xref: /linux-6.15/include/linux/mm.h (revision f7275650)
1 #ifndef _LINUX_MM_H
2 #define _LINUX_MM_H
3 
4 #include <linux/errno.h>
5 
6 #ifdef __KERNEL__
7 
8 #include <linux/gfp.h>
9 #include <linux/list.h>
10 #include <linux/mmdebug.h>
11 #include <linux/mmzone.h>
12 #include <linux/rbtree.h>
13 #include <linux/prio_tree.h>
14 #include <linux/debug_locks.h>
15 #include <linux/mm_types.h>
16 
17 struct mempolicy;
18 struct anon_vma;
19 struct file_ra_state;
20 struct user_struct;
21 struct writeback_control;
22 
23 #ifndef CONFIG_DISCONTIGMEM          /* Don't use mapnrs, do it properly */
24 extern unsigned long max_mapnr;
25 #endif
26 
27 extern unsigned long num_physpages;
28 extern void * high_memory;
29 extern int page_cluster;
30 
31 #ifdef CONFIG_SYSCTL
32 extern int sysctl_legacy_va_layout;
33 #else
34 #define sysctl_legacy_va_layout 0
35 #endif
36 
37 extern unsigned long mmap_min_addr;
38 
39 #include <asm/page.h>
40 #include <asm/pgtable.h>
41 #include <asm/processor.h>
42 
43 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
44 
45 /* to align the pointer to the (next) page boundary */
46 #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
47 
48 /*
49  * Linux kernel virtual memory manager primitives.
50  * The idea being to have a "virtual" mm in the same way
51  * we have a virtual fs - giving a cleaner interface to the
52  * mm details, and allowing different kinds of memory mappings
53  * (from shared memory to executable loading to arbitrary
54  * mmap() functions).
55  */
56 
57 extern struct kmem_cache *vm_area_cachep;
58 
59 /*
60  * This struct defines the per-mm list of VMAs for uClinux. If CONFIG_MMU is
61  * disabled, then there's a single shared list of VMAs maintained by the
62  * system, and mm's subscribe to these individually
63  */
64 struct vm_list_struct {
65 	struct vm_list_struct	*next;
66 	struct vm_area_struct	*vma;
67 };
68 
69 #ifndef CONFIG_MMU
70 extern struct rb_root nommu_vma_tree;
71 extern struct rw_semaphore nommu_vma_sem;
72 
73 extern unsigned int kobjsize(const void *objp);
74 #endif
75 
76 /*
77  * vm_flags in vm_area_struct, see mm_types.h.
78  */
79 #define VM_READ		0x00000001	/* currently active flags */
80 #define VM_WRITE	0x00000002
81 #define VM_EXEC		0x00000004
82 #define VM_SHARED	0x00000008
83 
84 /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
85 #define VM_MAYREAD	0x00000010	/* limits for mprotect() etc */
86 #define VM_MAYWRITE	0x00000020
87 #define VM_MAYEXEC	0x00000040
88 #define VM_MAYSHARE	0x00000080
89 
90 #define VM_GROWSDOWN	0x00000100	/* general info on the segment */
91 #define VM_GROWSUP	0x00000200
92 #define VM_PFNMAP	0x00000400	/* Page-ranges managed without "struct page", just pure PFN */
93 #define VM_DENYWRITE	0x00000800	/* ETXTBSY on write attempts.. */
94 
95 #define VM_EXECUTABLE	0x00001000
96 #define VM_LOCKED	0x00002000
97 #define VM_IO           0x00004000	/* Memory mapped I/O or similar */
98 
99 					/* Used by sys_madvise() */
100 #define VM_SEQ_READ	0x00008000	/* App will access data sequentially */
101 #define VM_RAND_READ	0x00010000	/* App will not benefit from clustered reads */
102 
103 #define VM_DONTCOPY	0x00020000      /* Do not copy this vma on fork */
104 #define VM_DONTEXPAND	0x00040000	/* Cannot expand with mremap() */
105 #define VM_RESERVED	0x00080000	/* Count as reserved_vm like IO */
106 #define VM_ACCOUNT	0x00100000	/* Is a VM accounted object */
107 #define VM_NORESERVE	0x00200000	/* should the VM suppress accounting */
108 #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
109 #define VM_NONLINEAR	0x00800000	/* Is non-linear (remap_file_pages) */
110 #define VM_MAPPED_COPY	0x01000000	/* T if mapped copy of data (nommu mmap) */
111 #define VM_INSERTPAGE	0x02000000	/* The vma has had "vm_insert_page()" done on it */
112 #define VM_ALWAYSDUMP	0x04000000	/* Always include in core dumps */
113 
114 #define VM_CAN_NONLINEAR 0x08000000	/* Has ->fault & does nonlinear pages */
115 #define VM_MIXEDMAP	0x10000000	/* Can contain "struct page" and pure PFN pages */
116 #define VM_SAO		0x20000000	/* Strong Access Ordering (powerpc) */
117 
118 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
119 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
120 #endif
121 
122 #ifdef CONFIG_STACK_GROWSUP
123 #define VM_STACK_FLAGS	(VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
124 #else
125 #define VM_STACK_FLAGS	(VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
126 #endif
127 
128 #define VM_READHINTMASK			(VM_SEQ_READ | VM_RAND_READ)
129 #define VM_ClearReadHint(v)		(v)->vm_flags &= ~VM_READHINTMASK
130 #define VM_NormalReadHint(v)		(!((v)->vm_flags & VM_READHINTMASK))
131 #define VM_SequentialReadHint(v)	((v)->vm_flags & VM_SEQ_READ)
132 #define VM_RandomReadHint(v)		((v)->vm_flags & VM_RAND_READ)
133 
134 /*
135  * mapping from the currently active vm_flags protection bits (the
136  * low four bits) to a page protection mask..
137  */
138 extern pgprot_t protection_map[16];
139 
140 #define FAULT_FLAG_WRITE	0x01	/* Fault was a write access */
141 #define FAULT_FLAG_NONLINEAR	0x02	/* Fault was via a nonlinear mapping */
142 
143 
144 /*
145  * vm_fault is filled by the the pagefault handler and passed to the vma's
146  * ->fault function. The vma's ->fault is responsible for returning a bitmask
147  * of VM_FAULT_xxx flags that give details about how the fault was handled.
