIFT) - 1;
850 
851         page->flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
852         page->flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
853 }
854 #endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
855 #else /* !CONFIG_NUMA_BALANCING */
856 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
857 {
858         return page_to_nid(page); /* XXX */
859 }
860 
861 static inline int page_cpupid_last(struct page *page)
862 {
863         return page_to_nid(page); /* XXX */
864 }
865 
866 static inline int cpupid_to_nid(int cpupid)
867 {
868         return -1;
869 }
870 
871 static inline int cpupid_to_pid(int cpupid)
872 {
873         return -1;
874 }
875 
876 static inline int cpupid_to_cpu(int cpupid)
877 {
878         return -1;
879 }
880 
881 static inline int cpu_pid_to_cpupid(int nid, int pid)
882 {
883         return -1;
884 }
885 
886 static inline bool cpupid_pid_unset(int cpupid)
887 {
888         return 1;
889 }
890 
891 static inline void page_cpupid_reset_last(struct page *page)
892 {
893 }
894 
895 static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
896 {
897         return false;
898 }
899 #endif /* CONFIG_NUMA_BALANCING */
900 
901 static inline struct zone *page_zone(const struct page *page)
902 {
903         return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
904 }
905 
906 #ifdef SECTION_IN_PAGE_FLAGS
907 static inline void set_page_section(struct page *page, unsigned long section)
908 {
909         page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
910         page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
911 }
912 
913 static inline unsigned long page_to_section(const struct page *page)
914 {
915         return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
916 }
917 #endif
918 
919 static inline void set_page_zone(struct page *page, enum zone_type zone)
920 {
921         page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
922         page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
923 }
924 
925 static inline void set_page_node(struct page *page, unsigned long node)
926 {
927         page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
928         page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
929 }
930 
931 static inline void set_page_links(struct page *page, enum zone_type zone,
932         unsigned long node, unsigned long pfn)
933 {
934         set_page_zone(page, zone);
935         set_page_node(page, node);
936 #ifdef SECTION_IN_PAGE_FLAGS
937         set_page_section(page, pfn_to_section_nr(pfn));
938 #endif
939 }
940 
941 #ifdef CONFIG_MEMCG
942 static inline struct mem_cgroup *page_memcg(struct page *page)
943 {
944         return page->mem_cgroup;
945 }
946 #else
947 static inline struct mem_cgroup *page_memcg(struct page *page)
948 {
949         return NULL;
950 }
951 #endif
952 
953 /*
954  * Some inline functions in vmstat.h depend on page_zone()
955  */
956 #include <linux/vmstat.h>
957 
958 static __always_inline void *lowmem_page_address(const struct page *page)
959 {
960         return __va(PFN_PHYS(page_to_pfn(page)));
961 }
962 
963 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
964 #define HASHED_PAGE_VIRTUAL
965 #endif
966 
967 #if defined(WANT_PAGE_VIRTUAL)
968 static inline void *page_address(const struct page *page)
969 {
970         return page->virtual;
971 }
972 static inline void set_page_address(struct page *page, void *address)
973 {
974         page->virtual = address;
975 }
976 #define page_address_init()  do { } while(0)
977 #endif
978 
979 #if defined(HASHED_PAGE_VIRTUAL)
980 void *page_address(const struct page *page);
981 void set_page_address(struct page *page, void *virtual);
982 void page_address_init(void);
983 #endif
984 
985 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
986 #define page_address(page) lowmem_page_address(page)
987 #define set_page_address(page, address)  do { } while(0)
988 #define page_address_init()  do { } while(0)
989 #endif
990 
991 extern void *page_rmapping(struct page *page);
992 extern struct anon_vma *page_anon_vma(struct page *page);
993 extern struct address_space *page_mapping(struct page *page);
994 
995 extern struct address_space *__page_file_mapping(struct page *);
996 
997 static inline
998 struct address_space *page_file_mapping(struct page *page)
999 {
1000         if (unlikely(PageSwapCache(page)))
1001                 return __page_file_mapping(page);
1002 
1003         return page->mapping;
1004 }
1005 
1006 /*
1007  * Return the pagecache index of the passed page.  Regular pagecache pages
1008  * use ->index whereas swapcache pages use ->private
1009  */
1010 static inline pgoff_t page_index(struct page *page)
1011 {
1012         if (unlikely(PageSwapCache(page)))
1013                 return page_private(page);
1014         return page->index;
1015 }
1016 
1017 extern pgoff_t __page_file_index(struct page *page);
1018 
1019 /*
1020  * Return the file index of the page. Regular pagecache pages use ->index
1021  * whereas swapcache pages use swp_offset(->private)
1022  */
1023 static inline pgoff_t page_file_index(struct page *page)
1024 {
1025         if (unlikely(PageSwapCache(page)))
1026                 return __page_file_index(page);
1027 
1028         return page->index;
1029 }
1030 
1031 /*
1032  * Return true if this page is mapped into pagetables.
1033  * For compound page it returns true if any subpage of compound page is mapped.
1034  */
1035 static inline bool page_mapped(struct page *page)
1036 {
1037         int i;
1038         if (likely(!PageCompound(page)))
1039                 return atomic_read(&page->_mapcount) >= 0;
1040         page = compound_head(page);
1041         if (atomic_read(compound_mapcount_ptr(page)) >= 0)
1042                 return true;
1043         if (PageHuge(page))
1044                 return false;
1045         for (i = 0; i < hpage_nr_pages(page); i++) {
1046                 if (atomic_read(&page[i]._mapcount) >= 0)
1047                         return true;
1048         }
1049         return false;
1050 }
1051 
1052 /*
1053  * Return true only if the page has been allocated with
1054  * ALLOC_NO_WATERMARKS and the low watermark was not
1055  * met implying that the system is under some pressure.
1056  */
1057 static inline bool page_is_pfmemalloc(struct page *page)
1058 {
1059         /*
1060          * Page index cannot be this large so this must be
1061          * a pfmemalloc page.
1062          */
1063         return page->index == -1UL;
1064 }
1065 
1066 /*
1067  * Only to be called by the page allocator on a freshly allocated
1068  * page.
1069  */
1070 static inline void set_page_pfmemalloc(struct page *page)
1071 {
1072         page->index = -1UL;
1073 }
1074 
1075 static inline void clear_page_pfmemalloc(struct page *page)
1076 {
1077         page->index = 0;
1078 }
1079 
1080 /*
1081  * Different kinds of faults, as returned by handle_mm_fault().
1082  * Used to decide whether a process gets delivered SIGBUS or
1083  * just gets major/minor fault counters bumped up.
