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

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef _LINUX_MM_H
  3 #define _LINUX_MM_H
  4 
  5 #include <linux/errno.h>
  6 
  7 #ifdef __KERNEL__
  8 
  9 #include <linux/mmdebug.h>
 10 #include <linux/gfp.h>
 11 #include <linux/bug.h>
 12 #include <linux/list.h>
 13 #include <linux/mmzone.h>
 14 #include <linux/rbtree.h>
 15 #include <linux/atomic.h>
 16 #include <linux/debug_locks.h>
 17 #include <linux/mm_types.h>
 18 #include <linux/range.h>
 19 #include <linux/pfn.h>
 20 #include <linux/percpu-refcount.h>
 21 #include <linux/bit_spinlock.h>
 22 #include <linux/shrinker.h>
 23 #include <linux/resource.h>
 24 #include <linux/page_ext.h>
 25 #include <linux/err.h>
 26 #include <linux/page_ref.h>
 27 #include <linux/memremap.h>
 28 
 29 struct mempolicy;
 30 struct anon_vma;
 31 struct anon_vma_chain;
 32 struct file_ra_state;
 33 struct user_struct;
 34 struct writeback_control;
 35 struct bdi_writeback;
 36 
 37 void init_mm_internals(void);
 38 
 39 #ifndef CONFIG_NEED_MULTIPLE_NODES      /* Don't use mapnrs, do it properly */
 40 extern unsigned long max_mapnr;
 41 
 42 static inline void set_max_mapnr(unsigned long limit)
 43 {
 44         max_mapnr = limit;
 45 }
 46 #else
 47 static inline void set_max_mapnr(unsigned long limit) { }
 48 #endif
 49 
 50 extern unsigned long totalram_pages;
 51 extern void * high_memory;
 52 extern int page_cluster;
 53 
 54 #ifdef CONFIG_SYSCTL
 55 extern int sysctl_legacy_va_layout;
 56 #else
 57 #define sysctl_legacy_va_layout 0
 58 #endif
 59 
 60 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
 61 extern const int mmap_rnd_bits_min;
 62 extern const int mmap_rnd_bits_max;
 63 extern int mmap_rnd_bits __read_mostly;
 64 #endif
 65 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
 66 extern const int mmap_rnd_compat_bits_min;
 67 extern const int mmap_rnd_compat_bits_max;
 68 extern int mmap_rnd_compat_bits __read_mostly;
 69 #endif
 70 
 71 #include <asm/page.h>
 72 #include <asm/pgtable.h>
 73 #include <asm/processor.h>
 74 
 75 #ifndef __pa_symbol
 76 #define __pa_symbol(x)  __pa(RELOC_HIDE((unsigned long)(x), 0))
 77 #endif
 78 
 79 #ifndef page_to_virt
 80 #define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x)))
 81 #endif
 82 
 83 #ifndef lm_alias
 84 #define lm_alias(x)     __va(__pa_symbol(x))
 85 #endif
 86 
 87 /*
 88  * To prevent common memory management code establishing
 89  * a zero page mapping on a read fault.
 90  * This macro should be defined within <asm/pgtable.h>.
 91  * s390 does this to prevent multiplexing of hardware bits
 92  * related to the physical page in case of virtualization.
 93  */
 94 #ifndef mm_forbids_zeropage
 95 #define mm_forbids_zeropage(X)  (0)
 96 #endif
 97 
 98 /*
 99  * On some architectures it is expensive to call memset() for small sizes.
100  * Those architectures should provide their own implementation of "struct page"
101  * zeroing by defining this macro in <asm/pgtable.h>.
102  */
103 #ifndef mm_zero_struct_page
104 #define mm_zero_struct_page(pp)  ((void)memset((pp), 0, sizeof(struct page)))
105 #endif
106 
107 /*
108  * Default maximum number of active map areas, this limits the number of vmas
109  * per mm struct. Users can overwrite this number by sysctl but there is a
110  * problem.
111  *
112  * When a program's coredump is generated as ELF format, a section is created
113  * per a vma. In ELF, the number of sections is represented in unsigned short.
114  * This means the number of sections should be smaller than 65535 at coredump.
115  * Because the kernel adds some informative sections to a image of program at
116  * generating coredump, we need some margin. The number of extra sections is
117  * 1-3 now and depends on arch. We use "5" as safe margin, here.
118  *
119  * ELF extended numbering allows more than 65535 sections, so 16-bit bound is
120  * not a hard limit any more. Although some userspace tools can be surprised by
121  * that.
122  */
123 #define MAPCOUNT_ELF_CORE_MARGIN        (5)
124 #define DEFAULT_MAX_MAP_COUNT   (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)
125 
126 extern int sysctl_max_map_count;
127 
128 extern unsigned long sysctl_user_reserve_kbytes;
129 extern unsigned long sysctl_admin_reserve_kbytes;
130 
131 extern int sysctl_overcommit_memory;
132 extern int sysctl_overcommit_ratio;
133 extern unsigned long sysctl_overcommit_kbytes;
134 
135 extern int overcommit_ratio_handler(struct ctl_table *, int, void __user *,
136                                     size_t *, loff_t *);
137 extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
138                                     size_t *, loff_t *);
139 
140 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
141 
142 /* to align the pointer to the (next) page boundary */
143 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
144 
145 /* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
146 #define PAGE_ALIGNED(addr)      IS_ALIGNED((unsigned long)(addr), PAGE_SIZE)
147 
148 /*
149  * Linux kernel virtual memory manager primitives.
150  * The idea being to have a "virtual" mm in the same way
151  * we have a virtual fs - giving a cleaner interface to the
152  * mm details, and allowing different kinds of memory mappings
153  * (from shared memory to executable loading to arbitrary
154  * mmap() functions).
155  */
156 
157 extern struct kmem_cache *vm_area_cachep;
158 
159 #ifndef CONFIG_MMU
160 extern struct rb_root nommu_region_tree;
161 extern struct rw_semaphore nommu_region_sem;
162 
163 extern unsigned int kobjsize(const void *objp);
164 #endif
165 
166 /*
167  * vm_flags in vm_area_struct, see mm_types.h.
168  * When changing, update also include/trace/events/mmflags.h
169  */
170 #define VM_NONE         0x00000000
171 
172 #define VM_READ         0x00000001      /* currently active flags */
173 #define VM_WRITE        0x00000002
174 #define VM_EXEC         0x00000004
175 #define VM_SHARED       0x00000008
176 
177 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
178 #define VM_MAYREAD      0x00000010      /* limits for mprotect() etc */
179 #define VM_MAYWRITE     0x00000020
180 #define VM_MAYEXEC      0x00000040
181 #define VM_MAYSHARE     0x00000080
182 
183 #define VM_GROWSDOWN    0x00000100      /* general info on the segment */
184 #define VM_UFFD_MISSING 0x00000200      /* missing pages tracking */
185 #define VM_PFNMAP       0x00000400      /* Page-ranges managed without "struct page", just pure PFN */
186 #define VM_DENYWRITE    0x00000800      /* ETXTBSY on write attempts.. */
187 #define VM_UFFD_WP      0x00001000      /* wrprotect pages tracking */
188 
189 #define VM_LOCKED       0x00002000
190 #define VM_IO           0x00004000      /* Memory mapped I/O or similar */
191 
192                                         /* Used by sys_madvise() */
193 #define VM_SEQ_READ     0x00008000      /* App will access data sequentially */
194 #define VM_RAND_READ    0x00010000      /* App will not benefit from clustered reads */
195 
196 #define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
197 #define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
198 #define VM_LOCKONFAULT  0x00080000      /* Lock the pages covered when they are faulted in */
199 #define VM_ACCOUNT      0x00100000      /* Is a VM accounted object */
200 #define VM_NORESERVE    0x00200000      /* should the VM suppress accounting */
201 #define VM_HUGETLB      0x00400000      /* Huge TLB Page VM */
202 #define VM_SYNC         0x00800000      /* Synchronous page faults */
203 #define VM_ARCH_1       0x01000000      /* Architecture-specific flag */
204 #define VM_WIPEONFORK   0x02000000      /* Wipe VMA contents in child. */
205 #define VM_DONTDUMP     0x04000000      /* Do not include in the core dump */
206 
207 #ifdef CONFIG_MEM_SOFT_DIRTY
208 # define VM_SOFTDIRTY   0x08000000      /* Not soft dirty clean area */
209 #else
210 # define VM_SOFTDIRTY   0
211 #endif
212 
213 #define VM_MIXEDMAP     0x10000000      /* Can contain "struct page" and pure PFN pages */
214 #define VM_HUGEPAGE     0x20000000      /* MADV_HUGEPAGE marked this vma */
215 #define VM_NOHUGEPAGE   0x40000000      /* MADV_NOHUGEPAGE marked this vma */
216 #define VM_MERGEABLE    0x80000000      /* KSM may merge identical pages */
217 
218 #ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
219 #define VM_HIGH_ARCH_BIT_0      32      /* bit only usable on 64-bit architectures */
220 #define VM_HIGH_ARCH_BIT_1      33      /* bit only usable on 64-bit architectures */
221 #define VM_HIGH_ARCH_BIT_2      34      /* bit only usable on 64-bit architectures */
222 #define VM_HIGH_ARCH_BIT_3      35      /* bit only usable on 64-bit architectures */
223 #define VM_HIGH_ARCH_BIT_4      36      /* bit only usable on 64-bit architectures */
224 #define VM_HIGH_ARCH_0  BIT(VM_HIGH_ARCH_BIT_0)
225 #define VM_HIGH_ARCH_1  BIT(VM_HIGH_ARCH_BIT_1)
226 #define VM_HIGH_ARCH_2  BIT(VM_HIGH_ARCH_BIT_2)
227 #define VM_HIGH_ARCH_3  BIT(VM_HIGH_ARCH_BIT_3)
228 #define VM_HIGH_ARCH_4  BIT(VM_HIGH_ARCH_BIT_4)
229 #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
230 
231 #if defined(CONFIG_X86)
232 # define VM_PAT         VM_ARCH_1       /* PAT reserves whole VMA at once (x86) */
233 #if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)
234 # define VM_PKEY_SHIFT  VM_HIGH_ARCH_BIT_0
235 # define VM_PKEY_BIT0   VM_HIGH_ARCH_0  /* A protection key is a 4-bit value */
236 # define VM_PKEY_BIT1   VM_HIGH_ARCH_1
237 # define VM_PKEY_BIT2   VM_HIGH_ARCH_2
238 # define VM_PKEY_BIT3   VM_HIGH_ARCH_3
239 #endif
240 #elif defined(CONFIG_PPC)
241 # define VM_SAO         VM_ARCH_1       /* Strong Access Ordering (powerpc) */
242 #elif defined(CONFIG_PARISC)
243 # define VM_GROWSUP     VM_ARCH_1
244 #elif defined(CONFIG_METAG)
245 # define VM_GROWSUP     VM_ARCH_1
246 #elif defined(CONFIG_IA64)
247 # define VM_GROWSUP     VM_ARCH_1
248 #elif !defined(CONFIG_MMU)
249 # define VM_MAPPED_COPY VM_ARCH_1       /* T if mapped copy of data (nommu mmap) */
250 #endif
251 
252 #if defined(CONFIG_X86_INTEL_MPX)
253 /* MPX specific bounds table or bounds directory */
254 # define VM_MPX         VM_HIGH_ARCH_4
255 #else
256 # define VM_MPX         VM_NONE
257 #endif
258 
259 #ifndef VM_GROWSUP
260 # define VM_GROWSUP     VM_NONE
261 #endif
262 
263 /* Bits set in the VMA until the stack is in its final location */
264 #define VM_STACK_INCOMPLETE_SETUP       (VM_RAND_READ | VM_SEQ_READ)
265 
266 #ifndef VM_STACK_DEFAULT_FLAGS          /* arch can override this */
267 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
268 #endif
269 
270 #ifdef CONFIG_STACK_GROWSUP
271 #define VM_STACK        VM_GROWSUP
272 #else
273 #define VM_STACK        VM_GROWSDOWN
274 #endif
275 
276 #define VM_STACK_FLAGS  (VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
277 
278 /*
279  * Special vmas that are non-mergable, non-mlock()able.
280  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
281  */
282 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
283 
284 /* This mask defines which mm->def_flags a process can inherit its parent */
285 #define VM_INIT_DEF_MASK        VM_NOHUGEPAGE
286 
287 /* This mask is used to clear all the VMA flags used by mlock */
288 #define VM_LOCKED_CLEAR_MASK    (~(VM_LOCKED | VM_LOCKONFAULT))
289 
290 /*
291  * mapping from the currently active vm_flags protection bits (the
292  * low four bits) to a page protection mask..