148  *
149  * pgoff should be used in favour of virtual_address, if possible. If pgoff
150  * is used, one may set VM_CAN_NONLINEAR in the vma->vm_flags to get nonlinear
151  * mapping support.
152  */
153 struct vm_fault {
154 	unsigned int flags;		/* FAULT_FLAG_xxx flags */
155 	pgoff_t pgoff;			/* Logical page offset based on vma */
156 	void __user *virtual_address;	/* Faulting virtual address */
157 
158 	struct page *page;		/* ->fault handlers should return a
159 					 * page here, unless VM_FAULT_NOPAGE
160 					 * is set (which is also implied by
161 					 * VM_FAULT_ERROR).
162 					 */
163 };
164 
165 /*
166  * These are the virtual MM functions - opening of an area, closing and
167  * unmapping it (needed to keep files on disk up-to-date etc), pointer
168  * to the functions called when a no-page or a wp-page exception occurs.
169  */
170 struct vm_operations_struct {
171 	void (*open)(struct vm_area_struct * area);
172 	void (*close)(struct vm_area_struct * area);
173 	int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
174 
175 	/* notification that a previously read-only page is about to become
176 	 * writable, if an error is returned it will cause a SIGBUS */
177 	int (*page_mkwrite)(struct vm_area_struct *vma, struct page *page);
178 
179 	/* called by access_process_vm when get_user_pages() fails, typically
180 	 * for use by special VMAs that can switch between memory and hardware
181 	 */
182 	int (*access)(struct vm_area_struct *vma, unsigned long addr,
183 		      void *buf, int len, int write);
184 #ifdef CONFIG_NUMA
185 	/*
186 	 * set_policy() op must add a reference to any non-NULL @new mempolicy
187 	 * to hold the policy upon return.  Caller should pass NULL @new to
188 	 * remove a policy and fall back to surrounding context--i.e. do not
189 	 * install a MPOL_DEFAULT policy, nor the task or system default
190 	 * mempolicy.
191 	 */
192 	int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
193 
194 	/*
195 	 * get_policy() op must add reference [mpol_get()] to any policy at
196 	 * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
197 	 * in mm/mempolicy.c will do this automatically.
198 	 * get_policy() must NOT add a ref if the policy at (vma,addr) is not
199 	 * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
200 	 * If no [shared/vma] mempolicy exists at the addr, get_policy() op
201 	 * must return NULL--i.e., do not "fallback" to task or system default
202 	 * policy.
203 	 */
204 	struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
205 					unsigned long addr);
206 	int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
207 		const nodemask_t *to, unsigned long flags);
208 #endif
209 };
210 
211 struct mmu_gather;
212 struct inode;
213 
214 #define page_private(page)		((page)->private)
215 #define set_page_private(page, v)	((page)->private = (v))
216 
217 /*
218  * FIXME: take this include out, include page-flags.h in
219  * files which need it (119 of them)
220  */
221 #include <linux/page-flags.h>
222 
223 /*
224  * Methods to modify the page usage count.
225  *
226  * What counts for a page usage:
227  * - cache mapping   (page->mapping)
228  * - private data    (page->private)
229  * - page mapped in a task's page tables, each mapping
230  *   is counted separately
231  *
232  * Also, many kernel routines increase the page count before a critical
233  * routine so they can be sure the page doesn't go away from under them.
234  */
235 
236 /*
237  * Drop a ref, return true if the refcount fell to zero (the page has no users)
238  */
239 static inline int put_page_testzero(struct page *page)
240 {
241 	VM_BUG_ON(atomic_read(&page->_count) == 0);
242 	return atomic_dec_and_test(&page->_count);
243 }
244 
245 /*
246  * Try to grab a ref unless the page has a refcount of zero, return false if
247  * that is the case.
248  */
249 static inline int get_page_unless_zero(struct page *page)
250 {
251 	VM_BUG_ON(PageTail(page));
252 	return atomic_inc_not_zero(&page->_count);
253 }
254 
255 /* Support for virtually mapped pages */
256 struct page *vmalloc_to_page(const void *addr);
257 unsigned long vmalloc_to_pfn(const void *addr);
258 
259 /*
260  * Determine if an address is within the vmalloc range
261  *
262  * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
263  * is no special casing required.
264  */
265 static inline int is_vmalloc_addr(const void *x)
266 {
267 #ifdef CONFIG_MMU
268 	unsigned long addr = (unsigned long)x;
269 
270 	return addr >= VMALLOC_START && addr < VMALLOC_END;
271 #else
272 	return 0;
273 #endif
274 }
275 
276 static inline struct page *compound_head(struct page *page)
277 {
278 	if (unlikely(PageTail(page)))
279 		return page->first_page;
280 	return page;
281 }
282 
283 static inline int page_count(struct page *page)
284 {
285 	return atomic_read(&compound_head(page)->_count);
286 }
287 
288 static inline void get_page(struct page *page)
289 {
290 	page = compound_head(page);
291 	VM_BUG_ON(atomic_read(&page->_count) == 0);
292 	atomic_inc(&page->_count);
293 }
294 
295 static inline struct page *virt_to_head_page(const void *x)
296 {
297 	struct page *page = virt_to_page(x);
298 	return compound_head(page);
299 }
300 
301 /*
302  * Setup the page count before being freed into the page allocator for
303  * the first time (boot or memory hotplug)
304  */
305 static inline void init_page_count(struct page *page)
306 {
307 	atomic_set(&page->_count, 1);
308 }
309 
310 void put_page(struct page *page);
311 void put_pages_list(struct list_head *pages);
312 
313 void split_page(struct page *page, unsigned int order);
314 
315 /*
316  * Compound pages have a destructor function.  Provide a
317  * prototype for that function and accessor functions.
318  * These are _only_ valid on the head of a PG_compound page.