1084  */
1085 
1086 #define VM_FAULT_OOM    0x0001
1087 #define VM_FAULT_SIGBUS 0x0002
1088 #define VM_FAULT_MAJOR  0x0004
1089 #define VM_FAULT_WRITE  0x0008  /* Special case for get_user_pages */
1090 #define VM_FAULT_HWPOISON 0x0010        /* Hit poisoned small page */
1091 #define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
1092 #define VM_FAULT_SIGSEGV 0x0040
1093 
1094 #define VM_FAULT_NOPAGE 0x0100  /* ->fault installed the pte, not return page */
1095 #define VM_FAULT_LOCKED 0x0200  /* ->fault locked the returned page */
1096 #define VM_FAULT_RETRY  0x0400  /* ->fault blocked, must retry */
1097 #define VM_FAULT_FALLBACK 0x0800        /* huge page fault failed, fall back to small */
1098 
1099 #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */
1100 
1101 #define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \
1102                          VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \
1103                          VM_FAULT_FALLBACK)
1104 
1105 /* Encode hstate index for a hwpoisoned large page */
1106 #define VM_FAULT_SET_HINDEX(x) ((x) << 12)
1107 #define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
1108 
1109 /*
1110  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
1111  */
1112 extern void pagefault_out_of_memory(void);
1113 
1114 #define offset_in_page(p)       ((unsigned long)(p) & ~PAGE_MASK)
1115 
1116 /*
1117  * Flags passed to show_mem() and show_free_areas() to suppress output in
1118  * various contexts.
1119  */
1120 #define SHOW_MEM_FILTER_NODES           (0x0001u)       /* disallowed nodes */
1121 
1122 extern void show_free_areas(unsigned int flags);
1123 extern bool skip_free_areas_node(unsigned int flags, int nid);
1124 
1125 int shmem_zero_setup(struct vm_area_struct *);
1126 #ifdef CONFIG_SHMEM
1127 bool shmem_mapping(struct address_space *mapping);
1128 #else
1129 static inline bool shmem_mapping(struct address_space *mapping)
1130 {
1131         return false;
1132 }
1133 #endif
1134 
1135 extern bool can_do_mlock(void);
1136 extern int user_shm_lock(size_t, struct user_struct *);
1137 extern void user_shm_unlock(size_t, struct user_struct *);
1138 
1139 /*
1140  * Parameter block passed down to zap_pte_range in exceptional cases.
1141  */
1142 struct zap_details {
1143         struct address_space *check_mapping;    /* Check page->mapping if set */
1144         pgoff_t first_index;                    /* Lowest page->index to unmap */
1145         pgoff_t last_index;                     /* Highest page->index to unmap */
1146         bool ignore_dirty;                      /* Ignore dirty pages */
1147         bool check_swap_entries;                /* Check also swap entries */
1148 };
1149 
1150 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
1151                 pte_t pte);
1152 struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
1153                                 pmd_t pmd);
1154 
1155 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1156                 unsigned long size);
1157 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
1158                 unsigned long size, struct zap_details *);
1159 void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
1160                 unsigned long start, unsigned long end);
1161 
1162 /**
1163  * mm_walk - callbacks for walk_page_range
1164  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
1165  *             this handler is required to be able to handle
1166  *             pmd_trans_huge() pmds.  They may simply choose to
1167  *             split_huge_page() instead of handling it explicitly.
1168  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
1169  * @pte_hole: if set, called for each hole at all levels
1170  * @hugetlb_entry: if set, called for each hugetlb entry
1171  * @test_walk: caller specific callback function to determine whether
1172  *             we walk over the current vma or not. A positive returned
1173  *             value means "do page table walk over the current vma,"
1174  *             and a negative one means "abort current page table walk
1175  *             right now." 0 means "skip the current vma."
1176  * @mm:        mm_struct representing the target process of page table walk
1177  * @vma:       vma currently walked (NULL if walking outside vmas)
1178  * @private:   private data for callbacks' usage
1179  *
1180  * (see the comment on walk_page_range() for more details)
1181  */
1182 struct mm_walk {
1183         int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
1184                          unsigned long next, struct mm_walk *walk);
1185         int (*pte_entry)(pte_t *pte, unsigned long addr,
1186                          unsigned long next, struct mm_walk *walk);
1187         int (*pte_hole)(unsigned long addr, unsigned long next,
1188                         struct mm_walk *walk);
1189         int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
1190                              unsigned long addr, unsigned long next,
1191                              struct mm_walk *walk);
1192         int (*test_walk)(unsigned long addr, unsigned long next,
1193                         struct mm_walk *walk);
1194         struct mm_struct *mm;
1195         struct vm_area_struct *vma;
1196         void *private;
1197 };
1198 
1199 int walk_page_range(unsigned long addr, unsigned long end,
1200                 struct mm_walk *walk);
1201 int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
1202 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
1203                 unsigned long end, unsigned long floor, unsigned long ceiling);
1204 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
1205                         struct vm_area_struct *vma);
1206 void unmap_mapping_range(struct address_space *mapping,
1207                 loff_t const holebegin, loff_t const holelen, int even_cows);
1208 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
1209         unsigned long *pfn);
1210 int follow_phys(struct vm_area_struct *vma, unsigned long address,
1211                 unsigned int flags, unsigned long *prot, resource_size_t *phys);
1212 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
1213                         void *buf, int len, int write);
1214 
1215 static inline void unmap_shared_mapping_range(struct address_space *mapping,
1216                 loff_t const holebegin, loff_t const holelen)
1217 {
1218         unmap_mapping_range(mapping, holebegin, holelen, 0);
1219 }
1220 
1221 extern void truncate_pagecache(struct inode *inode, loff_t new);
1222 extern void truncate_setsize(struct inode *inode, loff_t newsize);
1223 void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to);
1224 void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end);
1225 int truncate_inode_page(struct address_space *mapping, struct page *page);
1226 int generic_error_remove_page(struct address_space *mapping, struct page *page);
1227 int invalidate_inode_page(struct page *page);
1228 
1229 #ifdef CONFIG_MMU
1230 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
1231                         unsigned long address, unsigned int flags);
1232 extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1233                             unsigned long address, unsigned int fault_flags,
1234                             bool *unlocked);
1235 #else
1236 static inline int handle_mm_fault(struct mm_struct *mm,
1237                         struct vm_area_struct *vma, unsigned long address,
1238                         unsigned int flags)
1239 {
1240         /* should never happen if there's no MMU */