293  */
294 extern pgprot_t protection_map[16];
295 
296 #define FAULT_FLAG_WRITE        0x01    /* Fault was a write access */
297 #define FAULT_FLAG_MKWRITE      0x02    /* Fault was mkwrite of existing pte */
298 #define FAULT_FLAG_ALLOW_RETRY  0x04    /* Retry fault if blocking */
299 #define FAULT_FLAG_RETRY_NOWAIT 0x08    /* Don't drop mmap_sem and wait when retrying */
300 #define FAULT_FLAG_KILLABLE     0x10    /* The fault task is in SIGKILL killable region */
301 #define FAULT_FLAG_TRIED        0x20    /* Second try */
302 #define FAULT_FLAG_USER         0x40    /* The fault originated in userspace */
303 #define FAULT_FLAG_REMOTE       0x80    /* faulting for non current tsk/mm */
304 #define FAULT_FLAG_INSTRUCTION  0x100   /* The fault was during an instruction fetch */
305 
306 #define FAULT_FLAG_TRACE \
307         { FAULT_FLAG_WRITE,             "WRITE" }, \
308         { FAULT_FLAG_MKWRITE,           "MKWRITE" }, \
309         { FAULT_FLAG_ALLOW_RETRY,       "ALLOW_RETRY" }, \
310         { FAULT_FLAG_RETRY_NOWAIT,      "RETRY_NOWAIT" }, \
311         { FAULT_FLAG_KILLABLE,          "KILLABLE" }, \
312         { FAULT_FLAG_TRIED,             "TRIED" }, \
313         { FAULT_FLAG_USER,              "USER" }, \
314         { FAULT_FLAG_REMOTE,            "REMOTE" }, \
315         { FAULT_FLAG_INSTRUCTION,       "INSTRUCTION" }
316 
317 /*
318  * vm_fault is filled by the the pagefault handler and passed to the vma's
319  * ->fault function. The vma's ->fault is responsible for returning a bitmask
320  * of VM_FAULT_xxx flags that give details about how the fault was handled.
321  *
322  * MM layer fills up gfp_mask for page allocations but fault handler might
323  * alter it if its implementation requires a different allocation context.
324  *
325  * pgoff should be used in favour of virtual_address, if possible.
326  */
327 struct vm_fault {
328         struct vm_area_struct *vma;     /* Target VMA */
329         unsigned int flags;             /* FAULT_FLAG_xxx flags */
330         gfp_t gfp_mask;                 /* gfp mask to be used for allocations */
331         pgoff_t pgoff;                  /* Logical page offset based on vma */
332         unsigned long address;          /* Faulting virtual address */
333         pmd_t *pmd;                     /* Pointer to pmd entry matching
334                                          * the 'address' */
335         pud_t *pud;                     /* Pointer to pud entry matching
336                                          * the 'address'
337                                          */
338         pte_t orig_pte;                 /* Value of PTE at the time of fault */
339 
340         struct page *cow_page;          /* Page handler may use for COW fault */
341         struct mem_cgroup *memcg;       /* Cgroup cow_page belongs to */
342         struct page *page;              /* ->fault handlers should return a
343                                          * page here, unless VM_FAULT_NOPAGE
344                                          * is set (which is also implied by
345                                          * VM_FAULT_ERROR).
346                                          */
347         /* These three entries are valid only while holding ptl lock */
348         pte_t *pte;                     /* Pointer to pte entry matching
349                                          * the 'address'. NULL if the page
350                                          * table hasn't been allocated.
351                                          */
352         spinlock_t *ptl;                /* Page table lock.
353                                          * Protects pte page table if 'pte'
354                                          * is not NULL, otherwise pmd.
355                                          */
356         pgtable_t prealloc_pte;         /* Pre-allocated pte page table.
357                                          * vm_ops->map_pages() calls
358                                          * alloc_set_pte() from atomic context.
359                                          * do_fault_around() pre-allocates
360                                          * page table to avoid allocation from
361                                          * atomic context.
362                                          */
363 };
364 
365 /* page entry size for vm->huge_fault() */
366 enum page_entry_size {
367         PE_SIZE_PTE = 0,
368         PE_SIZE_PMD,
369         PE_SIZE_PUD,
370 };
371 
372 /*
373  * These are the virtual MM functions - opening of an area, closing and
374  * unmapping it (needed to keep files on disk up-to-date etc), pointer
375  * to the functions called when a no-page or a wp-page exception occurs. 
376  */
377 struct vm_operations_struct {
378         void (*open)(struct vm_area_struct * area);
379         void (*close)(struct vm_area_struct * area);
380         int (*split)(struct vm_area_struct * area, unsigned long addr);
381         int (*mremap)(struct vm_area_struct * area);
382         int (*fault)(struct vm_fault *vmf);
383         int (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size);
384         void (*map_pages)(struct vm_fault *vmf,
385                         pgoff_t start_pgoff, pgoff_t end_pgoff);
386 
387         /* notification that a previously read-only page is about to become
388          * writable, if an error is returned it will cause a SIGBUS */
389         int (*page_mkwrite)(struct vm_fault *vmf);
390 
391         /* same as page_mkwrite when using VM_PFNMAP|VM_MIXEDMAP */
392         int (*pfn_mkwrite)(struct vm_fault *vmf);
393 
394         /* called by access_process_vm when get_user_pages() fails, typically
395          * for use by special VMAs that can switch between memory and hardware
396          */
397         int (*access)(struct vm_area_struct *vma, unsigned long addr,
398                       void *buf, int len, int write);
399 
400         /* Called by the /proc/PID/maps code to ask the vma whether it
401          * has a special name.  Returning non-NULL will also cause this
402          * vma to be dumped unconditionally. */
403         const char *(*name)(struct vm_area_struct *vma);
404 
405 #ifdef CONFIG_NUMA
406         /*
407          * set_policy() op must add a reference to any non-NULL @new mempolicy
408          * to hold the policy upon return.  Caller should pass NULL @new to
409          * remove a policy and fall back to surrounding context--i.e. do not
410          * install a MPOL_DEFAULT policy, nor the task or system default
411          * mempolicy.
412          */
413         int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
414 
415         /*
416          * get_policy() op must add reference [mpol_get()] to any policy at
417          * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
418          * in mm/mempolicy.c will do this automatically.
419          * get_policy() must NOT add a ref if the policy at (vma,addr) is not
420          * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
421          * If no [shared/vma] mempolicy exists at the addr, get_policy() op
422          * must return NULL--i.e., do not "fallback" to task or system default
423          * policy.
424          */
425         struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
426                                         unsigned long addr);
427 #endif
428         /*
429          * Called by vm_normal_page() for special PTEs to find the
430          * page for @addr.  This is useful if the default behavior
431          * (using pte_page()) would not find the correct page.
432          */
433         struct page *(*find_special_page)(struct vm_area_struct *vma,
434                                           unsigned long addr);
435 };
436 
437 struct mmu_gather;
438 struct inode;
439 
440 #define page_private(page)              ((page)->private)
441 #define set_page_private(page, v)       ((page)->private = (v))
442 
443 #if !defined(__HAVE_ARCH_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
444 static inline int pmd_devmap(pmd_t pmd)
445 {
446         return 0;
447 }
448 static inline int pud_devmap(pud_t pud)
449 {
450         return 0;
451 }
452 static inline int pgd_devmap(pgd_t pgd)
453 {
454         return 0;
455 }
456 #endif
457 
458 /*
459  * FIXME: take this include out, include page-flags.h in
460  * files which need it (119 of them)
461  */
462 #include <linux/page-flags.h>
463 #include <linux/huge_mm.h>
464 
465 /*
466  * Methods to modify the page usage count.
467  *
468  * What counts for a page usage:
469  * - cache mapping   (page->mapping)
470  * - private data    (page->private)
471  * - page mapped in a task's page tables, each mapping
472  *   is counted separately
473  *
474  * Also, many kernel routines increase the page count before a critical
475  * routine so they can be sure the page doesn't go away from under them.
476  */
477 
478 /*
479  * Drop a ref, return true if the refcount fell to zero (the page has no users)
480  */
481 static inline int put_page_testzero(struct page *page)
482 {
483         VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
484         return page_ref_dec_and_test(page);
485 }
486 
487 /*
488  * Try to grab a ref unless the page has a refcount of zero, return false if
489  * that is the case.
490  * This can be called when MMU is off so it must not access
491  * any of the virtual mappings.
492  */
493 static inline int get_page_unless_zero(struct page *page)
494 {
495         return page_ref_add_unless(page, 1, 0);
496 }
497 
498 extern int page_is_ram(unsigned long pfn);
499 
500 enum {
501         REGION_INTERSECTS,
502         REGION_DISJOINT,
503         REGION_MIXED,
504 };
505 
506 int region_intersects(resource_size_t offset, size_t size, unsigned long flags,
507                       unsigned long desc);
508 
509 /* Support for virtually mapped pages */
510 struct page *vmalloc_to_page(const void *addr);
511 unsigned long vmalloc_to_pfn(const void *addr);
512 
513 /*
514  * Determine if an address is within the vmalloc range
515  *
516  * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
517  * is no special casing required.
518  */
519 static inline bool is_vmalloc_addr(const void *x)
520 {
521 #ifdef CONFIG_MMU
522         unsigned long addr = (unsigned long)x;
523 
524         return addr >= VMALLOC_START && addr < VMALLOC_END;
525 #else
526         return false;
527 #endif
528 }
529 #ifdef CONFIG_MMU
530 extern int is_vmalloc_or_module_addr(const void *x);
531 #else
532 static inline int is_vmalloc_or_module_addr(const void *x)
533 {
534         return 0;
535 }
536 #endif
537 
538 extern void *kvmalloc_node(size_t size, gfp_t flags, int node);
539 static inline void *kvmalloc(size_t size, gfp_t flags)
540 {
541         return kvmalloc_node(size, flags, NUMA_NO_NODE);
542 }
543 static inline void *kvzalloc_node(size_t size, gfp_t flags, int node)
544 {
545         return kvmalloc_node(size, flags | __GFP_ZERO, node);
546 }
547 static inline void *kvzalloc(size_t size, gfp_t flags)
548 {
549         return kvmalloc(size, flags | __GFP_ZERO);
550 }
551 
552 static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
553 {
554         if (size != 0 && n > SIZE_MAX / size)
555                 return NULL;
556 
557         return kvmalloc(n * size, flags);
558 }
559 
560 extern void kvfree(const void *addr);
561 
562 static inline atomic_t *compound_mapcount_ptr(struct page *page)
563 {
564         return &page[1].compound_mapcount;
565 }
566 
567 static inline int compound_mapcount(struct page *page)
568 {
569         VM_BUG_ON_PAGE(!PageCompound(page), page);
570         page = compound_head(page);
571         return atomic_read(compound_mapcount_ptr(page)) + 1;
572 }
573 
574 /*
575  * The atomic page->_mapcount, starts from -1: so that transitions
576  * both from it and to it can be tracked, using atomic_inc_and_test
577  * and atomic_add_negative(-1).
578  */
579 static inline void page_mapcount_reset(struct page *page)
580 {
581         atomic_set(&(page)->_mapcount, -1);
582 }
583 
584 int __page_mapcount(struct page *page);
585 
586 static inline int page_mapcount(struct page *page)
587 {
588         VM_BUG_ON_PAGE(PageSlab(page), page);
589 
590         if (unlikely(PageCompound(page)))
591                 return __page_mapcount(page);
592         return atomic_read(&page->_mapcount) + 1;
593 }
594 
595 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
596 int total_mapcount(struct page *page);
597 int page_trans_huge_mapcount(struct page *page, int *total_mapcount);
598 #else
599 static inline int total_mapcount(struct page *page)
600 {
601         return page_mapcount(page);
602 }
603 static inline int page_trans_huge_mapcount(struct page *page,
604                                            int *total_mapcount)
605 {
606         int mapcount = page_mapcount(page);
607         if (total_mapcount)
608                 *total_mapcount = mapcount;
609         return mapcount;
610 }
611 #endif
612 
613 static inline struct page *virt_to_head_page(const void *x)
614 {
615         struct page *page = virt_to_page(x);
616 
617         return compound_head(page);
618 }
619 
620 void __put_page(struct page *page);
621 
622 void put_pages_list(struct list_head *pages);
623 
624 void split_page(struct page *page, unsigned int order);
625 
626 /*
627  * Compound pages have a destructor function.  Provide a
628  * prototype for that function and accessor functions.