319  */
320 typedef void compound_page_dtor(struct page *);
321 
322 static inline void set_compound_page_dtor(struct page *page,
323 						compound_page_dtor *dtor)
324 {
325 	page[1].lru.next = (void *)dtor;
326 }
327 
328 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
329 {
330 	return (compound_page_dtor *)page[1].lru.next;
331 }
332 
333 static inline int compound_order(struct page *page)
334 {
335 	if (!PageHead(page))
336 		return 0;
337 	return (unsigned long)page[1].lru.prev;
338 }
339 
340 static inline void set_compound_order(struct page *page, unsigned long order)
341 {
342 	page[1].lru.prev = (void *)order;
343 }
344 
345 /*
346  * Multiple processes may "see" the same page. E.g. for untouched
347  * mappings of /dev/null, all processes see the same page full of
348  * zeroes, and text pages of executables and shared libraries have
349  * only one copy in memory, at most, normally.
350  *
351  * For the non-reserved pages, page_count(page) denotes a reference count.
352  *   page_count() == 0 means the page is free. page->lru is then used for
353  *   freelist management in the buddy allocator.
354  *   page_count() > 0  means the page has been allocated.
355  *
356  * Pages are allocated by the slab allocator in order to provide memory
357  * to kmalloc and kmem_cache_alloc. In this case, the management of the
358  * page, and the fields in 'struct page' are the responsibility of mm/slab.c
359  * unless a particular usage is carefully commented. (the responsibility of
360  * freeing the kmalloc memory is the caller's, of course).
361  *
362  * A page may be used by anyone else who does a __get_free_page().
363  * In this case, page_count still tracks the references, and should only
364  * be used through the normal accessor functions. The top bits of page->flags
365  * and page->virtual store page management information, but all other fields
366  * are unused and could be used privately, carefully. The management of this
367  * page is the responsibility of the one who allocated it, and those who have
368  * subsequently been given references to it.
369  *
370  * The other pages (we may call them "pagecache pages") are completely
371  * managed by the Linux memory manager: I/O, buffers, swapping etc.
372  * The following discussion applies only to them.
373  *
374  * A pagecache page contains an opaque `private' member, which belongs to the
375  * page's address_space. Usually, this is the address of a circular list of
376  * the page's disk buffers. PG_private must be set to tell the VM to call
377  * into the filesystem to release these pages.
378  *
379  * A page may belong to an inode's memory mapping. In this case, page->mapping
380  * is the pointer to the inode, and page->index is the file offset of the page,
381  * in units of PAGE_CACHE_SIZE.
382  *
383  * If pagecache pages are not associated with an inode, they are said to be
384  * anonymous pages. These may become associated with the swapcache, and in that
385  * case PG_swapcache is set, and page->private is an offset into the swapcache.
386  *
387  * In either case (swapcache or inode backed), the pagecache itself holds one
388  * reference to the page. Setting PG_private should also increment the
389  * refcount. The each user mapping also has a reference to the page.
390  *
391  * The pagecache pages are stored in a per-mapping radix tree, which is
392  * rooted at mapping->page_tree, and indexed by offset.
393  * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
394  * lists, we instead now tag pages as dirty/writeback in the radix tree.
395  *
396  * All pagecache pages may be subject to I/O:
397  * - inode pages may need to be read from disk,
398  * - inode pages which have been modified and are MAP_SHARED may need
399  *   to be written back to the inode on disk,
400  * - anonymous pages (including MAP_PRIVATE file mappings) which have been
401  *   modified may need to be swapped out to swap space and (later) to be read
402  *   back into memory.
403  */
404 
405 /*
406  * The zone field is never updated after free_area_init_core()
407  * sets it, so none of the operations on it need to be atomic.
408  */
409 
410 
411 /*
412  * page->flags layout:
413  *
414  * There are three possibilities for how page->flags get
415  * laid out.  The first is for the normal case, without
416  * sparsemem.  The second is for sparsemem when there is
417  * plenty of space for node and section.  The last is when
418  * we have run out of space and have to fall back to an
419  * alternate (slower) way of determining the node.
420  *
421  * No sparsemem or sparsemem vmemmap: |       NODE     | ZONE | ... | FLAGS |
422  * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS |
423  * classic sparse no space for node:  | SECTION |     ZONE    | ... | FLAGS |
424  */
425 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
426 #define SECTIONS_WIDTH		SECTIONS_SHIFT
427 #else
428 #define SECTIONS_WIDTH		0
429 #endif
430 
431 #define ZONES_WIDTH		ZONES_SHIFT
432 
433 #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
434 #define NODES_WIDTH		NODES_SHIFT
435 #else
436 #ifdef CONFIG_SPARSEMEM_VMEMMAP
437 #error "Vmemmap: No space for nodes field in page flags"
438 #endif
439 #define NODES_WIDTH		0
440 #endif
441 
442 /* Page flags: | [SECTION] | [NODE] | ZONE | ... | FLAGS | */
443 #define SECTIONS_PGOFF		((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
444 #define NODES_PGOFF		(SECTIONS_PGOFF - NODES_WIDTH)
445 #define ZONES_PGOFF		(NODES_PGOFF - ZONES_WIDTH)
446 
447 /*
448  * We are going to use the flags for the page to node mapping if its in
449  * there.  This includes the case where there is no node, so it is implicit.
450  */
451 #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
452 #define NODE_NOT_IN_PAGE_FLAGS
453 #endif
454 
455 #ifndef PFN_SECTION_SHIFT
456 #define PFN_SECTION_SHIFT 0
457 #endif
458 
459 /*
460  * Define the bit shifts to access each section.  For non-existant
461  * sections we define the shift as 0; that plus a 0 mask ensures
462  * the compiler will optimise away reference to them.