1241         BUG();
1242         return VM_FAULT_SIGBUS;
1243 }
1244 static inline int fixup_user_fault(struct task_struct *tsk,
1245                 struct mm_struct *mm, unsigned long address,
1246                 unsigned int fault_flags, bool *unlocked)
1247 {
1248         /* should never happen if there's no MMU */
1249         BUG();
1250         return -EFAULT;
1251 }
1252 #endif
1253 
1254 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
1255 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1256                 void *buf, int len, int write);
1257 
1258 long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1259                       unsigned long start, unsigned long nr_pages,
1260                       unsigned int foll_flags, struct page **pages,
1261                       struct vm_area_struct **vmas, int *nonblocking);
1262 long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
1263                             unsigned long start, unsigned long nr_pages,
1264                             int write, int force, struct page **pages,
1265                             struct vm_area_struct **vmas);
1266 long get_user_pages(unsigned long start, unsigned long nr_pages,
1267                             int write, int force, struct page **pages,
1268                             struct vm_area_struct **vmas);
1269 long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
1270                     int write, int force, struct page **pages, int *locked);
1271 long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
1272                                unsigned long start, unsigned long nr_pages,
1273                                int write, int force, struct page **pages,
1274                                unsigned int gup_flags);
1275 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
1276                     int write, int force, struct page **pages);
1277 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
1278                         struct page **pages);
1279 
1280 /* Container for pinned pfns / pages */
1281 struct frame_vector {
1282         unsigned int nr_allocated;      /* Number of frames we have space for */
1283         unsigned int nr_frames; /* Number of frames stored in ptrs array */
1284         bool got_ref;           /* Did we pin pages by getting page ref? */
1285         bool is_pfns;           /* Does array contain pages or pfns? */
1286         void *ptrs[0];          /* Array of pinned pfns / pages. Use
1287                                  * pfns_vector_pages() or pfns_vector_pfns()
1288                                  * for access */
1289 };
1290 
1291 struct frame_vector *frame_vector_create(unsigned int nr_frames);
1292 void frame_vector_destroy(struct frame_vector *vec);
1293 int get_vaddr_frames(unsigned long start, unsigned int nr_pfns,
1294                      bool write, bool force, struct frame_vector *vec);
1295 void put_vaddr_frames(struct frame_vector *vec);
1296 int frame_vector_to_pages(struct frame_vector *vec);
1297 void frame_vector_to_pfns(struct frame_vector *vec);
1298 
1299 static inline unsigned int frame_vector_count(struct frame_vector *vec)
1300 {
1301         return vec->nr_frames;
1302 }
1303 
1304 static inline struct page **frame_vector_pages(struct frame_vector *vec)
1305 {
1306         if (vec->is_pfns) {
1307                 int err = frame_vector_to_pages(vec);
1308 
1309                 if (err)
1310                         return ERR_PTR(err);
1311         }
1312         return (struct page **)(vec->ptrs);
1313 }
1314 
1315 static inline unsigned long *frame_vector_pfns(struct frame_vector *vec)
1316 {
1317         if (!vec->is_pfns)
1318                 frame_vector_to_pfns(vec);
1319         return (unsigned long *)(vec->ptrs);
1320 }
1321 
1322 struct kvec;
1323 int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
1324                         struct page **pages);
1325 int get_kernel_page(unsigned long start, int write, struct page **pages);
1326 struct page *get_dump_page(unsigned long addr);
1327 
1328 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
1329 extern void do_invalidatepage(struct page *page, unsigned int offset,
1330                               unsigned int length);
1331 
1332 int __set_page_dirty_nobuffers(struct page *page);
1333 int __set_page_dirty_no_writeback(struct page *page);
1334 int redirty_page_for_writepage(struct writeback_control *wbc,
1335                                 struct page *page);
1336 void account_page_dirtied(struct page *page, struct address_space *mapping);
1337 void account_page_cleaned(struct page *page, struct address_space *mapping,
1338                           struct bdi_writeback *wb);
1339 int set_page_dirty(struct page *page);
1340 int set_page_dirty_lock(struct page *page);
1341 void cancel_dirty_page(struct page *page);
1342 int clear_page_dirty_for_io(struct page *page);
1343 
1344 int get_cmdline(struct task_struct *task, char *buffer, int buflen);
1345 
1346 /* Is the vma a continuation of the stack vma above it? */
1347 static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
1348 {
1349         return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
1350 }
1351 
1352 static inline bool vma_is_anonymous(struct vm_area_struct *vma)
1353 {
1354         return !vma->vm_ops;
1355 }
1356 
1357 static inline int stack_guard_page_start(struct vm_area_struct *vma,
1358                                              unsigned long addr)
1359 {
1360         return (vma->vm_flags & VM_GROWSDOWN) &&
1361                 (vma->vm_start == addr) &&
1362                 !vma_growsdown(vma->vm_prev, addr);
1363 }
1364 
1365 /* Is the vma a continuation of the stack vma below it? */
1366 static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
1367 {
1368         return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
1369 }
1370 
1371 static inline int stack_guard_page_end(struct vm_area_struct *vma,
1372                                            unsigned long addr)
1373 {
1374         return (vma->vm_flags & VM_GROWSUP) &&
1375                 (vma->vm_end == addr) &&
1376                 !vma_growsup(vma->vm_next, addr);
1377 }
1378 
1379 int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t);
1380 
1381 extern unsigned long move_page_tables(struct vm_area_struct *vma,
1382                 unsigned long old_addr, struct vm_area_struct *new_vma,
1383                 unsigned long new_addr, unsigned long len,
1384                 bool need_rmap_locks);
1385 extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
1386                               unsigned long end, pgprot_t newprot,
1387                               int dirty_accountable, int prot_numa);
1388 extern int mprotect_fixup(struct vm_area_struct *vma,
1389                           struct vm_area_struct **pprev, unsigned long start,
1390                           unsigned long end, unsigned long newflags);
1391 
1392 /*
1393  * doesn't attempt to fault and will return short.
1394  */
1395 int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
1396                           struct page **pages);
1397 /*
1398  * per-process(per-mm_struct) statistics.
1399  */
1400 static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
1401 {
1402         long val = atomic_long_read(&mm->rss_stat.count[member]);
1403 
1404 #ifdef SPLIT_RSS_COUNTING
1405         /*
1406          * counter is updated in asynchronous manner and may go to minus.
1407          * But it's never be expected number for users.