629  * These are _only_ valid on the head of a compound page.
630  */
631 typedef void compound_page_dtor(struct page *);
632 
633 /* Keep the enum in sync with compound_page_dtors array in mm/page_alloc.c */
634 enum compound_dtor_id {
635         NULL_COMPOUND_DTOR,
636         COMPOUND_PAGE_DTOR,
637 #ifdef CONFIG_HUGETLB_PAGE
638         HUGETLB_PAGE_DTOR,
639 #endif
640 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
641         TRANSHUGE_PAGE_DTOR,
642 #endif
643         NR_COMPOUND_DTORS,
644 };
645 extern compound_page_dtor * const compound_page_dtors[];
646 
647 static inline void set_compound_page_dtor(struct page *page,
648                 enum compound_dtor_id compound_dtor)
649 {
650         VM_BUG_ON_PAGE(compound_dtor >= NR_COMPOUND_DTORS, page);
651         page[1].compound_dtor = compound_dtor;
652 }
653 
654 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
655 {
656         VM_BUG_ON_PAGE(page[1].compound_dtor >= NR_COMPOUND_DTORS, page);
657         return compound_page_dtors[page[1].compound_dtor];
658 }
659 
660 static inline unsigned int compound_order(struct page *page)
661 {
662         if (!PageHead(page))
663                 return 0;
664         return page[1].compound_order;
665 }
666 
667 static inline void set_compound_order(struct page *page, unsigned int order)
668 {
669         page[1].compound_order = order;
670 }
671 
672 void free_compound_page(struct page *page);
673 
674 #ifdef CONFIG_MMU
675 /*
676  * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
677  * servicing faults for write access.  In the normal case, do always want
678  * pte_mkwrite.  But get_user_pages can cause write faults for mappings
679  * that do not have writing enabled, when used by access_process_vm.
680  */
681 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
682 {
683         if (likely(vma->vm_flags & VM_WRITE))
684                 pte = pte_mkwrite(pte);
685         return pte;
686 }
687 
688 int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
689                 struct page *page);
690 int finish_fault(struct vm_fault *vmf);
691 int finish_mkwrite_fault(struct vm_fault *vmf);
692 #endif
693 
694 /*
695  * Multiple processes may "see" the same page. E.g. for untouched
696  * mappings of /dev/null, all processes see the same page full of
697  * zeroes, and text pages of executables and shared libraries have
698  * only one copy in memory, at most, normally.
699  *
700  * For the non-reserved pages, page_count(page) denotes a reference count.
701  *   page_count() == 0 means the page is free. page->lru is then used for
702  *   freelist management in the buddy allocator.
703  *   page_count() > 0  means the page has been allocated.
704  *
705  * Pages are allocated by the slab allocator in order to provide memory
706  * to kmalloc and kmem_cache_alloc. In this case, the management of the
707  * page, and the fields in 'struct page' are the responsibility of mm/slab.c
708  * unless a particular usage is carefully commented. (the responsibility of
709  * freeing the kmalloc memory is the caller's, of course).
710  *
711  * A page may be used by anyone else who does a __get_free_page().
712  * In this case, page_count still tracks the references, and should only
713  * be used through the normal accessor functions. The top bits of page->flags
714  * and page->virtual store page management information, but all other fields
715  * are unused and could be used privately, carefully. The management of this
716  * page is the responsibility of the one who allocated it, and those who have
717  * subsequently been given references to it.
718  *
719  * The other pages (we may call them "pagecache pages") are completely
720  * managed by the Linux memory manager: I/O, buffers, swapping etc.
721  * The following discussion applies only to them.
722  *
723  * A pagecache page contains an opaque `private' member, which belongs to the
724  * page's address_space. Usually, this is the address of a circular list of
725  * the page's disk buffers. PG_private must be set to tell the VM to call
726  * into the filesystem to release these pages.
727  *
728  * A page may belong to an inode's memory mapping. In this case, page->mapping
729  * is the pointer to the inode, and page->index is the file offset of the page,
730  * in units of PAGE_SIZE.
731  *
732  * If pagecache pages are not associated with an inode, they are said to be
733  * anonymous pages. These may become associated with the swapcache, and in that
734  * case PG_swapcache is set, and page->private is an offset into the swapcache.
735  *
736  * In either case (swapcache or inode backed), the pagecache itself holds one
737  * reference to the page. Setting PG_private should also increment the
738  * refcount. The each user mapping also has a reference to the page.
739  *
740  * The pagecache pages are stored in a per-mapping radix tree, which is
741  * rooted at mapping->page_tree, and indexed by offset.
742  * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
743  * lists, we instead now tag pages as dirty/writeback in the radix tree.
744  *
745  * All pagecache pages may be subject to I/O:
746  * - inode pages may need to be read from disk,
747  * - inode pages which have been modified and are MAP_SHARED may need
748  *   to be written back to the inode on disk,
749  * - anonymous pages (including MAP_PRIVATE file mappings) which have been
750  *   modified may need to be swapped out to swap space and (later) to be read
751  *   back into memory.
752  */
753 
754 /*
755  * The zone field is never updated after free_area_init_core()
756  * sets it, so none of the operations on it need to be atomic.
757  */
758 
759 /* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
760 #define SECTIONS_PGOFF          ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
761 #define NODES_PGOFF             (SECTIONS_PGOFF - NODES_WIDTH)
762 #define ZONES_PGOFF             (NODES_PGOFF - ZONES_WIDTH)
763 #define LAST_CPUPID_PGOFF       (ZONES_PGOFF - LAST_CPUPID_WIDTH)
764 
765 /*
766  * Define the bit shifts to access each section.  For non-existent
767  * sections we define the shift as 0; that plus a 0 mask ensures
768  * the compiler will optimise away reference to them.
769  */
770 #define SECTIONS_PGSHIFT        (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
771 #define NODES_PGSHIFT           (NODES_PGOFF * (NODES_WIDTH != 0))
772 #define ZONES_PGSHIFT           (ZONES_PGOFF * (ZONES_WIDTH != 0))
773 #define LAST_CPUPID_PGSHIFT     (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
774 
775 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
776 #ifdef NODE_NOT_IN_PAGE_FLAGS
777 #define ZONEID_SHIFT            (SECTIONS_SHIFT + ZONES_SHIFT)
778 #define ZONEID_PGOFF            ((SECTIONS_PGOFF < ZONES_PGOFF)? \
779                                                 SECTIONS_PGOFF : ZONES_PGOFF)
780 #else
781 #define ZONEID_SHIFT            (NODES_SHIFT + ZONES_SHIFT)
782 #define ZONEID_PGOFF            ((NODES_PGOFF < ZONES_PGOFF)? \
783                                                 NODES_PGOFF : ZONES_PGOFF)
784 #endif
785 
786 #define ZONEID_PGSHIFT          (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
787 
788 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
789 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
790 #endif
791 
792 #define ZONES_MASK              ((1UL << ZONES_WIDTH) - 1)
793 #define NODES_MASK              ((1UL << NODES_WIDTH) - 1)
794 #define SECTIONS_MASK           ((1UL << SECTIONS_WIDTH) - 1)
795 #define LAST_CPUPID_MASK        ((1UL << LAST_CPUPID_SHIFT) - 1)
796 #define ZONEID_MASK             ((1UL << ZONEID_SHIFT) - 1)
797 
798 static inline enum zone_type page_zonenum(const struct page *page)
799 {
800         return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
801 }
802 
803 #ifdef CONFIG_ZONE_DEVICE
804 static inline bool is_zone_device_page(const struct page *page)
805 {
806         return page_zonenum(page) == ZONE_DEVICE;
807 }
808 #else
809 static inline bool is_zone_device_page(const struct page *page)
810 {
811         return false;
812 }
813 #endif
814 
815 #if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
816 void put_zone_device_private_or_public_page(struct page *page);
817 DECLARE_STATIC_KEY_FALSE(device_private_key);
818 #define IS_HMM_ENABLED static_branch_unlikely(&device_private_key)
819 static inline bool is_device_private_page(const struct page *page);
820 static inline bool is_device_public_page(const struct page *page);
821 #else /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
822 static inline void put_zone_device_private_or_public_page(struct page *page)
823 {
824 }
825 #define IS_HMM_ENABLED 0
826 static inline bool is_device_private_page(const struct page *page)
827 {
828         return false;
829 }
830 static inline bool is_device_public_page(const struct page *page)
831 {
832         return false;
833 }
834 #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
835 
836 
837 static inline void get_page(struct page *page)
838 {
839         page = compound_head(page);
840         /*
841          * Getting a normal page or the head of a compound page
842          * requires to already have an elevated page->_refcount.
843          */
844         VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page);
845         page_ref_inc(page);
846 }
847 
848 static inline void put_page(struct page *page)
849 {
850         page = compound_head(page);
851 
852         /*
853          * For private device pages we need to catch refcount transition from
854          * 2 to 1, when refcount reach one it means the private device page is
855          * free and we need to inform the device driver through callback. See
856          * include/linux/memremap.h and HMM for details.
857          */
858         if (IS_HMM_ENABLED && unlikely(is_device_private_page(page) ||
859             unlikely(is_device_public_page(page)))) {
860                 put_zone_device_private_or_public_page(page);
861                 return;
862         }
863 
864         if (put_page_testzero(page))
865                 __put_page(page);
866 }
867 
868 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
869 #define SECTION_IN_PAGE_FLAGS
870 #endif
871 
872 /*
873  * The identification function is mainly used by the buddy allocator for
874  * determining if two pages could be buddies. We are not really identifying
875  * the zone since we could be using the section number id if we do not have
876  * node id available in page flags.
877  * We only guarantee that it will return the same value for two combinable
878  * pages in a zone.