463  */
464 #define SECTIONS_PGSHIFT	(SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
465 #define NODES_PGSHIFT		(NODES_PGOFF * (NODES_WIDTH != 0))
466 #define ZONES_PGSHIFT		(ZONES_PGOFF * (ZONES_WIDTH != 0))
467 
468 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allcator */
469 #ifdef NODE_NOT_IN_PAGEFLAGS
470 #define ZONEID_SHIFT		(SECTIONS_SHIFT + ZONES_SHIFT)
471 #define ZONEID_PGOFF		((SECTIONS_PGOFF < ZONES_PGOFF)? \
472 						SECTIONS_PGOFF : ZONES_PGOFF)
473 #else
474 #define ZONEID_SHIFT		(NODES_SHIFT + ZONES_SHIFT)
475 #define ZONEID_PGOFF		((NODES_PGOFF < ZONES_PGOFF)? \
476 						NODES_PGOFF : ZONES_PGOFF)
477 #endif
478 
479 #define ZONEID_PGSHIFT		(ZONEID_PGOFF * (ZONEID_SHIFT != 0))
480 
481 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
482 #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
483 #endif
484 
485 #define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
486 #define NODES_MASK		((1UL << NODES_WIDTH) - 1)
487 #define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)
488 #define ZONEID_MASK		((1UL << ZONEID_SHIFT) - 1)
489 
490 static inline enum zone_type page_zonenum(struct page *page)
491 {
492 	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
493 }
494 
495 /*
496  * The identification function is only used by the buddy allocator for
497  * determining if two pages could be buddies. We are not really
498  * identifying a zone since we could be using a the section number
499  * id if we have not node id available in page flags.
500  * We guarantee only that it will return the same value for two
501  * combinable pages in a zone.
502  */
503 static inline int page_zone_id(struct page *page)
504 {
505 	return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
506 }
507 
508 static inline int zone_to_nid(struct zone *zone)
509 {
510 #ifdef CONFIG_NUMA
511 	return zone->node;
512 #else
513 	return 0;
514 #endif
515 }
516 
517 #ifdef NODE_NOT_IN_PAGE_FLAGS
518 extern int page_to_nid(struct page *page);
519 #else
520 static inline int page_to_nid(struct page *page)
521 {
522 	return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
523 }
524 #endif
525 
526 static inline struct zone *page_zone(struct page *page)
527 {
528 	return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
529 }
530 
531 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
532 static inline unsigned long page_to_section(struct page *page)
533 {
534 	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
535 }
536 #endif
537 
538 static inline void set_page_zone(struct page *page, enum zone_type zone)
539 {
540 	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
541 	page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
542 }
543 
544 static inline void set_page_node(struct page *page, unsigned long node)
545 {
546 	page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
547 	page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
548 }
549 
550 static inline void set_page_section(struct page *page, unsigned long section)
551 {
552 	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
553 	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
554 }
555 
556 static inline void set_page_links(struct page *page, enum zone_type zone,
557 	unsigned long node, unsigned long pfn)
558 {
559 	set_page_zone(page, zone);
560 	set_page_node(page, node);
561 	set_page_section(page, pfn_to_section_nr(pfn));
562 }
563 
564 /*
565  * If a hint addr is less than mmap_min_addr change hint to be as
566  * low as possible but still greater than mmap_min_addr
567  */
568 static inline unsigned long round_hint_to_min(unsigned long hint)
569 {
570 #ifdef CONFIG_SECURITY
571 	hint &= PAGE_MASK;
572 	if (((void *)hint != NULL) &&
573 	    (hint < mmap_min_addr))
574 		return PAGE_ALIGN(mmap_min_addr);
575 #endif
576 	return hint;
577 }
578 
579 /*
580  * Some inline functions in vmstat.h depend on page_zone()
581  */
582 #include <linux/vmstat.h>
583 
584 static __always_inline void *lowmem_page_address(struct page *page)
585 {
586 	return __va(page_to_pfn(page) << PAGE_SHIFT);
587 }
588 
589 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
590 #define HASHED_PAGE_VIRTUAL
591 #endif
592 
593 #if defined(WANT_PAGE_VIRTUAL)
594 #define page_address(page) ((page)->virtual)
595 #define set_page_address(page, address)			\
596 	do {						\
597 		(page)->virtual = (address);		\
598 	} while(0)
599 #define page_address_init()  do { } while(0)
600 #endif
601 
602 #if defined(HASHED_PAGE_VIRTUAL)
603 void *page_address(struct page *page);
604 void set_page_address(struct page *page, void *virtual);
605 void page_address_init(void);
606 #endif
607 
608 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
609 #define page_address(page) lowmem_page_address(page)
610 #define set_page_address(page, address)  do { } while(0)
611 #define page_address_init()  do { } while(0)
612 #endif
613 
614 /*
615  * On an anonymous page mapped into a user virtual memory area,
616  * page->mapping points to its anon_vma, not to a struct address_space;
617  * with the PAGE_MAPPING_ANON bit set to distinguish it.
618  *
619  * Please note that, confusingly, "page_mapping" refers to the inode
620  * address_space which maps the page from disk; whereas "page_mapped"
621  * refers to user virtual address space into which the page is mapped.
622  */
623 #define PAGE_MAPPING_ANON	1
624 
625 extern struct address_space swapper_space;
626 static inline struct address_space *page_mapping(struct page *page)
627 {
628 	struct address_space *mapping = page->mapping;
629 
630 	VM_BUG_ON(PageSlab(page));
631 #ifdef CONFIG_SWAP
632 	if (unlikely(PageSwapCache(page)))
633 		mapping = &swapper_space;
634 	else
635 #endif
636 	if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
637 		mapping = NULL;
638 	return mapping;
639 }
640 
641 static inline int PageAnon(struct page *page)
642 {
643 	return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
644 }
645 
646 /*
647  * Return the pagecache index of the passed page.  Regular pagecache pages
648  * use ->index whereas swapcache pages use ->private
649  */
650 static inline pgoff_t page_index(struct page *page)
651 {
652 	if (unlikely(PageSwapCache(page)))
653 		return page_private(page);
654 	return page->index;
655 }
656 
657 /*
658  * The atomic page->_mapcount, like _count, starts from -1:
659  * so that transitions both from it and to it can be tracked,
660  * using atomic_inc_and_test and atomic_add_negative(-1).