1408          */
1409         if (val < 0)
1410                 val = 0;
1411 #endif
1412         return (unsigned long)val;
1413 }
1414 
1415 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
1416 {
1417         atomic_long_add(value, &mm->rss_stat.count[member]);
1418 }
1419 
1420 static inline void inc_mm_counter(struct mm_struct *mm, int member)
1421 {
1422         atomic_long_inc(&mm->rss_stat.count[member]);
1423 }
1424 
1425 static inline void dec_mm_counter(struct mm_struct *mm, int member)
1426 {
1427         atomic_long_dec(&mm->rss_stat.count[member]);
1428 }
1429 
1430 /* Optimized variant when page is already known not to be PageAnon */
1431 static inline int mm_counter_file(struct page *page)
1432 {
1433         if (PageSwapBacked(page))
1434                 return MM_SHMEMPAGES;
1435         return MM_FILEPAGES;
1436 }
1437 
1438 static inline int mm_counter(struct page *page)
1439 {
1440         if (PageAnon(page))
1441                 return MM_ANONPAGES;
1442         return mm_counter_file(page);
1443 }
1444 
1445 static inline unsigned long get_mm_rss(struct mm_struct *mm)
1446 {
1447         return get_mm_counter(mm, MM_FILEPAGES) +
1448                 get_mm_counter(mm, MM_ANONPAGES) +
1449                 get_mm_counter(mm, MM_SHMEMPAGES);
1450 }
1451 
1452 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
1453 {
1454         return max(mm->hiwater_rss, get_mm_rss(mm));
1455 }
1456 
1457 static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
1458 {
1459         return max(mm->hiwater_vm, mm->total_vm);
1460 }
1461 
1462 static inline void update_hiwater_rss(struct mm_struct *mm)
1463 {
1464         unsigned long _rss = get_mm_rss(mm);
1465 
1466         if ((mm)->hiwater_rss < _rss)
1467                 (mm)->hiwater_rss = _rss;
1468 }
1469 
1470 static inline void update_hiwater_vm(struct mm_struct *mm)
1471 {
1472         if (mm->hiwater_vm < mm->total_vm)
1473                 mm->hiwater_vm = mm->total_vm;
1474 }
1475 
1476 static inline void reset_mm_hiwater_rss(struct mm_struct *mm)
1477 {
1478         mm->hiwater_rss = get_mm_rss(mm);
1479 }
1480 
1481 static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
1482                                          struct mm_struct *mm)
1483 {
1484         unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
1485 
1486         if (*maxrss < hiwater_rss)
1487                 *maxrss = hiwater_rss;
1488 }
1489 
1490 #if defined(SPLIT_RSS_COUNTING)
1491 void sync_mm_rss(struct mm_struct *mm);
1492 #else
1493 static inline void sync_mm_rss(struct mm_struct *mm)
1494 {
1495 }
1496 #endif
1497 
1498 #ifndef __HAVE_ARCH_PTE_DEVMAP
1499 static inline int pte_devmap(pte_t pte)
1500 {
1501         return 0;
1502 }
1503 #endif
1504 
1505 int vma_wants_writenotify(struct vm_area_struct *vma);
1506 
1507 extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1508                                spinlock_t **ptl);
1509 static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1510                                     spinlock_t **ptl)
1511 {
1512         pte_t *ptep;
1513         __cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
1514         return ptep;
1515 }
1516 
1517 #ifdef __PAGETABLE_PUD_FOLDED
1518 static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
1519                                                 unsigned long address)
1520 {
1521         return 0;
1522 }
1523 #else
1524 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
1525 #endif
1526 
1527 #if defined(__PAGETABLE_PMD_FOLDED) || !defined(CONFIG_MMU)
1528 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
1529                                                 unsigned long address)
1530 {
1531         return 0;
1532 }
1533 
1534 static inline void mm_nr_pmds_init(struct mm_struct *mm) {}
1535 
1536 static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
1537 {
1538         return 0;
1539 }
1540 
1541 static inline void mm_inc_nr_pmds(struct mm_struct *mm) {}
1542 static inline void mm_dec_nr_pmds(struct mm_struct *mm) {}
1543 
1544 #else
1545 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
1546 
1547 static inline void mm_nr_pmds_init(struct mm_struct *mm)
1548 {
1549         atomic_long_set(&mm->nr_pmds, 0);
1550 }
1551 
1552 static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
1553 {
1554         return atomic_long_read(&mm->nr_pmds);
1555 }
1556 
1557 static inline void mm_inc_nr_pmds(struct mm_struct *mm)
1558 {
1559         atomic_long_inc(&mm->nr_pmds);
1560 }
1561 
1562 static inline void mm_dec_nr_pmds(struct mm_struct *mm)
1563 {
1564         atomic_long_dec(&mm->nr_pmds);
1565 }
1566 #endif
1567 
1568 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);
1569 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
1570 
1571 /*
1572  * The following ifdef needed to get the 4level-fixup.h header to work.
1573  * Remove it when 4level-fixup.h has been removed.
1574  */
1575 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
1576 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
1577 {
1578         return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
1579                 NULL: pud_offset(pgd, address);
1580 }
1581 
1582 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
1583 {
1584         return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
1585                 NULL: pmd_offset(pud, address);
1586 }
1587 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
1588 
1589 #if USE_SPLIT_PTE_PTLOCKS
1590 #if ALLOC_SPLIT_PTLOCKS
1591 void __init ptlock_cache_init(void);
1592 extern bool ptlock_alloc(struct page *page);
1593 extern void ptlock_free(struct page *page);
1594 
1595 static inline spinlock_t *ptlock_ptr(struct page *page)
1596 {
1597         return page->ptl;
1598 }
1599 #else /* ALLOC_SPLIT_PTLOCKS */
1600 static inline void ptlock_cache_init(void)
1601 {
1602 }
1603 
1604 static inline bool ptlock_alloc(struct page *page)
1605 {
1606         return true;
1607 }
1608 
1609 static inline void ptlock_free(struct page *page)
1610 {
1611 }
1612 
1613 static inline spinlock_t *ptlock_ptr(struct page *page)
1614 {
1615         return &page->ptl;
1616 }
1617 #endif /* ALLOC_SPLIT_PTLOCKS */
1618 
1619 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1620 {
1621         return ptlock_ptr(pmd_page(*pmd));
1622 }
1623 
1624 static inline bool ptlock_init(struct page *page)
1625 {
1626         /*
1627          * prep_new_page() initialize page->private (and therefore page->ptl)
1628          * with 0. Make sure nobody took it in use in between.
1629          *
1630          * It can happen if arch try to use slab for page table allocation:
1631          * slab code uses page->slab_cache, which share storage with page->ptl.
1632          */
1633         VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
1634         if (!ptlock_alloc(page))
1635                 return false;
1636         spin_lock_init(ptlock_ptr(page));
1637         return true;
1638 }
1639 
1640 /* Reset page->mapping so free_pages_check won't complain. */
1641 static inline void pte_lock_deinit(struct page *page)
1642 {
1643         page->mapping = NULL;
1644         ptlock_free(page);
1645 }
1646 
1647 #else   /* !USE_SPLIT_PTE_PTLOCKS */
1648 /*
1649  * We use mm->page_table_lock to guard all pagetable pages of the mm.