879  */
880 static inline int page_zone_id(struct page *page)
881 {
882         return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
883 }
884 
885 static inline int zone_to_nid(struct zone *zone)
886 {
887 #ifdef CONFIG_NUMA
888         return zone->node;
889 #else
890         return 0;
891 #endif
892 }
893 
894 #ifdef NODE_NOT_IN_PAGE_FLAGS
895 extern int page_to_nid(const struct page *page);
896 #else
897 static inline int page_to_nid(const struct page *page)
898 {
899         return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
900 }
901 #endif
902 
903 #ifdef CONFIG_NUMA_BALANCING
904 static inline int cpu_pid_to_cpupid(int cpu, int pid)
905 {
906         return ((cpu & LAST__CPU_MASK) << LAST__PID_SHIFT) | (pid & LAST__PID_MASK);
907 }
908 
909 static inline int cpupid_to_pid(int cpupid)
910 {
911         return cpupid & LAST__PID_MASK;
912 }
913 
914 static inline int cpupid_to_cpu(int cpupid)
915 {
916         return (cpupid >> LAST__PID_SHIFT) & LAST__CPU_MASK;
917 }
918 
919 static inline int cpupid_to_nid(int cpupid)
920 {
921         return cpu_to_node(cpupid_to_cpu(cpupid));
922 }
923 
924 static inline bool cpupid_pid_unset(int cpupid)
925 {
926         return cpupid_to_pid(cpupid) == (-1 & LAST__PID_MASK);
927 }
928 
929 static inline bool cpupid_cpu_unset(int cpupid)
930 {
931         return cpupid_to_cpu(cpupid) == (-1 & LAST__CPU_MASK);
932 }
933 
934 static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
935 {
936         return (task_pid & LAST__PID_MASK) == cpupid_to_pid(cpupid);
937 }
938 
939 #define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
940 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
941 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
942 {
943         return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
944 }
945 
946 static inline int page_cpupid_last(struct page *page)
947 {
948         return page->_last_cpupid;
949 }
950 static inline void page_cpupid_reset_last(struct page *page)
951 {
952         page->_last_cpupid = -1 & LAST_CPUPID_MASK;
953 }
954 #else
955 static inline int page_cpupid_last(struct page *page)
956 {
957         return (page->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
958 }
959 
960 extern int page_cpupid_xchg_last(struct page *page, int cpupid);
961 
962 static inline void page_cpupid_reset_last(struct page *page)
963 {
964         page->flags |= LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT;
965 }
966 #endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
967 #else /* !CONFIG_NUMA_BALANCING */
968 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
969 {
970         return page_to_nid(page); /* XXX */
971 }
972 
973 static inline int page_cpupid_last(struct page *page)
974 {
975         return page_to_nid(page); /* XXX */
976 }
977 
978 static inline int cpupid_to_nid(int cpupid)
979 {
980         return -1;
981 }
982 
983 static inline int cpupid_to_pid(int cpupid)
984 {
985         return -1;
986 }
987 
988 static inline int cpupid_to_cpu(int cpupid)
989 {
990         return -1;
991 }
992 
993 static inline int cpu_pid_to_cpupid(int nid, int pid)
994 {
995         return -1;
996 }
997 
998 static inline bool cpupid_pid_unset(int cpupid)
999 {
1000         return 1;
1001 }
1002 
1003 static inline void page_cpupid_reset_last(struct page *page)
1004 {
1005 }
1006 
1007 static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
1008 {
1009         return false;
1010 }
1011 #endif /* CONFIG_NUMA_BALANCING */
1012 
1013 static inline struct zone *page_zone(const struct page *page)
1014 {
1015         return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
1016 }
1017 
1018 static inline pg_data_t *page_pgdat(const struct page *page)
1019 {
1020         return NODE_DATA(page_to_nid(page));
1021 }
1022 
1023 #ifdef SECTION_IN_PAGE_FLAGS
1024 static inline void set_page_section(struct page *page, unsigned long section)
1025 {
1026         page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
1027         page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
1028 }
1029 
1030 static inline unsigned long page_to_section(const struct page *page)
1031 {
1032         return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
1033 }
1034 #endif
1035 
1036 static inline void set_page_zone(struct page *page, enum zone_type zone)
1037 {
1038         page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
1039         page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
1040 }
1041 
1042 static inline void set_page_node(struct page *page, unsigned long node)
1043 {
1044         page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
1045         page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
1046 }
1047 
1048 static inline void set_page_links(struct page *page, enum zone_type zone,
1049         unsigned long node, unsigned long pfn)
1050 {
1051         set_page_zone(page, zone);
1052         set_page_node(page, node);
1053 #ifdef SECTION_IN_PAGE_FLAGS
1054         set_page_section(page, pfn_to_section_nr(pfn));
1055 #endif
1056 }
1057 
1058 #ifdef CONFIG_MEMCG
1059 static inline struct mem_cgroup *page_memcg(struct page *page)
1060 {
1061         return page->mem_cgroup;
1062 }
1063 static inline struct mem_cgroup *page_memcg_rcu(struct page *page)
1064 {
1065         WARN_ON_ONCE(!rcu_read_lock_held());
1066         return READ_ONCE(page->mem_cgroup);
1067 }
1068 #else
1069 static inline struct mem_cgroup *page_memcg(struct page *page)
1070 {
1071         return NULL;
1072 }
1073 static inline struct mem_cgroup *page_memcg_rcu(struct page *page)
1074 {
1075         WARN_ON_ONCE(!rcu_read_lock_held());
1076         return NULL;
1077 }
1078 #endif
1079 
1080 /*
1081  * Some inline functions in vmstat.h depend on page_zone()
1082  */
1083 #include <linux/vmstat.h>
1084 
1085 static __always_inline void *lowmem_page_address(const struct page *page)
1086 {
1087         return page_to_virt(page);
1088 }
1089 
1090 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
1091 #define HASHED_PAGE_VIRTUAL
1092 #endif
1093 
1094 #if defined(WANT_PAGE_VIRTUAL)
1095 static inline void *page_address(const struct page *page)
1096 {
1097         return page->virtual;
1098 }
1099 static inline void set_page_address(struct page *page, void *address)
1100 {
1101         page->virtual = address;
1102 }
1103 #define page_address_init()  do { } while(0)
1104 #endif
1105 
1106 #if defined(HASHED_PAGE_VIRTUAL)
1107 void *page_address(const struct page *page);
1108 void set_page_address(struct page *page, void *virtual);
1109 void page_address_init(void);
1110 #endif
1111 
1112 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
1113 #define page_address(page) lowmem_page_address(page)
1114 #define set_page_address(page, address)  do { } while(0)
1115 #define page_address_init()  do { } while(0)
1116 #endif
1117 
1118 extern void *page_rmapping(struct page *page);
1119 extern struct anon_vma *page_anon_vma(struct page *page);
1120 extern struct address_space *page_mapping(struct page *page);
1121 
1122 extern struct address_space *__page_file_mapping(struct page *);
1123 
1124 static inline
1125 struct address_space *page_file_mapping(struct page *page)
1126 {
1127         if (unlikely(PageSwapCache(page)))
1128                 return __page_file_mapping(page);
1129 
1130         return page->mapping;
1131 }
1132 
1133 extern pgoff_t __page_file_index(struct page *page);
1134 
1135 /*
1136  * Return the pagecache index of the passed page.  Regular pagecache pages
1137  * use ->index whereas swapcache pages use swp_offset(->private)
1138  */
1139 static inline pgoff_t page_index(struct page *page)
1140 {
1141         if (unlikely(PageSwapCache(page)))
1142                 return __page_file_index(page);
1143         return page->index;
1144 }
1145 
1146 bool page_mapped(struct page *page);
1147 struct address_space *page_mapping(struct page *page);
1148 
1149 /*
1150  * Return true only if the page has been allocated with
1151  * ALLOC_NO_WATERMARKS and the low watermark was not
1152  * met implying that the system is under some pressure.
1153  */
1154 static inline bool page_is_pfmemalloc(struct page *page)
1155 {
1156         /*
1157          * Page index cannot be this large so this must be
1158          * a pfmemalloc page.
1159          */
1160         return page->index == -1UL;
1161 }
1162 
1163 /*
1164  * Only to be called by the page allocator on a freshly allocated
1165  * page.
1166  */
1167 static inline void set_page_pfmemalloc(struct page *page)
1168 {
1169         page->index = -1UL;
1170 }
1171 
1172 static inline void clear_page_pfmemalloc(struct page *page)
1173 {
1174         page->index = 0;
1175 }
1176 
1177 /*
1178  * Different kinds of faults, as returned by handle_mm_fault().
1179  * Used to decide whether a process gets delivered SIGBUS or
1180  * just gets major/minor fault counters bumped up.
1181  */
1182 
1183 #define VM_FAULT_OOM    0x0001
1184 #define VM_FAULT_SIGBUS 0x0002
1185 #define VM_FAULT_MAJOR  0x0004
1186 #define VM_FAULT_WRITE  0x0008  /* Special case for get_user_pages */
1187 #define VM_FAULT_HWPOISON 0x0010        /* Hit poisoned small page */
1188 #define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
1189 #define VM_FAULT_SIGSEGV 0x0040
1190 
1191 #define VM_FAULT_NOPAGE 0x0100  /* ->fault installed the pte, not return page */
1192 #define VM_FAULT_LOCKED 0x0200  /* ->fault locked the returned page */
1193 #define VM_FAULT_RETRY  0x0400  /* ->fault blocked, must retry */
1194 #define VM_FAULT_FALLBACK 0x0800        /* huge page fault failed, fall back to small */
1195 #define VM_FAULT_DONE_COW   0x1000      /* ->fault has fully handled COW */
1196 #define VM_FAULT_NEEDDSYNC  0x2000      /* ->fault did not modify page tables
1197                                          * and needs fsync() to complete (for
1198                                          * synchronous page faults in DAX) */
1199 
1200 #define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \
1201                          VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \
1202                          VM_FAULT_FALLBACK)
1203 
1204 #define VM_FAULT_RESULT_TRACE \
1205         { VM_FAULT_OOM,                 "OOM" }, \
1206         { VM_FAULT_SIGBUS,              "SIGBUS" }, \
1207         { VM_FAULT_MAJOR,               "MAJOR" }, \
1208         { VM_FAULT_WRITE,               "WRITE" }, \
1209         { VM_FAULT_HWPOISON,            "HWPOISON" }, \
1210         { VM_FAULT_HWPOISON_LARGE,      "HWPOISON_LARGE" }, \
1211         { VM_FAULT_SIGSEGV,             "SIGSEGV" }, \
1212         { VM_FAULT_NOPAGE,              "NOPAGE" }, \
1213         { VM_FAULT_LOCKED,              "LOCKED" }, \
1214         { VM_FAULT_RETRY,               "RETRY" }, \
1215         { VM_FAULT_FALLBACK,            "FALLBACK" }, \
1216         { VM_FAULT_DONE_COW,            "DONE_COW" }, \
1217         { VM_FAULT_NEEDDSYNC,           "NEEDDSYNC" }
1218 
1219 /* Encode hstate index for a hwpoisoned large page */
1220 #define VM_FAULT_SET_HINDEX(x) ((x) << 12)
1221 #define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
1222 
1223 /*
1224  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
1225  */
1226 extern void pagefault_out_of_memory(void);
1227 
1228 #define offset_in_page(p)       ((unsigned long)(p) & ~PAGE_MASK)
1229 
1230 /*
1231  * Flags passed to show_mem() and show_free_areas() to suppress output in
1232  * various contexts.
1233  */
1234 #define SHOW_MEM_FILTER_NODES           (0x0001u)       /* disallowed nodes */
1235 
1236 extern void show_free_areas(unsigned int flags, nodemask_t *nodemask);
1237 
1238 extern bool can_do_mlock(void);
1239 extern int user_shm_lock(size_t, struct user_struct *);
1240 extern void user_shm_unlock(size_t, struct user_struct *);
1241 
1242 /*
1243  * Parameter block passed down to zap_pte_range in exceptional cases.
1244  */
1245 struct zap_details {
1246         struct address_space *check_mapping;    /* Check page->mapping if set */
1247         pgoff_t first_index;                    /* Lowest page->index to unmap */
1248         pgoff_t last_index;                     /* Highest page->index to unmap */
1249 };
1250 
1251 struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
1252                              pte_t pte, bool with_public_device);
1253 #define vm_normal_page(vma, addr, pte) _vm_normal_page(vma, addr, pte, false)
1254 
1255 struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
1256                                 pmd_t pmd);
1257 
1258 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1259                 unsigned long size);
1260 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
1261                 unsigned long size);
1262 void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
1263                 unsigned long start, unsigned long end);
1264 
1265 /**
1266  * mm_walk - callbacks for walk_page_range
1267  * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
1268  *             this handler should only handle pud_trans_huge() puds.
1269  *             the pmd_entry or pte_entry callbacks will be used for
1270  *             regular PUDs.
1271  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
1272  *             this handler is required to be able to handle
1273  *             pmd_trans_huge() pmds.  They may simply choose to
1274  *             split_huge_page() instead of handling it explicitly.
1275  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
1276  * @pte_hole: if set, called for each hole at all levels
1277  * @hugetlb_entry: if set, called for each hugetlb entry
1278  * @test_walk: caller specific callback function to determine whether
1279  *             we walk over the current vma or not. Returning 0
1280  *             value means "do page table walk over the current vma,"
1281  *             and a negative one means "abort current page table walk
1282  *             right now." 1 means "skip the current vma."