661  */
662 static inline void reset_page_mapcount(struct page *page)
663 {
664 	atomic_set(&(page)->_mapcount, -1);
665 }
666 
667 static inline int page_mapcount(struct page *page)
668 {
669 	return atomic_read(&(page)->_mapcount) + 1;
670 }
671 
672 /*
673  * Return true if this page is mapped into pagetables.
674  */
675 static inline int page_mapped(struct page *page)
676 {
677 	return atomic_read(&(page)->_mapcount) >= 0;
678 }
679 
680 /*
681  * Different kinds of faults, as returned by handle_mm_fault().
682  * Used to decide whether a process gets delivered SIGBUS or
683  * just gets major/minor fault counters bumped up.
684  */
685 
686 #define VM_FAULT_MINOR	0 /* For backwards compat. Remove me quickly. */
687 
688 #define VM_FAULT_OOM	0x0001
689 #define VM_FAULT_SIGBUS	0x0002
690 #define VM_FAULT_MAJOR	0x0004
691 #define VM_FAULT_WRITE	0x0008	/* Special case for get_user_pages */
692 
693 #define VM_FAULT_NOPAGE	0x0100	/* ->fault installed the pte, not return page */
694 #define VM_FAULT_LOCKED	0x0200	/* ->fault locked the returned page */
695 
696 #define VM_FAULT_ERROR	(VM_FAULT_OOM | VM_FAULT_SIGBUS)
697 
698 #define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
699 
700 extern void show_free_areas(void);
701 
702 #ifdef CONFIG_SHMEM
703 int shmem_lock(struct file *file, int lock, struct user_struct *user);
704 #else
705 static inline int shmem_lock(struct file *file, int lock,
706 			     struct user_struct *user)
707 {
708 	return 0;
709 }
710 #endif
711 struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
712 
713 int shmem_zero_setup(struct vm_area_struct *);
714 
715 #ifndef CONFIG_MMU
716 extern unsigned long shmem_get_unmapped_area(struct file *file,
717 					     unsigned long addr,
718 					     unsigned long len,
719 					     unsigned long pgoff,
720 					     unsigned long flags);
721 #endif
722 
723 extern int can_do_mlock(void);
724 extern int user_shm_lock(size_t, struct user_struct *);
725 extern void user_shm_unlock(size_t, struct user_struct *);
726 
727 /*
728  * Parameter block passed down to zap_pte_range in exceptional cases.
729  */
730 struct zap_details {
731 	struct vm_area_struct *nonlinear_vma;	/* Check page->index if set */
732 	struct address_space *check_mapping;	/* Check page->mapping if set */
733 	pgoff_t	first_index;			/* Lowest page->index to unmap */
734 	pgoff_t last_index;			/* Highest page->index to unmap */
735 	spinlock_t *i_mmap_lock;		/* For unmap_mapping_range: */
736 	unsigned long truncate_count;		/* Compare vm_truncate_count */
737 };
738 
739 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
740 		pte_t pte);
741 
742 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
743 		unsigned long size);
744 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
745 		unsigned long size, struct zap_details *);
746 unsigned long unmap_vmas(struct mmu_gather **tlb,
747 		struct vm_area_struct *start_vma, unsigned long start_addr,
748 		unsigned long end_addr, unsigned long *nr_accounted,
749 		struct zap_details *);
750 
751 /**
752  * mm_walk - callbacks for walk_page_range
753  * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
754  * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
755  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
756  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
757  * @pte_hole: if set, called for each hole at all levels
758  *
759  * (see walk_page_range for more details)
760  */
761 struct mm_walk {
762 	int (*pgd_entry)(pgd_t *, unsigned long, unsigned long, struct mm_walk *);
763 	int (*pud_entry)(pud_t *, unsigned long, unsigned long, struct mm_walk *);
764 	int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, struct mm_walk *);
765 	int (*pte_entry)(pte_t *, unsigned long, unsigned long, struct mm_walk *);
766 	int (*pte_hole)(unsigned long, unsigned long, struct mm_walk *);
767 	struct mm_struct *mm;
768 	void *private;
769 };
770 
771 int walk_page_range(unsigned long addr, unsigned long end,
772 		struct mm_walk *walk);
773 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
774 		unsigned long end, unsigned long floor, unsigned long ceiling);
775 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
776 			struct vm_area_struct *vma);
777 void unmap_mapping_range(struct address_space *mapping,
778 		loff_t const holebegin, loff_t const holelen, int even_cows);
779 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
780 			void *buf, int len, int write);
781 
782 static inline void unmap_shared_mapping_range(struct address_space *mapping,
783 		loff_t const holebegin, loff_t const holelen)
784 {
785 	unmap_mapping_range(mapping, holebegin, holelen, 0);
786 }
787 
788 extern int vmtruncate(struct inode * inode, loff_t offset);
789 extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
790 
791 #ifdef CONFIG_MMU
792 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
793 			unsigned long address, int write_access);
794 #else
795 static inline int handle_mm_fault(struct mm_struct *mm,
796 			struct vm_area_struct *vma, unsigned long address,
797 			int write_access)
798 {
799 	/* should never happen if there's no MMU */
800 	BUG();
801 	return VM_FAULT_SIGBUS;
802 }
803 #endif
804 
805 extern int make_pages_present(unsigned long addr, unsigned long end);
806 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
807 
808 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
809 		int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
810 
811 extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
812 extern void do_invalidatepage(struct page *page, unsigned long offset);
813 
814 int __set_page_dirty_nobuffers(struct page *page);
815 int __set_page_dirty_no_writeback(struct page *page);
816 int redirty_page_for_writepage(struct writeback_control *wbc,
817 				struct page *page);
818 int set_page_dirty(struct page *page);
819 int set_page_dirty_lock(struct page *page);
820 int clear_page_dirty_for_io(struct page *page);
821 
822 extern unsigned long move_page_tables(struct vm_area_struct *vma,
823 		unsigned long old_addr, struct vm_area_struct *new_vma,
824 		unsigned long new_addr, unsigned long len);
825 extern unsigned long do_mremap(unsigned long addr,
826 			       unsigned long old_len, unsigned long new_len,
827 			       unsigned long flags, unsigned long new_addr);
828 extern int mprotect_fixup(struct vm_area_struct *vma,
829 			  struct vm_area_struct **pprev, unsigned long start,
830 			  unsigned long end, unsigned long newflags);
831 
832 /*
833  * get_user_pages_fast provides equivalent functionality to get_user_pages,
834  * operating on current and current->mm (force=0 and doesn't return any vmas).