1650  */
1651 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1652 {
1653         return &mm->page_table_lock;
1654 }
1655 static inline void ptlock_cache_init(void) {}
1656 static inline bool ptlock_init(struct page *page) { return true; }
1657 static inline void pte_lock_deinit(struct page *page) {}
1658 #endif /* USE_SPLIT_PTE_PTLOCKS */
1659 
1660 static inline void pgtable_init(void)
1661 {
1662         ptlock_cache_init();
1663         pgtable_cache_init();
1664 }
1665 
1666 static inline bool pgtable_page_ctor(struct page *page)
1667 {
1668         if (!ptlock_init(page))
1669                 return false;
1670         inc_zone_page_state(page, NR_PAGETABLE);
1671         return true;
1672 }
1673 
1674 static inline void pgtable_page_dtor(struct page *page)
1675 {
1676         pte_lock_deinit(page);
1677         dec_zone_page_state(page, NR_PAGETABLE);
1678 }
1679 
1680 #define pte_offset_map_lock(mm, pmd, address, ptlp)     \
1681 ({                                                      \
1682         spinlock_t *__ptl = pte_lockptr(mm, pmd);       \
1683         pte_t *__pte = pte_offset_map(pmd, address);    \
1684         *(ptlp) = __ptl;                                \
1685         spin_lock(__ptl);                               \
1686         __pte;                                          \
1687 })
1688 
1689 #define pte_unmap_unlock(pte, ptl)      do {            \
1690         spin_unlock(ptl);                               \
1691         pte_unmap(pte);                                 \
1692 } while (0)
1693 
1694 #define pte_alloc(mm, pmd, address)                     \
1695         (unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, pmd, address))
1696 
1697 #define pte_alloc_map(mm, pmd, address)                 \
1698         (pte_alloc(mm, pmd, address) ? NULL : pte_offset_map(pmd, address))
1699 
1700 #define pte_alloc_map_lock(mm, pmd, address, ptlp)      \
1701         (pte_alloc(mm, pmd, address) ?                  \
1702                  NULL : pte_offset_map_lock(mm, pmd, address, ptlp))
1703 
1704 #define pte_alloc_kernel(pmd, address)                  \
1705         ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
1706                 NULL: pte_offset_kernel(pmd, address))
1707 
1708 #if USE_SPLIT_PMD_PTLOCKS
1709 
1710 static struct page *pmd_to_page(pmd_t *pmd)
1711 {
1712         unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
1713         return virt_to_page((void *)((unsigned long) pmd & mask));
1714 }
1715 
1716 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1717 {
1718         return ptlock_ptr(pmd_to_page(pmd));
1719 }
1720 
1721 static inline bool pgtable_pmd_page_ctor(struct page *page)
1722 {
1723 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1724         page->pmd_huge_pte = NULL;
1725 #endif
1726         return ptlock_init(page);
1727 }
1728 
1729 static inline void pgtable_pmd_page_dtor(struct page *page)
1730 {
1731 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1732         VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
1733 #endif
1734         ptlock_free(page);
1735 }
1736 
1737 #define pmd_huge_pte(mm, pmd) (pmd_to_page(pmd)->pmd_huge_pte)
1738 
1739 #else
1740 
1741 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1742 {
1743         return &mm->page_table_lock;
1744 }
1745 
1746 static inline bool pgtable_pmd_page_ctor(struct page *page) { return true; }
1747 static inline void pgtable_pmd_page_dtor(struct page *page) {}
1748 
1749 #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
1750 
1751 #endif
1752 
1753 static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
1754 {
1755         spinlock_t *ptl = pmd_lockptr(mm, pmd);
1756         spin_lock(ptl);
1757         return ptl;
1758 }
1759 
1760 extern void free_area_init(unsigned long * zones_size);
1761 extern void free_area_init_node(int nid, unsigned long * zones_size,
1762                 unsigned long zone_start_pfn, unsigned long *zholes_size);
1763 extern void free_initmem(void);
1764 
1765 /*
1766  * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
1767  * into the buddy system. The freed pages will be poisoned with pattern
1768  * "poison" if it's within range [0, UCHAR_MAX].
1769  * Return pages freed into the buddy system.
1770  */
1771 extern unsigned long free_reserved_area(void *start, void *end,
1772                                         int poison, char *s);
1773 
1774 #ifdef  CONFIG_HIGHMEM
1775 /*
1776  * Free a highmem page into the buddy system, adjusting totalhigh_pages
1777  * and totalram_pages.
1778  */
1779 extern void free_highmem_page(struct page *page);
1780 #endif
1781 
1782 extern void adjust_managed_page_count(struct page *page, long count);
1783 extern void mem_init_print_info(const char *str);
1784 
1785 extern void reserve_bootmem_region(unsigned long start, unsigned long end);
1786 
1787 /* Free the reserved page into the buddy system, so it gets managed. */
1788 static inline void __free_reserved_page(struct page *page)
1789 {
1790         ClearPageReserved(page);
1791         init_page_count(page);
1792         __free_page(page);
1793 }
1794 
1795 static inline void free_reserved_page(struct page *page)
1796 {
1797         __free_reserved_page(page);
1798         adjust_managed_page_count(page, 1);
1799 }
1800 
1801 static inline void mark_page_reserved(struct page *page)
1802 {
1803         SetPageReserved(page);
1804         adjust_managed_page_count(page, -1);
1805 }
1806 
1807 /*
1808  * Default method to free all the __init memory into the buddy system.
1809  * The freed pages will be poisoned with pattern "poison" if it's within
1810  * range [0, UCHAR_MAX].
1811  * Return pages freed into the buddy system.
1812  */
1813 static inline unsigned long free_initmem_default(int poison)
1814 {
1815         extern char __init_begin[], __init_end[];
1816 
1817         return free_reserved_area(&__init_begin, &__init_end,
1818                                   poison, "unused kernel");
1819 }
1820 
1821 static inline unsigned long get_num_physpages(void)
1822 {
1823         int nid;
1824         unsigned long phys_pages = 0;
1825 
1826         for_each_online_node(nid)
1827                 phys_pages += node_present_pages(nid);
1828 
1829         return phys_pages;
1830 }
1831 
1832 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1833 /*
1834  * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
1835  * zones, allocate the backing mem_map and account for memory holes in a more
1836  * architecture independent manner. This is a substitute for creating the
1837  * zone_sizes[] and zholes_size[] arrays and passing them to
1838  * free_area_init_node()
1839  *
1840  * An architecture is expected to register range of page frames backed by
1841  * physical memory with memblock_add[_node]() before calling
1842  * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
1843  * usage, an architecture is expected to do something like
1844  *
1845  * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
1846  *                                                       max_highmem_pfn};
1847  * for_each_valid_physical_page_range()
1848  *      memblock_add_node(base, size, nid)
1849  * free_area_init_nodes(max_zone_pfns);
1850  *
1851  * free_bootmem_with_active_regions() calls free_bootmem_node() for each
1852  * registered physical page range.  Similarly
1853  * sparse_memory_present_with_active_regions() calls memory_present() for
1854  * each range when SPARSEMEM is enabled.
1855  *
1856  * See mm/page_alloc.c for more information on each function exposed by
1857  * CONFIG_HAVE_MEMBLOCK_NODE_MAP.