1283  * @mm:        mm_struct representing the target process of page table walk
1284  * @vma:       vma currently walked (NULL if walking outside vmas)
1285  * @private:   private data for callbacks' usage
1286  *
1287  * (see the comment on walk_page_range() for more details)
1288  */
1289 struct mm_walk {
1290         int (*pud_entry)(pud_t *pud, unsigned long addr,
1291                          unsigned long next, struct mm_walk *walk);
1292         int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
1293                          unsigned long next, struct mm_walk *walk);
1294         int (*pte_entry)(pte_t *pte, unsigned long addr,
1295                          unsigned long next, struct mm_walk *walk);
1296         int (*pte_hole)(unsigned long addr, unsigned long next,
1297                         struct mm_walk *walk);
1298         int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
1299                              unsigned long addr, unsigned long next,
1300                              struct mm_walk *walk);
1301         int (*test_walk)(unsigned long addr, unsigned long next,
1302                         struct mm_walk *walk);
1303         struct mm_struct *mm;
1304         struct vm_area_struct *vma;
1305         void *private;
1306 };
1307 
1308 int walk_page_range(unsigned long addr, unsigned long end,
1309                 struct mm_walk *walk);
1310 int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
1311 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
1312                 unsigned long end, unsigned long floor, unsigned long ceiling);
1313 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
1314                         struct vm_area_struct *vma);
1315 void unmap_mapping_range(struct address_space *mapping,
1316                 loff_t const holebegin, loff_t const holelen, int even_cows);
1317 int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
1318                              unsigned long *start, unsigned long *end,
1319                              pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
1320 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
1321         unsigned long *pfn);
1322 int follow_phys(struct vm_area_struct *vma, unsigned long address,
1323                 unsigned int flags, unsigned long *prot, resource_size_t *phys);
1324 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
1325                         void *buf, int len, int write);
1326 
1327 static inline void unmap_shared_mapping_range(struct address_space *mapping,
1328                 loff_t const holebegin, loff_t const holelen)
1329 {
1330         unmap_mapping_range(mapping, holebegin, holelen, 0);
1331 }
1332 
1333 extern void truncate_pagecache(struct inode *inode, loff_t new);
1334 extern void truncate_setsize(struct inode *inode, loff_t newsize);
1335 void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to);
1336 void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end);
1337 int truncate_inode_page(struct address_space *mapping, struct page *page);
1338 int generic_error_remove_page(struct address_space *mapping, struct page *page);
1339 int invalidate_inode_page(struct page *page);
1340 
1341 #ifdef CONFIG_MMU
1342 extern int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
1343                 unsigned int flags);
1344 extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1345                             unsigned long address, unsigned int fault_flags,
1346                             bool *unlocked);
1347 #else
1348 static inline int handle_mm_fault(struct vm_area_struct *vma,
1349                 unsigned long address, unsigned int flags)
1350 {
1351         /* should never happen if there's no MMU */
1352         BUG();
1353         return VM_FAULT_SIGBUS;
1354 }
1355 static inline int fixup_user_fault(struct task_struct *tsk,
1356                 struct mm_struct *mm, unsigned long address,
1357                 unsigned int fault_flags, bool *unlocked)
1358 {
1359         /* should never happen if there's no MMU */
1360         BUG();
1361         return -EFAULT;
1362 }
1363 #endif
1364 
1365 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
1366                 unsigned int gup_flags);
1367 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1368                 void *buf, int len, unsigned int gup_flags);
1369 extern int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1370                 unsigned long addr, void *buf, int len, unsigned int gup_flags);
1371 
1372 long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
1373                             unsigned long start, unsigned long nr_pages,
1374                             unsigned int gup_flags, struct page **pages,
1375                             struct vm_area_struct **vmas, int *locked);
1376 long get_user_pages(unsigned long start, unsigned long nr_pages,
1377                             unsigned int gup_flags, struct page **pages,
1378                             struct vm_area_struct **vmas);
1379 long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
1380                     unsigned int gup_flags, struct page **pages, int *locked);
1381 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
1382                     struct page **pages, unsigned int gup_flags);
1383 #ifdef CONFIG_FS_DAX
1384 long get_user_pages_longterm(unsigned long start, unsigned long nr_pages,
1385                             unsigned int gup_flags, struct page **pages,
1386                             struct vm_area_struct **vmas);
1387 #else
1388 static inline long get_user_pages_longterm(unsigned long start,
1389                 unsigned long nr_pages, unsigned int gup_flags,
1390                 struct page **pages, struct vm_area_struct **vmas)
1391 {
1392         return get_user_pages(start, nr_pages, gup_flags, pages, vmas);
1393 }
1394 #endif /* CONFIG_FS_DAX */
1395 
1396 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
1397                         struct page **pages);
1398 
1399 /* Container for pinned pfns / pages */
1400 struct frame_vector {
1401         unsigned int nr_allocated;      /* Number of frames we have space for */
1402         unsigned int nr_frames; /* Number of frames stored in ptrs array */
1403         bool got_ref;           /* Did we pin pages by getting page ref? */
1404         bool is_pfns;           /* Does array contain pages or pfns? */
1405         void *ptrs[0];          /* Array of pinned pfns / pages. Use
1406                                  * pfns_vector_pages() or pfns_vector_pfns()
1407                                  * for access */
1408 };
1409 
1410 struct frame_vector *frame_vector_create(unsigned int nr_frames);
1411 void frame_vector_destroy(struct frame_vector *vec);
1412 int get_vaddr_frames(unsigned long start, unsigned int nr_pfns,
1413                      unsigned int gup_flags, struct frame_vector *vec);
1414 void put_vaddr_frames(struct frame_vector *vec);
1415 int frame_vector_to_pages(struct frame_vector *vec);
1416 void frame_vector_to_pfns(struct frame_vector *vec);
1417 
1418 static inline unsigned int frame_vector_count(struct frame_vector *vec)
1419 {
1420         return vec->nr_frames;
1421 }
1422 
1423 static inline struct page **frame_vector_pages(struct frame_vector *vec)
1424 {
1425         if (vec->is_pfns) {
1426                 int err = frame_vector_to_pages(vec);
1427 
1428                 if (err)
1429                         return ERR_PTR(err);
1430         }
1431         return (struct page **)(vec->ptrs);
1432 }
1433 
1434 static inline unsigned long *frame_vector_pfns(struct frame_vector *vec)
1435 {
1436         if (!vec->is_pfns)
1437                 frame_vector_to_pfns(vec);
1438         return (unsigned long *)(vec->ptrs);
1439 }
1440 
1441 struct kvec;
1442 int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
1443                         struct page **pages);
1444 int get_kernel_page(unsigned long start, int write, struct page **pages);
1445 struct page *get_dump_page(unsigned long addr);
1446 
1447 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
1448 extern void do_invalidatepage(struct page *page, unsigned int offset,
1449                               unsigned int length);
1450 
1451 int __set_page_dirty_nobuffers(struct page *page);
1452 int __set_page_dirty_no_writeback(struct page *page);
1453 int redirty_page_for_writepage(struct writeback_control *wbc,
1454                                 struct page *page);
1455 void account_page_dirtied(struct page *page, struct address_space *mapping);
1456 void account_page_cleaned(struct page *page, struct address_space *mapping,
1457                           struct bdi_writeback *wb);
1458 int set_page_dirty(struct page *page);
1459 int set_page_dirty_lock(struct page *page);
1460 void __cancel_dirty_page(struct page *page);
1461 static inline void cancel_dirty_page(struct page *page)
1462 {
1463         /* Avoid atomic ops, locking, etc. when not actually needed. */
1464         if (PageDirty(page))
1465                 __cancel_dirty_page(page);
1466 }
1467 int clear_page_dirty_for_io(struct page *page);
1468 
1469 int get_cmdline(struct task_struct *task, char *buffer, int buflen);
1470 
1471 static inline bool vma_is_anonymous(struct vm_area_struct *vma)
1472 {
1473         return !vma->vm_ops;
1474 }
1475 
1476 #ifdef CONFIG_SHMEM
1477 /*
1478  * The vma_is_shmem is not inline because it is used only by slow
1479  * paths in userfault.
1480  */
1481 bool vma_is_shmem(struct vm_area_struct *vma);
1482 #else
1483 static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; }
1484 #endif
1485 
1486 int vma_is_stack_for_current(struct vm_area_struct *vma);
1487 
1488 extern unsigned long move_page_tables(struct vm_area_struct *vma,
1489                 unsigned long old_addr, struct vm_area_struct *new_vma,
1490                 unsigned long new_addr, unsigned long len,
1491                 bool need_rmap_locks);
1492 extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
1493                               unsigned long end, pgprot_t newprot,
1494                               int dirty_accountable, int prot_numa);
1495 extern int mprotect_fixup(struct vm_area_struct *vma,
1496                           struct vm_area_struct **pprev, unsigned long start,
1497                           unsigned long end, unsigned long newflags);
1498 
1499 /*
1500  * doesn't attempt to fault and will return short.
1501  */
1502 int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
1503                           struct page **pages);
1504 /*
1505  * per-process(per-mm_struct) statistics.
1506  */
1507 static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
1508 {
1509         long val = atomic_long_read(&mm->rss_stat.count[member]);
1510 
1511 #ifdef SPLIT_RSS_COUNTING
1512         /*
1513          * counter is updated in asynchronous manner and may go to minus.
1514          * But it's never be expected number for users.
1515          */
1516         if (val < 0)
1517                 val = 0;
1518 #endif
1519         return (unsigned long)val;
1520 }
1521 
1522 static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
1523 {
1524         atomic_long_add(value, &mm->rss_stat.count[member]);
1525 }
1526 
1527 static inline void inc_mm_counter(struct mm_struct *mm, int member)
1528 {
1529         atomic_long_inc(&mm->rss_stat.count[member]);
1530 }
1531 
1532 static inline void dec_mm_counter(struct mm_struct *mm, int member)
1533 {
1534         atomic_long_dec(&mm->rss_stat.count[member]);
1535 }
1536 
1537 /* Optimized variant when page is already known not to be PageAnon */
1538 static inline int mm_counter_file(struct page *page)
1539 {
1540         if (PageSwapBacked(page))
1541                 return MM_SHMEMPAGES;
1542         return MM_FILEPAGES;
1543 }
1544 
1545 static inline int mm_counter(struct page *page)
1546 {
1547         if (PageAnon(page))
1548                 return MM_ANONPAGES;
1549         return mm_counter_file(page);
1550 }
1551 
1552 static inline unsigned long get_mm_rss(struct mm_struct *mm)
1553 {
1554         return get_mm_counter(mm, MM_FILEPAGES) +
1555                 get_mm_counter(mm, MM_ANONPAGES) +
1556                 get_mm_counter(mm, MM_SHMEMPAGES);
1557 }
1558 
1559 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
1560 {
1561         return max(mm->hiwater_rss, get_mm_rss(mm));
1562 }
1563 
1564 static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
1565 {
1566         return max(mm->hiwater_vm, mm->total_vm);
1567 }
1568 
1569 static inline void update_hiwater_rss(struct mm_struct *mm)
1570 {
1571         unsigned long _rss = get_mm_rss(mm);
1572 
1573         if ((mm)->hiwater_rss < _rss)
1574                 (mm)->hiwater_rss = _rss;
1575 }
1576 
1577 static inline void update_hiwater_vm(struct mm_struct *mm)
1578 {
1579         if (mm->hiwater_vm < mm->total_vm)
1580                 mm->hiwater_vm = mm->total_vm;
1581 }
1582 
1583 static inline void reset_mm_hiwater_rss(struct mm_struct *mm)
1584 {
1585         mm->hiwater_rss = get_mm_rss(mm);
1586 }
1587 
1588 static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
1589                                          struct mm_struct *mm)
1590 {
1591         unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
1592 
1593         if (*maxrss < hiwater_rss)
1594                 *maxrss = hiwater_rss;
1595 }
1596 
1597 #if defined(SPLIT_RSS_COUNTING)
1598 void sync_mm_rss(struct mm_struct *mm);
1599 #else
1600 static inline void sync_mm_rss(struct mm_struct *mm)
1601 {
1602 }
1603 #endif
1604 
1605 #ifndef __HAVE_ARCH_PTE_DEVMAP
1606 static inline int pte_devmap(pte_t pte)
1607 {
1608         return 0;
1609 }
1610 #endif
1611 
1612 int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot);
1613 
1614 extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1615                                spinlock_t **ptl);
1616 static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1617                                     spinlock_t **ptl)
1618 {
1619         pte_t *ptep;
1620         __cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
1621         return ptep;
1622 }
1623 
1624 #ifdef __PAGETABLE_P4D_FOLDED
1625 static inline int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd,
1626                                                 unsigned long address)
1627 {
1628         return 0;
1629 }
1630 #else
1631 int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
1632 #endif
1633 
1634 #if defined(__PAGETABLE_PUD_FOLDED) || !defined(CONFIG_MMU)
1635 static inline int __pud_alloc(struct mm_struct *mm, p4d_t *p4d,
1636                                                 unsigned long address)
1637 {
1638         return 0;
1639 }
1640 static inline void mm_inc_nr_puds(struct mm_struct *mm) {}
1641 static inline void mm_dec_nr_puds(struct mm_struct *mm) {}
1642 
1643 #else
1644 int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address);
1645 
1646 static inline void mm_inc_nr_puds(struct mm_struct *mm)
1647 {
1648         atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);
1649 }
1650 
1651 static inline void mm_dec_nr_puds(struct mm_struct *mm)
1652 {
1653         atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);
1654 }
1655 #endif
1656 
1657 #if defined(__PAGETABLE_PMD_FOLDED) || !defined(CONFIG_MMU)
1658 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
1659                                                 unsigned long address)
1660 {
1661         return 0;
1662 }
1663 
1664 static inline void mm_inc_nr_pmds(struct mm_struct *mm) {}
1665 static inline void mm_dec_nr_pmds(struct mm_struct *mm) {}
1666 
1667 #else
1668 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
1669 
1670 static inline void mm_inc_nr_pmds(struct mm_struct *mm)
1671 {
1672         atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);
1673 }
1674 
1675 static inline void mm_dec_nr_pmds(struct mm_struct *mm)
1676 {
1677         atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);
1678 }
1679 #endif
1680 
1681 #ifdef CONFIG_MMU
1682 static inline void mm_pgtables_bytes_init(struct mm_struct *mm)
1683 {
1684         atomic_long_set(&mm->pgtables_bytes, 0);
1685 }
1686 
1687 static inline unsigned long mm_pgtables_bytes(const struct mm_struct *mm)
1688 {
1689         return atomic_long_read(&mm->pgtables_bytes);
1690 }
1691 
1692 static inline void mm_inc_nr_ptes(struct mm_struct *mm)
1693 {
1694         atomic_long_add(PTRS_PER_PTE * sizeof(pte_t), &mm->pgtables_bytes);
1695 }
1696 
1697 static inline void mm_dec_nr_ptes(struct mm_struct *mm)
1698 {
1699         atomic_long_sub(PTRS_PER_PTE * sizeof(pte_t), &mm->pgtables_bytes);
1700 }
1701 #else
1702 
1703 static inline void mm_pgtables_bytes_init(struct mm_struct *mm) {}
1704 static inline unsigned long mm_pgtables_bytes(const struct mm_struct *mm)
1705 {
1706         return 0;
1707 }
1708 
1709 static inline void mm_inc_nr_ptes(struct mm_struct *mm) {}
1710 static inline void mm_dec_nr_ptes(struct mm_struct *mm) {}
1711 #endif
1712 
1713 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);
1714 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
1715 
1716 /*
1717  * The following ifdef needed to get the 4level-fixup.h header to work.