835  *
836  * get_user_pages_fast may take mmap_sem and page tables, so no assumptions
837  * can be made about locking. get_user_pages_fast is to be implemented in a
838  * way that is advantageous (vs get_user_pages()) when the user memory area is
839  * already faulted in and present in ptes. However if the pages have to be
840  * faulted in, it may turn out to be slightly slower).
841  */
842 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
843 			struct page **pages);
844 
845 /*
846  * A callback you can register to apply pressure to ageable caches.
847  *
848  * 'shrink' is passed a count 'nr_to_scan' and a 'gfpmask'.  It should
849  * look through the least-recently-used 'nr_to_scan' entries and
850  * attempt to free them up.  It should return the number of objects
851  * which remain in the cache.  If it returns -1, it means it cannot do
852  * any scanning at this time (eg. there is a risk of deadlock).
853  *
854  * The 'gfpmask' refers to the allocation we are currently trying to
855  * fulfil.
856  *
857  * Note that 'shrink' will be passed nr_to_scan == 0 when the VM is
858  * querying the cache size, so a fastpath for that case is appropriate.
859  */
860 struct shrinker {
861 	int (*shrink)(int nr_to_scan, gfp_t gfp_mask);
862 	int seeks;	/* seeks to recreate an obj */
863 
864 	/* These are for internal use */
865 	struct list_head list;
866 	long nr;	/* objs pending delete */
867 };
868 #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
869 extern void register_shrinker(struct shrinker *);
870 extern void unregister_shrinker(struct shrinker *);
871 
872 int vma_wants_writenotify(struct vm_area_struct *vma);
873 
874 extern pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl);
875 
876 #ifdef __PAGETABLE_PUD_FOLDED
877 static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
878 						unsigned long address)
879 {
880 	return 0;
881 }
882 #else
883 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
884 #endif
885 
886 #ifdef __PAGETABLE_PMD_FOLDED
887 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
888 						unsigned long address)
889 {
890 	return 0;
891 }
892 #else
893 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
894 #endif
895 
896 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);
897 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
898 
899 /*
900  * The following ifdef needed to get the 4level-fixup.h header to work.
901  * Remove it when 4level-fixup.h has been removed.
902  */
903 #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
904 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
905 {
906 	return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
907 		NULL: pud_offset(pgd, address);
908 }
909 
910 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
911 {
912 	return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
913 		NULL: pmd_offset(pud, address);
914 }
915 #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
916 
917 #if USE_SPLIT_PTLOCKS
918 /*
919  * We tuck a spinlock to guard each pagetable page into its struct page,
920  * at page->private, with BUILD_BUG_ON to make sure that this will not
921  * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
922  * When freeing, reset page->mapping so free_pages_check won't complain.
923  */
924 #define __pte_lockptr(page)	&((page)->ptl)
925 #define pte_lock_init(_page)	do {					\
926 	spin_lock_init(__pte_lockptr(_page));				\
927 } while (0)
928 #define pte_lock_deinit(page)	((page)->mapping = NULL)
929 #define pte_lockptr(mm, pmd)	({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
930 #else	/* !USE_SPLIT_PTLOCKS */
931 /*
932  * We use mm->page_table_lock to guard all pagetable pages of the mm.
933  */
934 #define pte_lock_init(page)	do {} while (0)
935 #define pte_lock_deinit(page)	do {} while (0)
936 #define pte_lockptr(mm, pmd)	({(void)(pmd); &(mm)->page_table_lock;})
937 #endif /* USE_SPLIT_PTLOCKS */
938 
939 static inline void pgtable_page_ctor(struct page *page)
940 {
941 	pte_lock_init(page);
942 	inc_zone_page_state(page, NR_PAGETABLE);
943 }
944 
945 static inline void pgtable_page_dtor(struct page *page)
946 {
947 	pte_lock_deinit(page);
948 	dec_zone_page_state(page, NR_PAGETABLE);
949 }
950 
951 #define pte_offset_map_lock(mm, pmd, address, ptlp)	\
952 ({							\
953 	spinlock_t *__ptl = pte_lockptr(mm, pmd);	\
954 	pte_t *__pte = pte_offset_map(pmd, address);	\
955 	*(ptlp) = __ptl;				\
956 	spin_lock(__ptl);				\
957 	__pte;						\
958 })
959 
960 #define pte_unmap_unlock(pte, ptl)	do {		\
961 	spin_unlock(ptl);				\
962 	pte_unmap(pte);					\
963 } while (0)
964 
965 #define pte_alloc_map(mm, pmd, address)			\
966 	((unlikely(!pmd_present(*(pmd))) && __pte_alloc(mm, pmd, address))? \
967 		NULL: pte_offset_map(pmd, address))
968 
969 #define pte_alloc_map_lock(mm, pmd, address, ptlp)	\
970 	((unlikely(!pmd_present(*(pmd))) && __pte_alloc(mm, pmd, address))? \
971 		NULL: pte_offset_map_lock(mm, pmd, address, ptlp))
972 
973 #define pte_alloc_kernel(pmd, address)			\
974 	((unlikely(!pmd_present(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
975 		NULL: pte_offset_kernel(pmd, address))
976 
977 extern void free_area_init(unsigned long * zones_size);
978 extern void free_area_init_node(int nid, unsigned long * zones_size,
979 		unsigned long zone_start_pfn, unsigned long *zholes_size);
980 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
981 /*
982  * With CONFIG_ARCH_POPULATES_NODE_MAP set, an architecture may initialise its
983  * zones, allocate the backing mem_map and account for memory holes in a more
984  * architecture independent manner. This is a substitute for creating the
985  * zone_sizes[] and zholes_size[] arrays and passing them to
986  * free_area_init_node()
987  *
988  * An architecture is expected to register range of page frames backed by
989  * physical memory with add_active_range() before calling
990  * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
991  * usage, an architecture is expected to do something like
992  *
993  * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
994  * 							 max_highmem_pfn};
995  * for_each_valid_physical_page_range()
996  * 	add_active_range(node_id, start_pfn, end_pfn)
997  * free_area_init_nodes(max_zone_pfns);
998  *
999  * If the architecture guarantees that there are no holes in the ranges
1000  * registered with add_active_range(), free_bootmem_active_regions()
1001  * will call free_bootmem_node() for each registered physical page range.