1858  */
1859 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
1860 unsigned long node_map_pfn_alignment(void);
1861 unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
1862                                                 unsigned long end_pfn);
1863 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
1864                                                 unsigned long end_pfn);
1865 extern void get_pfn_range_for_nid(unsigned int nid,
1866                         unsigned long *start_pfn, unsigned long *end_pfn);
1867 extern unsigned long find_min_pfn_with_active_regions(void);
1868 extern void free_bootmem_with_active_regions(int nid,
1869                                                 unsigned long max_low_pfn);
1870 extern void sparse_memory_present_with_active_regions(int nid);
1871 
1872 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
1873 
1874 #if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
1875     !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
1876 static inline int __early_pfn_to_nid(unsigned long pfn,
1877                                         struct mminit_pfnnid_cache *state)
1878 {
1879         return 0;
1880 }
1881 #else
1882 /* please see mm/page_alloc.c */
1883 extern int __meminit early_pfn_to_nid(unsigned long pfn);
1884 /* there is a per-arch backend function. */
1885 extern int __meminit __early_pfn_to_nid(unsigned long pfn,
1886                                         struct mminit_pfnnid_cache *state);
1887 #endif
1888 
1889 extern void set_dma_reserve(unsigned long new_dma_reserve);
1890 extern void memmap_init_zone(unsigned long, int, unsigned long,
1891                                 unsigned long, enum memmap_context);
1892 extern void setup_per_zone_wmarks(void);
1893 extern int __meminit init_per_zone_wmark_min(void);
1894 extern void mem_init(void);
1895 extern void __init mmap_init(void);
1896 extern void show_mem(unsigned int flags);
1897 extern long si_mem_available(void);
1898 extern void si_meminfo(struct sysinfo * val);
1899 extern void si_meminfo_node(struct sysinfo *val, int nid);
1900 
1901 extern __printf(3, 4)
1902 void warn_alloc_failed(gfp_t gfp_mask, unsigned int order,
1903                 const char *fmt, ...);
1904 
1905 extern void setup_per_cpu_pageset(void);
1906 
1907 extern void zone_pcp_update(struct zone *zone);
1908 extern void zone_pcp_reset(struct zone *zone);
1909 
1910 /* page_alloc.c */
1911 extern int min_free_kbytes;
1912 extern int watermark_scale_factor;
1913 
1914 /* nommu.c */
1915 extern atomic_long_t mmap_pages_allocated;
1916 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
1917 
1918 /* interval_tree.c */
1919 void vma_interval_tree_insert(struct vm_area_struct *node,
1920                               struct rb_root *root);
1921 void vma_interval_tree_insert_after(struct vm_area_struct *node,
1922                                     struct vm_area_struct *prev,
1923                                     struct rb_root *root);
1924 void vma_interval_tree_remove(struct vm_area_struct *node,
1925                               struct rb_root *root);
1926 struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root *root,
1927                                 unsigned long start, unsigned long last);
1928 struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
1929                                 unsigned long start, unsigned long last);
1930 
1931 #define vma_interval_tree_foreach(vma, root, start, last)               \
1932         for (vma = vma_interval_tree_iter_first(root, start, last);     \
1933              vma; vma = vma_interval_tree_iter_next(vma, start, last))
1934 
1935 void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
1936                                    struct rb_root *root);
1937 void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
1938                                    struct rb_root *root);
1939 struct anon_vma_chain *anon_vma_interval_tree_iter_first(
1940         struct rb_root *root, unsigned long start, unsigned long last);
1941 struct anon_vma_chain *anon_vma_interval_tree_iter_next(
1942         struct anon_vma_chain *node, unsigned long start, unsigned long last);
1943 #ifdef CONFIG_DEBUG_VM_RB
1944 void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
1945 #endif
1946 
1947 #define anon_vma_interval_tree_foreach(avc, root, start, last)           \
1948         for (avc = anon_vma_interval_tree_iter_first(root, start, last); \
1949              avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
1950 
1951 /* mmap.c */
1952 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
1953 extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
1954         unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
1955 extern struct vm_area_struct *vma_merge(struct mm_struct *,
1956         struct vm_area_struct *prev, unsigned long addr, unsigned long end,
1957         unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
1958         struct mempolicy *, struct vm_userfaultfd_ctx);
1959 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
1960 extern int split_vma(struct mm_struct *,
1961         struct vm_area_struct *, unsigned long addr, int new_below);
1962 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
1963 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
1964         struct rb_node **, struct rb_node *);
1965 extern void unlink_file_vma(struct vm_area_struct *);
1966 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
1967         unsigned long addr, unsigned long len, pgoff_t pgoff,
1968         bool *need_rmap_locks);
1969 extern void exit_mmap(struct mm_struct *);
1970 
1971 static inline int check_data_rlimit(unsigned long rlim,
1972                                     unsigned long new,
1973                                     unsigned long start,
1974                                     unsigned long end_data,
1975                                     unsigned long start_data)
1976 {
1977         if (rlim < RLIM_INFINITY) {
1978                 if (((new - start) + (end_data - start_data)) > rlim)
1979                         return -ENOSPC;
1980         }
1981 
1982         return 0;
1983 }
1984 
1985 extern int mm_take_all_locks(struct mm_struct *mm);
1986 extern void mm_drop_all_locks(struct mm_struct *mm);
1987 
1988 extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
1989 extern struct file *get_mm_exe_file(struct mm_struct *mm);
1990 
1991 extern bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long npages);
1992 extern void vm_stat_account(struct mm_struct *, vm_flags_t, long npages);
1993 
1994 extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
1995                                    unsigned long addr, unsigned long len,
1996                                    unsigned long flags,
1997                                    const struct vm_special_mapping *spec);
1998 /* This is an obsolete alternative to _install_special_mapping. */
1999 extern int install_special_mapping(struct mm_struct *mm,
2000                                    unsigned long addr, unsigned long len,
2001                                    unsigned long flags, struct page **pages);
2002 
2003 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
2004 
2005 extern unsigned long mmap_region(struct file *file, unsigned long addr,
2006         unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
2007 extern unsigned long do_mmap(struct file *file, unsigned long addr,
2008         unsigned long len, unsigned long prot, unsigned long flags,
2009         vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate);
2010 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
2011 
2012 static inline unsigned long
2013 do_mmap_pgoff(struct file *file, unsigned long addr,
2014         unsigned long len, unsigned long prot, unsigned long flags,
2015         unsigned long pgoff, unsigned long *populate)
2016 {
2017         return do_mmap(file, addr, len, prot, flags, 0, pgoff, populate);
2018 }
2019 
2020 #ifdef CONFIG_MMU
2021 extern int __mm_populate(unsigned long addr, unsigned long len,
2022                          int ignore_errors);
2023 static inline void mm_populate(unsigned long addr, unsigned long len)
2024 {
2025         /* Ignore errors */
2026         (void) __mm_populate(addr, len, 1);
2027 }
2028 #else
2029 static inline void mm_populate(unsigned long addr, unsigned long len) {}
2030 #endif
2031 
2032 /* These take the mm semaphore themselves */
2033 extern unsigned long vm_brk(unsigned long, unsigned long);
2034 extern int vm_munmap(unsigned long, size_t);
2035 extern unsigned long vm_mmap(struct file *, unsigned long,
2036         unsigned long, unsigned long,
2037         unsigned long, unsigned long);
2038 
2039 struct vm_unmapped_area_info {
2040 #define VM_UNMAPPED_AREA_TOPDOWN 1
2041         unsigned long flags;
2042         unsigned long length;
2043         unsigned long low_limit;
2044         unsigned long high_limit;
2045         unsigned long align_mask;
2046         unsigned long align_offset;
2047 };
2048 
2049 extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
2050 extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
2051 
2052 /*
2053  * Search for an unmapped address range.
2054  *
2055  * We are looking for a range that:
2056  * - does not intersect with any VMA;
2057  * - is contained within the [low_limit, high_limit) interval;
2058  * - is at least the desired size.