1718  * Remove it when 4level-fixup.h has been removed.
1719  */
1720 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
1721 
1722 #ifndef __ARCH_HAS_5LEVEL_HACK
1723 static inline p4d_t *p4d_alloc(struct mm_struct *mm, pgd_t *pgd,
1724                 unsigned long address)
1725 {
1726         return (unlikely(pgd_none(*pgd)) && __p4d_alloc(mm, pgd, address)) ?
1727                 NULL : p4d_offset(pgd, address);
1728 }
1729 
1730 static inline pud_t *pud_alloc(struct mm_struct *mm, p4d_t *p4d,
1731                 unsigned long address)
1732 {
1733         return (unlikely(p4d_none(*p4d)) && __pud_alloc(mm, p4d, address)) ?
1734                 NULL : pud_offset(p4d, address);
1735 }
1736 #endif /* !__ARCH_HAS_5LEVEL_HACK */
1737 
1738 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
1739 {
1740         return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
1741                 NULL: pmd_offset(pud, address);
1742 }
1743 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
1744 
1745 #if USE_SPLIT_PTE_PTLOCKS
1746 #if ALLOC_SPLIT_PTLOCKS
1747 void __init ptlock_cache_init(void);
1748 extern bool ptlock_alloc(struct page *page);
1749 extern void ptlock_free(struct page *page);
1750 
1751 static inline spinlock_t *ptlock_ptr(struct page *page)
1752 {
1753         return page->ptl;
1754 }
1755 #else /* ALLOC_SPLIT_PTLOCKS */
1756 static inline void ptlock_cache_init(void)
1757 {
1758 }
1759 
1760 static inline bool ptlock_alloc(struct page *page)
1761 {
1762         return true;
1763 }
1764 
1765 static inline void ptlock_free(struct page *page)
1766 {
1767 }
1768 
1769 static inline spinlock_t *ptlock_ptr(struct page *page)
1770 {
1771         return &page->ptl;
1772 }
1773 #endif /* ALLOC_SPLIT_PTLOCKS */
1774 
1775 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1776 {
1777         return ptlock_ptr(pmd_page(*pmd));
1778 }
1779 
1780 static inline bool ptlock_init(struct page *page)
1781 {
1782         /*
1783          * prep_new_page() initialize page->private (and therefore page->ptl)
1784          * with 0. Make sure nobody took it in use in between.
1785          *
1786          * It can happen if arch try to use slab for page table allocation:
1787          * slab code uses page->slab_cache, which share storage with page->ptl.
1788          */
1789         VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
1790         if (!ptlock_alloc(page))
1791                 return false;
1792         spin_lock_init(ptlock_ptr(page));
1793         return true;
1794 }
1795 
1796 /* Reset page->mapping so free_pages_check won't complain. */
1797 static inline void pte_lock_deinit(struct page *page)
1798 {
1799         page->mapping = NULL;
1800         ptlock_free(page);
1801 }
1802 
1803 #else   /* !USE_SPLIT_PTE_PTLOCKS */
1804 /*
1805  * We use mm->page_table_lock to guard all pagetable pages of the mm.
1806  */
1807 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
1808 {
1809         return &mm->page_table_lock;
1810 }
1811 static inline void ptlock_cache_init(void) {}
1812 static inline bool ptlock_init(struct page *page) { return true; }
1813 static inline void pte_lock_deinit(struct page *page) {}
1814 #endif /* USE_SPLIT_PTE_PTLOCKS */
1815 
1816 static inline void pgtable_init(void)
1817 {
1818         ptlock_cache_init();
1819         pgtable_cache_init();
1820 }
1821 
1822 static inline bool pgtable_page_ctor(struct page *page)
1823 {
1824         if (!ptlock_init(page))
1825                 return false;
1826         inc_zone_page_state(page, NR_PAGETABLE);
1827         return true;
1828 }
1829 
1830 static inline void pgtable_page_dtor(struct page *page)
1831 {
1832         pte_lock_deinit(page);
1833         dec_zone_page_state(page, NR_PAGETABLE);
1834 }
1835 
1836 #define pte_offset_map_lock(mm, pmd, address, ptlp)     \
1837 ({                                                      \
1838         spinlock_t *__ptl = pte_lockptr(mm, pmd);       \
1839         pte_t *__pte = pte_offset_map(pmd, address);    \
1840         *(ptlp) = __ptl;                                \
1841         spin_lock(__ptl);                               \
1842         __pte;                                          \
1843 })
1844 
1845 #define pte_unmap_unlock(pte, ptl)      do {            \
1846         spin_unlock(ptl);                               \
1847         pte_unmap(pte);                                 \
1848 } while (0)
1849 
1850 #define pte_alloc(mm, pmd, address)                     \
1851         (unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, pmd, address))
1852 
1853 #define pte_alloc_map(mm, pmd, address)                 \
1854         (pte_alloc(mm, pmd, address) ? NULL : pte_offset_map(pmd, address))
1855 
1856 #define pte_alloc_map_lock(mm, pmd, address, ptlp)      \
1857         (pte_alloc(mm, pmd, address) ?                  \
1858                  NULL : pte_offset_map_lock(mm, pmd, address, ptlp))
1859 
1860 #define pte_alloc_kernel(pmd, address)                  \
1861         ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
1862                 NULL: pte_offset_kernel(pmd, address))
1863 
1864 #if USE_SPLIT_PMD_PTLOCKS
1865 
1866 static struct page *pmd_to_page(pmd_t *pmd)
1867 {
1868         unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
1869         return virt_to_page((void *)((unsigned long) pmd & mask));
1870 }
1871 
1872 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1873 {
1874         return ptlock_ptr(pmd_to_page(pmd));
1875 }
1876 
1877 static inline bool pgtable_pmd_page_ctor(struct page *page)
1878 {
1879 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1880         page->pmd_huge_pte = NULL;
1881 #endif
1882         return ptlock_init(page);
1883 }
1884 
1885 static inline void pgtable_pmd_page_dtor(struct page *page)
1886 {
1887 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1888         VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
1889 #endif
1890         ptlock_free(page);
1891 }
1892 
1893 #define pmd_huge_pte(mm, pmd) (pmd_to_page(pmd)->pmd_huge_pte)
1894 
1895 #else
1896 
1897 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
1898 {
1899         return &mm->page_table_lock;
1900 }
1901 
1902 static inline bool pgtable_pmd_page_ctor(struct page *page) { return true; }
1903 static inline void pgtable_pmd_page_dtor(struct page *page) {}
1904 
1905 #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
1906 
1907 #endif
1908 
1909 static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
1910 {
1911         spinlock_t *ptl = pmd_lockptr(mm, pmd);
1912         spin_lock(ptl);
1913         return ptl;
1914 }
1915 
1916 /*
1917  * No scalability reason to split PUD locks yet, but follow the same pattern
1918  * as the PMD locks to make it easier if we decide to.  The VM should not be
1919  * considered ready to switch to split PUD locks yet; there may be places
1920  * which need to be converted from page_table_lock.
1921  */
1922 static inline spinlock_t *pud_lockptr(struct mm_struct *mm, pud_t *pud)
1923 {
1924         return &mm->page_table_lock;
1925 }
1926 
1927 static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud)
1928 {
1929         spinlock_t *ptl = pud_lockptr(mm, pud);
1930 
1931         spin_lock(ptl);
1932         return ptl;
1933 }
1934 
1935 extern void __init pagecache_init(void);
1936 extern void free_area_init(unsigned long * zones_size);
1937 extern void free_area_init_node(int nid, unsigned long * zones_size,
1938                 unsigned long zone_start_pfn, unsigned long *zholes_size);
1939 extern void free_initmem(void);
1940 
1941 /*
1942  * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
1943  * into the buddy system. The freed pages will be poisoned with pattern
1944  * "poison" if it's within range [0, UCHAR_MAX].
1945  * Return pages freed into the buddy system.
1946  */
1947 extern unsigned long free_reserved_area(void *start, void *end,
1948                                         int poison, char *s);
1949 
1950 #ifdef  CONFIG_HIGHMEM
1951 /*
1952  * Free a highmem page into the buddy system, adjusting totalhigh_pages
1953  * and totalram_pages.
1954  */
1955 extern void free_highmem_page(struct page *page);
1956 #endif
1957 
1958 extern void adjust_managed_page_count(struct page *page, long count);
1959 extern void mem_init_print_info(const char *str);
1960 
1961 extern void reserve_bootmem_region(phys_addr_t start, phys_addr_t end);
1962 
1963 /* Free the reserved page into the buddy system, so it gets managed. */
1964 static inline void __free_reserved_page(struct page *page)
1965 {
1966         ClearPageReserved(page);
1967         init_page_count(page);
1968         __free_page(page);
1969 }
1970 
1971 static inline void free_reserved_page(struct page *page)
1972 {
1973         __free_reserved_page(page);
1974         adjust_managed_page_count(page, 1);
1975 }
1976 
1977 static inline void mark_page_reserved(struct page *page)
1978 {
1979         SetPageReserved(page);
1980         adjust_managed_page_count(page, -1);
1981 }
1982 
1983 /*
1984  * Default method to free all the __init memory into the buddy system.
1985  * The freed pages will be poisoned with pattern "poison" if it's within
1986  * range [0, UCHAR_MAX].
1987  * Return pages freed into the buddy system.
1988  */
1989 static inline unsigned long free_initmem_default(int poison)
1990 {
1991         extern char __init_begin[], __init_end[];
1992 
1993         return free_reserved_area(&__init_begin, &__init_end,
1994                                   poison, "unused kernel");
1995 }
1996 
1997 static inline unsigned long get_num_physpages(void)
1998 {
1999         int nid;
2000         unsigned long phys_pages = 0;
2001 
2002         for_each_online_node(nid)
2003                 phys_pages += node_present_pages(nid);
2004 
2005         return phys_pages;
2006 }
2007 
2008 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
2009 /*
2010  * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
2011  * zones, allocate the backing mem_map and account for memory holes in a more
2012  * architecture independent manner. This is a substitute for creating the
2013  * zone_sizes[] and zholes_size[] arrays and passing them to
2014  * free_area_init_node()
2015  *
2016  * An architecture is expected to register range of page frames backed by
2017  * physical memory with memblock_add[_node]() before calling
2018  * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
2019  * usage, an architecture is expected to do something like
2020  *
2021  * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
2022  *                                                       max_highmem_pfn};
2023  * for_each_valid_physical_page_range()
2024  *      memblock_add_node(base, size, nid)
2025  * free_area_init_nodes(max_zone_pfns);
2026  *
2027  * free_bootmem_with_active_regions() calls free_bootmem_node() for each
2028  * registered physical page range.  Similarly
2029  * sparse_memory_present_with_active_regions() calls memory_present() for
2030  * each range when SPARSEMEM is enabled.
2031  *
2032  * See mm/page_alloc.c for more information on each function exposed by
2033  * CONFIG_HAVE_MEMBLOCK_NODE_MAP.