1002  * Similarly sparse_memory_present_with_active_regions() calls
1003  * memory_present() for each range when SPARSEMEM is enabled.
1004  *
1005  * See mm/page_alloc.c for more information on each function exposed by
1006  * CONFIG_ARCH_POPULATES_NODE_MAP
1007  */
1008 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
1009 extern void add_active_range(unsigned int nid, unsigned long start_pfn,
1010 					unsigned long end_pfn);
1011 extern void remove_active_range(unsigned int nid, unsigned long start_pfn,
1012 					unsigned long end_pfn);
1013 extern void push_node_boundaries(unsigned int nid, unsigned long start_pfn,
1014 					unsigned long end_pfn);
1015 extern void remove_all_active_ranges(void);
1016 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
1017 						unsigned long end_pfn);
1018 extern void get_pfn_range_for_nid(unsigned int nid,
1019 			unsigned long *start_pfn, unsigned long *end_pfn);
1020 extern unsigned long find_min_pfn_with_active_regions(void);
1021 extern void free_bootmem_with_active_regions(int nid,
1022 						unsigned long max_low_pfn);
1023 typedef int (*work_fn_t)(unsigned long, unsigned long, void *);
1024 extern void work_with_active_regions(int nid, work_fn_t work_fn, void *data);
1025 extern void sparse_memory_present_with_active_regions(int nid);
1026 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
1027 extern int early_pfn_to_nid(unsigned long pfn);
1028 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
1029 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
1030 extern void set_dma_reserve(unsigned long new_dma_reserve);
1031 extern void memmap_init_zone(unsigned long, int, unsigned long,
1032 				unsigned long, enum memmap_context);
1033 extern void setup_per_zone_pages_min(void);
1034 extern void mem_init(void);
1035 extern void show_mem(void);
1036 extern void si_meminfo(struct sysinfo * val);
1037 extern void si_meminfo_node(struct sysinfo *val, int nid);
1038 extern int after_bootmem;
1039 
1040 #ifdef CONFIG_NUMA
1041 extern void setup_per_cpu_pageset(void);
1042 #else
1043 static inline void setup_per_cpu_pageset(void) {}
1044 #endif
1045 
1046 /* prio_tree.c */
1047 void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
1048 void vma_prio_tree_insert(struct vm_area_struct *, struct prio_tree_root *);
1049 void vma_prio_tree_remove(struct vm_area_struct *, struct prio_tree_root *);
1050 struct vm_area_struct *vma_prio_tree_next(struct vm_area_struct *vma,
1051 	struct prio_tree_iter *iter);
1052 
1053 #define vma_prio_tree_foreach(vma, iter, root, begin, end)	\
1054 	for (prio_tree_iter_init(iter, root, begin, end), vma = NULL;	\
1055 		(vma = vma_prio_tree_next(vma, iter)); )
1056 
1057 static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
1058 					struct list_head *list)
1059 {
1060 	vma->shared.vm_set.parent = NULL;
1061 	list_add_tail(&vma->shared.vm_set.list, list);
1062 }
1063 
1064 /* mmap.c */
1065 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
1066 extern void vma_adjust(struct vm_area_struct *vma, unsigned long start,
1067 	unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
1068 extern struct vm_area_struct *vma_merge(struct mm_struct *,
1069 	struct vm_area_struct *prev, unsigned long addr, unsigned long end,
1070 	unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
1071 	struct mempolicy *);
1072 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
1073 extern int split_vma(struct mm_struct *,
1074 	struct vm_area_struct *, unsigned long addr, int new_below);
1075 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
1076 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
1077 	struct rb_node **, struct rb_node *);
1078 extern void unlink_file_vma(struct vm_area_struct *);
1079 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
1080 	unsigned long addr, unsigned long len, pgoff_t pgoff);
1081 extern void exit_mmap(struct mm_struct *);
1082 
1083 extern int mm_take_all_locks(struct mm_struct *mm);
1084 extern void mm_drop_all_locks(struct mm_struct *mm);
1085 
1086 #ifdef CONFIG_PROC_FS
1087 /* From fs/proc/base.c. callers must _not_ hold the mm's exe_file_lock */
1088 extern void added_exe_file_vma(struct mm_struct *mm);
1089 extern void removed_exe_file_vma(struct mm_struct *mm);
1090 #else
1091 static inline void added_exe_file_vma(struct mm_struct *mm)
1092 {}
1093 
1094 static inline void removed_exe_file_vma(struct mm_struct *mm)
1095 {}
1096 #endif /* CONFIG_PROC_FS */
1097 
1098 extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
1099 extern int install_special_mapping(struct mm_struct *mm,
1100 				   unsigned long addr, unsigned long len,
1101 				   unsigned long flags, struct page **pages);
1102 
1103 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1104 
1105 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
1106 	unsigned long len, unsigned long prot,
1107 	unsigned long flag, unsigned long pgoff);
1108 extern unsigned long mmap_region(struct file *file, unsigned long addr,
1109 	unsigned long len, unsigned long flags,
1110 	unsigned int vm_flags, unsigned long pgoff,
1111 	int accountable);
1112 
1113 static inline unsigned long do_mmap(struct file *file, unsigned long addr,
1114 	unsigned long len, unsigned long prot,
1115 	unsigned long flag, unsigned long offset)
1116 {
1117 	unsigned long ret = -EINVAL;
1118 	if ((offset + PAGE_ALIGN(len)) < offset)
1119 		goto out;
1120 	if (!(offset & ~PAGE_MASK))
1121 		ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
1122 out:
1123 	return ret;
1124 }
1125 
1126 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
1127 
1128 extern unsigned long do_brk(unsigned long, unsigned long);
1129 
1130 /* filemap.c */
1131 extern unsigned long page_unuse(struct page *);
1132 extern void truncate_inode_pages(struct address_space *, loff_t);