2059  * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
2060  */
2061 static inline unsigned long
2062 vm_unmapped_area(struct vm_unmapped_area_info *info)
2063 {
2064         if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
2065                 return unmapped_area_topdown(info);
2066         else
2067                 return unmapped_area(info);
2068 }
2069 
2070 /* truncate.c */
2071 extern void truncate_inode_pages(struct address_space *, loff_t);
2072 extern void truncate_inode_pages_range(struct address_space *,
2073                                        loff_t lstart, loff_t lend);
2074 extern void truncate_inode_pages_final(struct address_space *);
2075 
2076 /* generic vm_area_ops exported for stackable file systems */
2077 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
2078 extern void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf);
2079 extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
2080 
2081 /* mm/page-writeback.c */
2082 int write_one_page(struct page *page, int wait);
2083 void task_dirty_inc(struct task_struct *tsk);
2084 
2085 /* readahead.c */
2086 #define VM_MAX_READAHEAD        128     /* kbytes */
2087 #define VM_MIN_READAHEAD        16      /* kbytes (includes current page) */
2088 
2089 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
2090                         pgoff_t offset, unsigned long nr_to_read);
2091 
2092 void page_cache_sync_readahead(struct address_space *mapping,
2093                                struct file_ra_state *ra,
2094                                struct file *filp,
2095                                pgoff_t offset,
2096                                unsigned long size);
2097 
2098 void page_cache_async_readahead(struct address_space *mapping,
2099                                 struct file_ra_state *ra,
2100                                 struct file *filp,
2101                                 struct page *pg,
2102                                 pgoff_t offset,
2103                                 unsigned long size);
2104 
2105 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
2106 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
2107 
2108 /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
2109 extern int expand_downwards(struct vm_area_struct *vma,
2110                 unsigned long address);
2111 #if VM_GROWSUP
2112 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
2113 #else
2114   #define expand_upwards(vma, address) (0)
2115 #endif
2116 
2117 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
2118 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
2119 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
2120                                              struct vm_area_struct **pprev);
2121 
2122 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
2123    NULL if none.  Assume start_addr < end_addr. */
2124 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
2125 {
2126         struct vm_area_struct * vma = find_vma(mm,start_addr);
2127 
2128         if (vma && end_addr <= vma->vm_start)
2129                 vma = NULL;
2130         return vma;
2131 }
2132 
2133 static inline unsigned long vma_pages(struct vm_area_struct *vma)
2134 {
2135         return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
2136 }
2137 
2138 /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
2139 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
2140                                 unsigned long vm_start, unsigned long vm_end)
2141 {
2142         struct vm_area_struct *vma = find_vma(mm, vm_start);
2143 
2144         if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
2145                 vma = NULL;
2146 
2147         return vma;
2148 }
2149 
2150 #ifdef CONFIG_MMU
2151 pgprot_t vm_get_page_prot(unsigned long vm_flags);
2152 void vma_set_page_prot(struct vm_area_struct *vma);
2153 #else
2154 static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
2155 {
2156         return __pgprot(0);
2157 }
2158 static inline void vma_set_page_prot(struct vm_area_struct *vma)
2159 {
2160         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
2161 }
2162 #endif
2163 
2164 #ifdef CONFIG_NUMA_BALANCING
2165 unsigned long change_prot_numa(struct vm_area_struct *vma,
2166                         unsigned long start, unsigned long end);
2167 #endif
2168 
2169 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
2170 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
2171                         unsigned long pfn, unsigned long size, pgprot_t);
2172 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
2173 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2174                         unsigned long pfn);
2175 int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
2176                         unsigned long pfn, pgprot_t pgprot);
2177 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2178                         pfn_t pfn);
2179 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
2180 
2181 
2182 struct page *follow_page_mask(struct vm_area_struct *vma,
2183                               unsigned long address, unsigned int foll_flags,
2184                               unsigned int *page_mask);
2185 
2186 static inline struct page *follow_page(struct vm_area_struct *vma,
2187                 unsigned long address, unsigned int foll_flags)
2188 {
2189         unsigned int unused_page_mask;
2190         return follow_page_mask(vma, address, foll_flags, &unused_page_mask);
2191 }
2192 
2193 #define FOLL_WRITE      0x01    /* check pte is writable */
2194 #define FOLL_TOUCH      0x02    /* mark page accessed */
2195 #define FOLL_GET        0x04    /* do get_page on page */
2196 #define FOLL_DUMP       0x08    /* give error on hole if it would be zero */
2197 #define FOLL_FORCE      0x10    /* get_user_pages read/write w/o permission */
2198 #define FOLL_NOWAIT     0x20    /* if a disk transfer is needed, start the IO
2199                                  * and return without waiting upon it */
2200 #define FOLL_POPULATE   0x40    /* fault in page */
2201 #define FOLL_SPLIT      0x80    /* don't return transhuge pages, split them */
2202 #define FOLL_HWPOISON   0x100   /* check page is hwpoisoned */
2203 #define FOLL_NUMA       0x200   /* force NUMA hinting page fault */
2204 #define FOLL_MIGRATION  0x400   /* wait for page to replace migration entry */
2205 #define FOLL_TRIED      0x800   /* a retry, previous pass started an IO */
2206 #define FOLL_MLOCK      0x1000  /* lock present pages */
2207 #define FOLL_REMOTE     0x2000  /* we are working on non-current tsk/mm */
2208 
2209 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
2210                         void *data);
2211 extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
2212                                unsigned long size, pte_fn_t fn, void *data);
2213 
2214 
2215 #ifdef CONFIG_PAGE_POISONING
2216 extern bool page_poisoning_enabled(void);
2217 extern void kernel_poison_pages(struct page *page, int numpages, int enable);
2218 extern bool page_is_poisoned(struct page *page);
2219 #else
2220 static inline bool page_poisoning_enabled(void) { return false; }
2221 static inline void kernel_poison_pages(struct page *page, int numpages,
2222                                         int enable) { }
2223 static inline bool page_is_poisoned(struct page *page) { return false; }
2224 #endif
2225 