2034  */
2035 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
2036 unsigned long node_map_pfn_alignment(void);
2037 unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
2038                                                 unsigned long end_pfn);
2039 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
2040                                                 unsigned long end_pfn);
2041 extern void get_pfn_range_for_nid(unsigned int nid,
2042                         unsigned long *start_pfn, unsigned long *end_pfn);
2043 extern unsigned long find_min_pfn_with_active_regions(void);
2044 extern void free_bootmem_with_active_regions(int nid,
2045                                                 unsigned long max_low_pfn);
2046 extern void sparse_memory_present_with_active_regions(int nid);
2047 
2048 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
2049 
2050 #if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
2051     !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
2052 static inline int __early_pfn_to_nid(unsigned long pfn,
2053                                         struct mminit_pfnnid_cache *state)
2054 {
2055         return 0;
2056 }
2057 #else
2058 /* please see mm/page_alloc.c */
2059 extern int __meminit early_pfn_to_nid(unsigned long pfn);
2060 /* there is a per-arch backend function. */
2061 extern int __meminit __early_pfn_to_nid(unsigned long pfn,
2062                                         struct mminit_pfnnid_cache *state);
2063 #endif
2064 
2065 #ifdef CONFIG_HAVE_MEMBLOCK
2066 void zero_resv_unavail(void);
2067 #else
2068 static inline void zero_resv_unavail(void) {}
2069 #endif
2070 
2071 extern void set_dma_reserve(unsigned long new_dma_reserve);
2072 extern void memmap_init_zone(unsigned long, int, unsigned long,
2073                                 unsigned long, enum memmap_context);
2074 extern void setup_per_zone_wmarks(void);
2075 extern int __meminit init_per_zone_wmark_min(void);
2076 extern void mem_init(void);
2077 extern void __init mmap_init(void);
2078 extern void show_mem(unsigned int flags, nodemask_t *nodemask);
2079 extern long si_mem_available(void);
2080 extern void si_meminfo(struct sysinfo * val);
2081 extern void si_meminfo_node(struct sysinfo *val, int nid);
2082 #ifdef __HAVE_ARCH_RESERVED_KERNEL_PAGES
2083 extern unsigned long arch_reserved_kernel_pages(void);
2084 #endif
2085 
2086 extern __printf(3, 4)
2087 void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...);
2088 
2089 extern void setup_per_cpu_pageset(void);
2090 
2091 extern void zone_pcp_update(struct zone *zone);
2092 extern void zone_pcp_reset(struct zone *zone);
2093 
2094 /* page_alloc.c */
2095 extern int min_free_kbytes;
2096 extern int watermark_scale_factor;
2097 
2098 /* nommu.c */
2099 extern atomic_long_t mmap_pages_allocated;
2100 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
2101 
2102 /* interval_tree.c */
2103 void vma_interval_tree_insert(struct vm_area_struct *node,
2104                               struct rb_root_cached *root);
2105 void vma_interval_tree_insert_after(struct vm_area_struct *node,
2106                                     struct vm_area_struct *prev,
2107                                     struct rb_root_cached *root);
2108 void vma_interval_tree_remove(struct vm_area_struct *node,
2109                               struct rb_root_cached *root);
2110 struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root_cached *root,
2111                                 unsigned long start, unsigned long last);
2112 struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
2113                                 unsigned long start, unsigned long last);
2114 
2115 #define vma_interval_tree_foreach(vma, root, start, last)               \
2116         for (vma = vma_interval_tree_iter_first(root, start, last);     \
2117              vma; vma = vma_interval_tree_iter_next(vma, start, last))
2118 
2119 void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
2120                                    struct rb_root_cached *root);
2121 void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
2122                                    struct rb_root_cached *root);
2123 struct anon_vma_chain *
2124 anon_vma_interval_tree_iter_first(struct rb_root_cached *root,
2125                                   unsigned long start, unsigned long last);
2126 struct anon_vma_chain *anon_vma_interval_tree_iter_next(
2127         struct anon_vma_chain *node, unsigned long start, unsigned long last);
2128 #ifdef CONFIG_DEBUG_VM_RB
2129 void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
2130 #endif
2131 
2132 #define anon_vma_interval_tree_foreach(avc, root, start, last)           \
2133         for (avc = anon_vma_interval_tree_iter_first(root, start, last); \
2134              avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
2135 
2136 /* mmap.c */
2137 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
2138 extern int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
2139         unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert,
2140         struct vm_area_struct *expand);
2141 static inline int vma_adjust(struct vm_area_struct *vma, unsigned long start,
2142         unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
2143 {
2144         return __vma_adjust(vma, start, end, pgoff, insert, NULL);
2145 }
2146 extern struct vm_area_struct *vma_merge(struct mm_struct *,
2147         struct vm_area_struct *prev, unsigned long addr, unsigned long end,
2148         unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
2149         struct mempolicy *, struct vm_userfaultfd_ctx);
2150 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
2151 extern int __split_vma(struct mm_struct *, struct vm_area_struct *,
2152         unsigned long addr, int new_below);
2153 extern int split_vma(struct mm_struct *, struct vm_area_struct *,
2154         unsigned long addr, int new_below);
2155 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
2156 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
2157         struct rb_node **, struct rb_node *);
2158 extern void unlink_file_vma(struct vm_area_struct *);
2159 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
2160         unsigned long addr, unsigned long len, pgoff_t pgoff,
2161         bool *need_rmap_locks);
2162 extern void exit_mmap(struct mm_struct *);
2163 
2164 static inline int check_data_rlimit(unsigned long rlim,
2165                                     unsigned long new,
2166                                     unsigned long start,
2167                                     unsigned long end_data,
2168                                     unsigned long start_data)
2169 {
2170         if (rlim < RLIM_INFINITY) {
2171                 if (((new - start) + (end_data - start_data)) > rlim)
2172                         return -ENOSPC;
2173         }
2174 
2175         return 0;
2176 }
2177 
2178 extern int mm_take_all_locks(struct mm_struct *mm);
2179 extern void mm_drop_all_locks(struct mm_struct *mm);
2180 
2181 extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
2182 extern struct file *get_mm_exe_file(struct mm_struct *mm);
2183 extern struct file *get_task_exe_file(struct task_struct *task);
2184 
2185 extern bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long npages);
2186 extern void vm_stat_account(struct mm_struct *, vm_flags_t, long npages);
2187 
2188 extern bool vma_is_special_mapping(const struct vm_area_struct *vma,
2189                                    const struct vm_special_mapping *sm);
2190 extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
2191                                    unsigned long addr, unsigned long len,
2192                                    unsigned long flags,
2193                                    const struct vm_special_mapping *spec);
2194 /* This is an obsolete alternative to _install_special_mapping. */
2195 extern int install_special_mapping(struct mm_struct *mm,
2196                                    unsigned long addr, unsigned long len,
2197                                    unsigned long flags, struct page **pages);
2198 
2199 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
2200 
2201 extern unsigned long mmap_region(struct file *file, unsigned long addr,
2202         unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
2203         struct list_head *uf);
2204 extern unsigned long do_mmap(struct file *file, unsigned long addr,
2205         unsigned long len, unsigned long prot, unsigned long flags,
2206         vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate,
2207         struct list_head *uf);
2208 extern int do_munmap(struct mm_struct *, unsigned long, size_t,
2209                      struct list_head *uf);
2210 
2211 static inline unsigned long
2212 do_mmap_pgoff(struct file *file, unsigned long addr,
2213         unsigned long len, unsigned long prot, unsigned long flags,
2214         unsigned long pgoff, unsigned long *populate,
2215         struct list_head *uf)
2216 {
2217         return do_mmap(file, addr, len, prot, flags, 0, pgoff, populate, uf);
2218 }
2219 
2220 #ifdef CONFIG_MMU
2221 extern int __mm_populate(unsigned long addr, unsigned long len,
2222                          int ignore_errors);
2223 static inline void mm_populate(unsigned long addr, unsigned long len)
2224 {
2225         /* Ignore errors */
2226         (void) __mm_populate(addr, len, 1);
2227 }
2228 #else
2229 static inline void mm_populate(unsigned long addr, unsigned long len) {}
2230 #endif
2231 
2232 /* These take the mm semaphore themselves */
2233 extern int __must_check vm_brk(unsigned long, unsigned long);
2234 extern int __must_check vm_brk_flags(unsigned long, unsigned long, unsigned long);
2235 extern int vm_munmap(unsigned long, size_t);
2236 extern unsigned long __must_check vm_mmap(struct file *, unsigned long,
2237         unsigned long, unsigned long,
2238         unsigned long, unsigned long);
2239 
2240 struct vm_unmapped_area_info {
2241 #define VM_UNMAPPED_AREA_TOPDOWN 1
2242         unsigned long flags;
2243         unsigned long length;
2244         unsigned long low_limit;
2245         unsigned long high_limit;
2246         unsigned long align_mask;
2247         unsigned long align_offset;
2248 };
2249 
2250 extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
2251 extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
2252 
2253 /*
2254  * Search for an unmapped address range.
2255  *
2256  * We are looking for a range that:
2257  * - does not intersect with any VMA;
2258  * - is contained within the [low_limit, high_limit) interval;
2259  * - is at least the desired size.