1133 extern void truncate_inode_pages_range(struct address_space *,
1134 				       loff_t lstart, loff_t lend);
1135 
1136 /* generic vm_area_ops exported for stackable file systems */
1137 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
1138 
1139 /* mm/page-writeback.c */
1140 int write_one_page(struct page *page, int wait);
1141 
1142 /* readahead.c */
1143 #define VM_MAX_READAHEAD	128	/* kbytes */
1144 #define VM_MIN_READAHEAD	16	/* kbytes (includes current page) */
1145 
1146 int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
1147 			pgoff_t offset, unsigned long nr_to_read);
1148 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
1149 			pgoff_t offset, unsigned long nr_to_read);
1150 
1151 void page_cache_sync_readahead(struct address_space *mapping,
1152 			       struct file_ra_state *ra,
1153 			       struct file *filp,
1154 			       pgoff_t offset,
1155 			       unsigned long size);
1156 
1157 void page_cache_async_readahead(struct address_space *mapping,
1158 				struct file_ra_state *ra,
1159 				struct file *filp,
1160 				struct page *pg,
1161 				pgoff_t offset,
1162 				unsigned long size);
1163 
1164 unsigned long max_sane_readahead(unsigned long nr);
1165 
1166 /* Do stack extension */
1167 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
1168 #ifdef CONFIG_IA64
1169 extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
1170 #endif
1171 extern int expand_stack_downwards(struct vm_area_struct *vma,
1172 				  unsigned long address);
1173 
1174 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
1175 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
1176 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
1177 					     struct vm_area_struct **pprev);
1178 
1179 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
1180    NULL if none.  Assume start_addr < end_addr. */
1181 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
1182 {
1183 	struct vm_area_struct * vma = find_vma(mm,start_addr);
1184 
1185 	if (vma && end_addr <= vma->vm_start)
1186 		vma = NULL;
1187 	return vma;
1188 }
1189 
1190 static inline unsigned long vma_pages(struct vm_area_struct *vma)
1191 {
1192 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
1193 }
1194 
1195 pgprot_t vm_get_page_prot(unsigned long vm_flags);
1196 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
1197 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
1198 			unsigned long pfn, unsigned long size, pgprot_t);
1199 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
1200 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1201 			unsigned long pfn);
1202 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1203 			unsigned long pfn);
1204 
1205 struct page *follow_page(struct vm_area_struct *, unsigned long address,
1206 			unsigned int foll_flags);
1207 #define FOLL_WRITE	0x01	/* check pte is writable */
1208 #define FOLL_TOUCH	0x02	/* mark page accessed */
1209 #define FOLL_GET	0x04	/* do get_page on page */
1210 #define FOLL_ANON	0x08	/* give ZERO_PAGE if no pgtable */
1211 
1212 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
1213 			void *data);
1214 extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
1215 			       unsigned long size, pte_fn_t fn, void *data);
1216 
1217 #ifdef CONFIG_PROC_FS
1218 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
1219 #else
1220 static inline void vm_stat_account(struct mm_struct *mm,
1221 			unsigned long flags, struct file *file, long pages)
1222 {
1223 }
1224 #endif /* CONFIG_PROC_FS */
1225 
1226 #ifdef CONFIG_DEBUG_PAGEALLOC
1227 extern int debug_pagealloc_enabled;
1228 
1229 extern void kernel_map_pages(struct page *page, int numpages, int enable);
1230 
1231 static inline void enable_debug_pagealloc(void)
1232 {
1233 	debug_pagealloc_enabled = 1;
1234 }
1235 #ifdef CONFIG_HIBERNATION
1236 extern bool kernel_page_present(struct page *page);
1237 #endif /* CONFIG_HIBERNATION */
1238 #else
1239 static inline void
1240 kernel_map_pages(struct page *page, int numpages, int enable) {}
1241 static inline void enable_debug_pagealloc(void)
1242 {
1243 }
1244 #ifdef CONFIG_HIBERNATION
1245 static inline bool kernel_page_present(struct page *page) { return true; }
1246 #endif /* CONFIG_HIBERNATION */
1247 #endif
1248 
1249 extern struct vm_area_struct *get_gate_vma(struct task_struct *tsk);
1250 #ifdef	__HAVE_ARCH_GATE_AREA
1251 int in_gate_area_no_task(unsigned long addr);
1252 int in_gate_area(struct task_struct *task, unsigned long addr);
1253 #else
1254 int in_gate_area_no_task(unsigned long addr);
1255 #define in_gate_area(task, addr) ({(void)task; in_gate_area_no_task(addr);})
1256 #endif	/* __HAVE_ARCH_GATE_AREA */
1257 
1258 int drop_caches_sysctl_handler(struct ctl_table *, int, struct file *,
1259 					void __user *, size_t *, loff_t *);
1260 unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
1261 			unsigned long lru_pages);
1262 
1263 #ifndef CONFIG_MMU
1264 #define randomize_va_space 0
1265 #else
1266 extern int randomize_va_space;
1267 #endif
1268 
1269 const char * arch_vma_name(struct vm_area_struct *vma);
1270 void print_vma_addr(char *prefix, unsigned long rip);
1271 
1272 struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
1273 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
1274 pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
1275 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
1276 pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
1277 void *vmemmap_alloc_block(unsigned long size, int node);
1278 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
1279 int vmemmap_populate_basepages(struct page *start_page,
1280 						unsigned long pages, int node);
1281 int vmemmap_populate(struct page *start_page, unsigned long pages, int node);
1282 void vmemmap_populate_print_last(void);
1283 
1284 #endif /* __KERNEL__ */
1285 #endif /* _LINUX_MM_H */
1286