2226 #ifdef CONFIG_DEBUG_PAGEALLOC
2227 extern bool _debug_pagealloc_enabled;
2228 extern void __kernel_map_pages(struct page *page, int numpages, int enable);
2229 
2230 static inline bool debug_pagealloc_enabled(void)
2231 {
2232         return _debug_pagealloc_enabled;
2233 }
2234 
2235 static inline void
2236 kernel_map_pages(struct page *page, int numpages, int enable)
2237 {
2238         if (!debug_pagealloc_enabled())
2239                 return;
2240 
2241         __kernel_map_pages(page, numpages, enable);
2242 }
2243 #ifdef CONFIG_HIBERNATION
2244 extern bool kernel_page_present(struct page *page);
2245 #endif  /* CONFIG_HIBERNATION */
2246 #else   /* CONFIG_DEBUG_PAGEALLOC */
2247 static inline void
2248 kernel_map_pages(struct page *page, int numpages, int enable) {}
2249 #ifdef CONFIG_HIBERNATION
2250 static inline bool kernel_page_present(struct page *page) { return true; }
2251 #endif  /* CONFIG_HIBERNATION */
2252 static inline bool debug_pagealloc_enabled(void)
2253 {
2254         return false;
2255 }
2256 #endif  /* CONFIG_DEBUG_PAGEALLOC */
2257 
2258 #ifdef __HAVE_ARCH_GATE_AREA
2259 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
2260 extern int in_gate_area_no_mm(unsigned long addr);
2261 extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
2262 #else
2263 static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
2264 {
2265         return NULL;
2266 }
2267 static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
2268 static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
2269 {
2270         return 0;
2271 }
2272 #endif  /* __HAVE_ARCH_GATE_AREA */
2273 
2274 #ifdef CONFIG_SYSCTL
2275 extern int sysctl_drop_caches;
2276 int drop_caches_sysctl_handler(struct ctl_table *, int,
2277                                         void __user *, size_t *, loff_t *);
2278 #endif
2279 
2280 void drop_slab(void);
2281 void drop_slab_node(int nid);
2282 
2283 #ifndef CONFIG_MMU
2284 #define randomize_va_space 0
2285 #else
2286 extern int randomize_va_space;
2287 #endif
2288 
2289 const char * arch_vma_name(struct vm_area_struct *vma);
2290 void print_vma_addr(char *prefix, unsigned long rip);
2291 
2292 void sparse_mem_maps_populate_node(struct page **map_map,
2293                                    unsigned long pnum_begin,
2294                                    unsigned long pnum_end,
2295                                    unsigned long map_count,
2296                                    int nodeid);
2297 
2298 struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
2299 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
2300 pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
2301 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
2302 pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
2303 void *vmemmap_alloc_block(unsigned long size, int node);
2304 struct vmem_altmap;
2305 void *__vmemmap_alloc_block_buf(unsigned long size, int node,
2306                 struct vmem_altmap *altmap);
2307 static inline void *vmemmap_alloc_block_buf(unsigned long size, int node)
2308 {
2309         return __vmemmap_alloc_block_buf(size, node, NULL);
2310 }
2311 
2312 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
2313 int vmemmap_populate_basepages(unsigned long start, unsigned long end,
2314                                int node);
2315 int vmemmap_populate(unsigned long start, unsigned long end, int node);
2316 void vmemmap_populate_print_last(void);
2317 #ifdef CONFIG_MEMORY_HOTPLUG
2318 void vmemmap_free(unsigned long start, unsigned long end);
2319 #endif
2320 void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
2321                                   unsigned long size);
2322 
2323 enum mf_flags {
2324         MF_COUNT_INCREASED = 1 << 0,
2325         MF_ACTION_REQUIRED = 1 << 1,
2326         MF_MUST_KILL = 1 << 2,
2327         MF_SOFT_OFFLINE = 1 << 3,
2328 };
2329 extern int memory_failure(unsigned long pfn, int trapno, int flags);
2330 extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
2331 extern int unpoison_memory(unsigned long pfn);
2332 extern int get_hwpoison_page(struct page *page);
2333 #define put_hwpoison_page(page) put_page(page)
2334 extern int sysctl_memory_failure_early_kill;
2335 extern int sysctl_memory_failure_recovery;
2336 extern void shake_page(struct page *p, int access);
2337 extern atomic_long_t num_poisoned_pages;
2338 extern int soft_offline_page(struct page *page, int flags);
2339 
2340 
2341 /*
2342  * Error handlers for various types of pages.
2343  */
2344 enum mf_result {
2345         MF_IGNORED,     /* Error: cannot be handled */
2346         MF_FAILED,      /* Error: handling failed */
2347         MF_DELAYED,     /* Will be handled later */
2348         MF_RECOVERED,   /* Successfully recovered */
2349 };
2350 
2351 enum mf_action_page_type {
2352         MF_MSG_KERNEL,
2353         MF_MSG_KERNEL_HIGH_ORDER,
2354         MF_MSG_SLAB,
2355         MF_MSG_DIFFERENT_COMPOUND,
2356         MF_MSG_POISONED_HUGE,
2357         MF_MSG_HUGE,
2358         MF_MSG_FREE_HUGE,
2359         MF_MSG_UNMAP_FAILED,
2360         MF_MSG_DIRTY_SWAPCACHE,
2361         MF_MSG_CLEAN_SWAPCACHE,
2362         MF_MSG_DIRTY_MLOCKED_LRU,
2363         MF_MSG_CLEAN_MLOCKED_LRU,
2364         MF_MSG_DIRTY_UNEVICTABLE_LRU,
2365         MF_MSG_CLEAN_UNEVICTABLE_LRU,
2366         MF_MSG_DIRTY_LRU,
2367         MF_MSG_CLEAN_LRU,
2368         MF_MSG_TRUNCATED_LRU,
2369         MF_MSG_BUDDY,
2370         MF_MSG_BUDDY_2ND,
2371         MF_MSG_UNKNOWN,
2372 };
2373 
2374 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
2375 extern void clear_huge_page(struct page *page,
2376                             unsigned long addr,
2377                             unsigned int pages_per_huge_page);
2378 extern void copy_user_huge_page(struct page *dst, struct page *src,
2379                                 unsigned long addr, struct vm_area_struct *vma,
2380                                 unsigned int pages_per_huge_page);
2381 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
2382 
2383 extern struct page_ext_operations debug_guardpage_ops;
2384 extern struct page_ext_operations page_poisoning_ops;
2385 
2386 #ifdef CONFIG_DEBUG_PAGEALLOC
2387 extern unsigned int _debug_guardpage_minorder;
2388 extern bool _debug_guardpage_enabled;
2389 
2390 static inline unsigned int debug_guardpage_minorder(void)
2391 {
2392         return _debug_guardpage_minorder;
2393 }
2394 
2395 static inline bool debug_guardpage_enabled(void)
2396 {
2397         return _debug_guardpage_enabled;
2398 }
2399 
2400 static inline bool page_is_guard(struct page *page)
2401 {
2402         struct page_ext *page_ext;
2403 
2404         if (!debug_guardpage_enabled())
2405                 return false;
2406 
2407         page_ext = lookup_page_ext(page);
2408         return test_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
2409 }
2410 #else
2411 static inline unsigned int debug_guardpage_minorder(void) { return 0; }
2412 static inline bool debug_guardpage_enabled(void) { return false; }
2413 static inline bool page_is_guard(struct page *page) { return false; }
2414 #endif /* CONFIG_DEBUG_PAGEALLOC */
2415 
2416 #if MAX_NUMNODES > 1
2417 void __init setup_nr_node_ids(void);
2418 #else
2419 static inline void setup_nr_node_ids(void) {}
2420 #endif
2421 
2422 #endif /* __KERNEL__ */
2423 #endif /* _LINUX_MM_H */
2424 

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