2260  * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
2261  */
2262 static inline unsigned long
2263 vm_unmapped_area(struct vm_unmapped_area_info *info)
2264 {
2265         if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
2266                 return unmapped_area_topdown(info);
2267         else
2268                 return unmapped_area(info);
2269 }
2270 
2271 /* truncate.c */
2272 extern void truncate_inode_pages(struct address_space *, loff_t);
2273 extern void truncate_inode_pages_range(struct address_space *,
2274                                        loff_t lstart, loff_t lend);
2275 extern void truncate_inode_pages_final(struct address_space *);
2276 
2277 /* generic vm_area_ops exported for stackable file systems */
2278 extern int filemap_fault(struct vm_fault *vmf);
2279 extern void filemap_map_pages(struct vm_fault *vmf,
2280                 pgoff_t start_pgoff, pgoff_t end_pgoff);
2281 extern int filemap_page_mkwrite(struct vm_fault *vmf);
2282 
2283 /* mm/page-writeback.c */
2284 int __must_check write_one_page(struct page *page);
2285 void task_dirty_inc(struct task_struct *tsk);
2286 
2287 /* readahead.c */
2288 #define VM_MAX_READAHEAD        128     /* kbytes */
2289 #define VM_MIN_READAHEAD        16      /* kbytes (includes current page) */
2290 
2291 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
2292                         pgoff_t offset, unsigned long nr_to_read);
2293 
2294 void page_cache_sync_readahead(struct address_space *mapping,
2295                                struct file_ra_state *ra,
2296                                struct file *filp,
2297                                pgoff_t offset,
2298                                unsigned long size);
2299 
2300 void page_cache_async_readahead(struct address_space *mapping,
2301                                 struct file_ra_state *ra,
2302                                 struct file *filp,
2303                                 struct page *pg,
2304                                 pgoff_t offset,
2305                                 unsigned long size);
2306 
2307 extern unsigned long stack_guard_gap;
2308 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
2309 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
2310 
2311 /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
2312 extern int expand_downwards(struct vm_area_struct *vma,
2313                 unsigned long address);
2314 #if VM_GROWSUP
2315 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
2316 #else
2317   #define expand_upwards(vma, address) (0)
2318 #endif
2319 
2320 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
2321 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
2322 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
2323                                              struct vm_area_struct **pprev);
2324 
2325 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
2326    NULL if none.  Assume start_addr < end_addr. */
2327 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
2328 {
2329         struct vm_area_struct * vma = find_vma(mm,start_addr);
2330 
2331         if (vma && end_addr <= vma->vm_start)
2332                 vma = NULL;
2333         return vma;
2334 }
2335 
2336 static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
2337 {
2338         unsigned long vm_start = vma->vm_start;
2339 
2340         if (vma->vm_flags & VM_GROWSDOWN) {
2341                 vm_start -= stack_guard_gap;
2342                 if (vm_start > vma->vm_start)
2343                         vm_start = 0;
2344         }
2345         return vm_start;
2346 }
2347 
2348 static inline unsigned long vm_end_gap(struct vm_area_struct *vma)
2349 {
2350         unsigned long vm_end = vma->vm_end;
2351 
2352         if (vma->vm_flags & VM_GROWSUP) {
2353                 vm_end += stack_guard_gap;
2354                 if (vm_end < vma->vm_end)
2355                         vm_end = -PAGE_SIZE;
2356         }
2357         return vm_end;
2358 }
2359 
2360 static inline unsigned long vma_pages(struct vm_area_struct *vma)
2361 {
2362         return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
2363 }
2364 
2365 /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
2366 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
2367                                 unsigned long vm_start, unsigned long vm_end)
2368 {
2369         struct vm_area_struct *vma = find_vma(mm, vm_start);
2370 
2371         if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
2372                 vma = NULL;
2373 
2374         return vma;
2375 }
2376 
2377 #ifdef CONFIG_MMU
2378 pgprot_t vm_get_page_prot(unsigned long vm_flags);
2379 void vma_set_page_prot(struct vm_area_struct *vma);
2380 #else
2381 static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
2382 {
2383         return __pgprot(0);
2384 }
2385 static inline void vma_set_page_prot(struct vm_area_struct *vma)
2386 {
2387         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
2388 }
2389 #endif
2390 
2391 #ifdef CONFIG_NUMA_BALANCING
2392 unsigned long change_prot_numa(struct vm_area_struct *vma,
2393                         unsigned long start, unsigned long end);
2394 #endif
2395 
2396 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
2397 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
2398                         unsigned long pfn, unsigned long size, pgprot_t);
2399 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
2400 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2401                         unsigned long pfn);
2402 int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
2403                         unsigned long pfn, pgprot_t pgprot);
2404 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2405                         pfn_t pfn);
2406 int vm_insert_mixed_mkwrite(struct vm_area_struct *vma, unsigned long addr,
2407                         pfn_t pfn);
2408 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
2409 
2410 
2411 struct page *follow_page_mask(struct vm_area_struct *vma,
2412                               unsigned long address, unsigned int foll_flags,
2413                               unsigned int *page_mask);
2414 
2415 static inline struct page *follow_page(struct vm_area_struct *vma,
2416                 unsigned long address, unsigned int foll_flags)
2417 {
2418         unsigned int unused_page_mask;
2419         return follow_page_mask(vma, address, foll_flags, &unused_page_mask);
2420 }
2421 
2422 #define FOLL_WRITE      0x01    /* check pte is writable */
2423 #define FOLL_TOUCH      0x02    /* mark page accessed */
2424 #define FOLL_GET        0x04    /* do get_page on page */
2425 #define FOLL_DUMP       0x08    /* give error on hole if it would be zero */
2426 #define FOLL_FORCE      0x10    /* get_user_pages read/write w/o permission */
2427 #define FOLL_NOWAIT     0x20    /* if a disk transfer is needed, start the IO
2428                                  * and return without waiting upon it */
2429 #define FOLL_POPULATE   0x40    /* fault in page */
2430 #define FOLL_SPLIT      0x80    /* don't return transhuge pages, split them */
2431 #define FOLL_HWPOISON   0x100   /* check page is hwpoisoned */
2432 #define FOLL_NUMA       0x200   /* force NUMA hinting page fault */
2433 #define FOLL_MIGRATION  0x400   /* wait for page to replace migration entry */
2434 #define FOLL_TRIED      0x800   /* a retry, previous pass started an IO */
2435 #define FOLL_MLOCK      0x1000  /* lock present pages */
2436 #define FOLL_REMOTE     0x2000  /* we are working on non-current tsk/mm */
2437 #define FOLL_COW        0x4000  /* internal GUP flag */
2438 
2439 static inline int vm_fault_to_errno(int vm_fault, int foll_flags)
2440 {
2441         if (vm_fault & VM_FAULT_OOM)
2442                 return -ENOMEM;
2443         if (vm_fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
2444                 return (foll_flags & FOLL_HWPOISON) ? -EHWPOISON : -EFAULT;
2445         if (vm_fault & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV))
2446                 return -EFAULT;
2447         return 0;
2448 }
2449 
2450 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
2451                         void *data);
2452 extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
2453                                unsigned long size, pte_fn_t fn, void *data);
2454 
2455 
2456 #ifdef CONFIG_PAGE_POISONING
2457 extern bool page_poisoning_enabled(void);
2458 extern void kernel_poison_pages(struct page *page, int numpages, int enable);
2459 extern bool page_is_poisoned(struct page *page);
2460 #else
2461 static inline bool page_poisoning_enabled(void) { return false; }
2462 static inline void kernel_poison_pages(struct page *page, int numpages,
2463                                         int enable) { }
2464 static inline bool page_is_poisoned(struct page *page) { return false; }
2465 #endif
2466 
2467 #ifdef CONFIG_DEBUG_PAGEALLOC
2468 extern bool _debug_pagealloc_enabled;
2469 extern void __kernel_map_pages(struct page *page, int numpages, int enable);
2470 
2471 static inline bool debug_pagealloc_enabled(void)
2472 {
2473         return _debug_pagealloc_enabled;
2474 }
2475 
2476 static inline void
2477 kernel_map_pages(struct page *page, int numpages, int enable)
2478 {
2479         if (!debug_pagealloc_enabled())
2480                 return;
2481 
2482         __kernel_map_pages(page, numpages, enable);
2483 }
2484 #ifdef CONFIG_HIBERNATION
2485 extern bool kernel_page_present(struct page *page);
2486 #endif  /* CONFIG_HIBERNATION */
2487 #else   /* CONFIG_DEBUG_PAGEALLOC */
2488 static inline void
2489 kernel_map_pages(struct page *page, int numpages, int enable) {}
2490 #ifdef CONFIG_HIBERNATION
2491 static inline bool kernel_page_present(struct page *page) { return true; }
2492 #endif  /* CONFIG_HIBERNATION */
2493 static inline bool debug_pagealloc_enabled(void)
2494 {
2495         return false;
2496 }
2497 #endif  /* CONFIG_DEBUG_PAGEALLOC */
2498 
2499 #ifdef __HAVE_ARCH_GATE_AREA
2500 extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
2501 extern int in_gate_area_no_mm(unsigned long addr);
2502 extern int in_gate_area(struct mm_struct *mm, unsigned long addr);
2503 #else
2504 static inline struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
2505 {
2506         return NULL;
2507 }
2508 static inline int in_gate_area_no_mm(unsigned long addr) { return 0; }
2509 static inline int in_gate_area(struct mm_struct *mm, unsigned long addr)
2510 {
2511         return 0;
2512 }
2513 #endif  /* __HAVE_ARCH_GATE_AREA */
2514 
2515 extern bool process_shares_mm(struct task_struct *p, struct mm_struct *mm);
2516 
2517 #ifdef CONFIG_SYSCTL
2518 extern int sysctl_drop_caches;
2519 int drop_caches_sysctl_handler(struct ctl_table *, int,
2520                                         void __user *, size_t *, loff_t *);
2521 #endif
2522 
2523 void drop_slab(void);
2524 void drop_slab_node(int nid);
2525 
2526 #ifndef CONFIG_MMU
2527 #define randomize_va_space 0
2528 #else
2529 extern int randomize_va_space;
2530 #endif
2531 
2532 const char * arch_vma_name(struct vm_area_struct *vma);
2533 void print_vma_addr(char *prefix, unsigned long rip);
2534 
2535 void sparse_mem_maps_populate_node(struct page **map_map,
2536                                    unsigned long pnum_begin,
2537                                    unsigned long pnum_end,
2538                                    unsigned long map_count,
2539                                    int nodeid);
2540 
2541 struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
2542 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
2543 p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
2544 pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
2545 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
2546 pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
2547 void *vmemmap_alloc_block(unsigned long size, int node);
2548 struct vmem_altmap;
2549 void *__vmemmap_alloc_block_buf(unsigned long size, int node,
2550                 struct vmem_altmap *altmap);
2551 static inline void *vmemmap_alloc_block_buf(unsigned long size, int node)
2552 {
2553         return __vmemmap_alloc_block_buf(size, node, NULL);
2554 }
2555 
2556 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
2557 int vmemmap_populate_basepages(unsigned long start, unsigned long end,
2558                                int node);
2559 int vmemmap_populate(unsigned long start, unsigned long end, int node);
2560 void vmemmap_populate_print_last(void);
2561 #ifdef CONFIG_MEMORY_HOTPLUG
2562 void vmemmap_free(unsigned long start, unsigned long end);
2563 #endif
2564 void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
2565                                   unsigned long nr_pages);
2566 
2567 enum mf_flags {
2568         MF_COUNT_INCREASED = 1 << 0,
2569         MF_ACTION_REQUIRED = 1 << 1,
2570         MF_MUST_KILL = 1 << 2,
2571         MF_SOFT_OFFLINE = 1 << 3,
2572 };
2573 extern int memory_failure(unsigned long pfn, int trapno, int flags);
2574 extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
2575 extern int unpoison_memory(unsigned long pfn);
2576 extern int get_hwpoison_page(struct page *page);
2577 #define put_hwpoison_page(page) put_page(page)
2578 extern int sysctl_memory_failure_early_kill;
2579 extern int sysctl_memory_failure_recovery;
2580 extern void shake_page(struct page *p, int access);
2581 extern atomic_long_t num_poisoned_pages;
2582 extern int soft_offline_page(struct page *page, int flags);
2583 
2584 
2585 /*
2586  * Error handlers for various types of pages.
2587  */
2588 enum mf_result {
2589         MF_IGNORED,     /* Error: cannot be handled */
2590         MF_FAILED,      /* Error: handling failed */
2591         MF_DELAYED,     /* Will be handled later */
2592         MF_RECOVERED,   /* Successfully recovered */
2593 };
2594 
2595 enum mf_action_page_type {
2596         MF_MSG_KERNEL,
2597         MF_MSG_KERNEL_HIGH_ORDER,
2598         MF_MSG_SLAB,
2599         MF_MSG_DIFFERENT_COMPOUND,
2600         MF_MSG_POISONED_HUGE,
2601         MF_MSG_HUGE,
2602         MF_MSG_FREE_HUGE,
2603         MF_MSG_UNMAP_FAILED,
2604         MF_MSG_DIRTY_SWAPCACHE,
2605         MF_MSG_CLEAN_SWAPCACHE,
2606         MF_MSG_DIRTY_MLOCKED_LRU,
2607         MF_MSG_CLEAN_MLOCKED_LRU,
2608         MF_MSG_DIRTY_UNEVICTABLE_LRU,
2609         MF_MSG_CLEAN_UNEVICTABLE_LRU,
2610         MF_MSG_DIRTY_LRU,
2611         MF_MSG_CLEAN_LRU,
2612         MF_MSG_TRUNCATED_LRU,
2613         MF_MSG_BUDDY,
2614         MF_MSG_BUDDY_2ND,
2615         MF_MSG_UNKNOWN,
2616 };
2617 
2618 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
2619 extern void clear_huge_page(struct page *page,
2620                             unsigned long addr_hint,
2621                             unsigned int pages_per_huge_page);
2622 extern void copy_user_huge_page(struct page *dst, struct page *src,
2623                                 unsigned long addr, struct vm_area_struct *vma,
2624                                 unsigned int pages_per_huge_page);
2625 extern long copy_huge_page_from_user(struct page *dst_page,
2626                                 const void __user *usr_src,
2627                                 unsigned int pages_per_huge_page,
2628                                 bool allow_pagefault);
2629 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
2630 
2631 extern struct page_ext_operations debug_guardpage_ops;
2632 
2633 #ifdef CONFIG_DEBUG_PAGEALLOC
2634 extern unsigned int _debug_guardpage_minorder;
2635 extern bool _debug_guardpage_enabled;
2636 
2637 static inline unsigned int debug_guardpage_minorder(void)
2638 {
2639         return _debug_guardpage_minorder;
2640 }
2641 
2642 static inline bool debug_guardpage_enabled(void)
2643 {
2644         return _debug_guardpage_enabled;
2645 }
2646 
2647 static inline bool page_is_guard(struct page *page)
2648 {
2649         struct page_ext *page_ext;
2650 
2651         if (!debug_guardpage_enabled())
2652                 return false;
2653 
2654         page_ext = lookup_page_ext(page);
2655         if (unlikely(!page_ext))
2656                 return false;
2657 
2658         return test_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
2659 }
2660 #else
2661 static inline unsigned int debug_guardpage_minorder(void) { return 0; }
2662 static inline bool debug_guardpage_enabled(void) { return false; }
2663 static inline bool page_is_guard(struct page *page) { return false; }
2664 #endif /* CONFIG_DEBUG_PAGEALLOC */
2665 
2666 #if MAX_NUMNODES > 1
2667 void __init setup_nr_node_ids(void);
2668 #else
2669 static inline void setup_nr_node_ids(void) {}
2670 #endif
2671 
2672 #endif /* __KERNEL__ */
2673 #endif /* _LINUX_MM_H */
2674 

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