Line data Source code
1 : #ifndef _LINUX_PAGEMAP_H
2 : #define _LINUX_PAGEMAP_H
3 :
4 : /*
5 : * Copyright 1995 Linus Torvalds
6 : */
7 : #include <linux/mm.h>
8 : #include <linux/fs.h>
9 : #include <linux/list.h>
10 : #include <linux/highmem.h>
11 : #include <linux/compiler.h>
12 : #include <asm/uaccess.h>
13 : #include <linux/gfp.h>
14 : #include <linux/bitops.h>
15 : #include <linux/hardirq.h> /* for in_interrupt() */
16 : #include <linux/hugetlb_inline.h>
17 :
18 : /*
19 : * Bits in mapping->flags. The lower __GFP_BITS_SHIFT bits are the page
20 : * allocation mode flags.
21 : */
22 : enum mapping_flags {
23 : AS_EIO = __GFP_BITS_SHIFT + 0, /* IO error on async write */
24 : AS_ENOSPC = __GFP_BITS_SHIFT + 1, /* ENOSPC on async write */
25 : AS_MM_ALL_LOCKS = __GFP_BITS_SHIFT + 2, /* under mm_take_all_locks() */
26 : AS_UNEVICTABLE = __GFP_BITS_SHIFT + 3, /* e.g., ramdisk, SHM_LOCK */
27 : AS_BALLOON_MAP = __GFP_BITS_SHIFT + 4, /* balloon page special map */
28 : AS_EXITING = __GFP_BITS_SHIFT + 5, /* final truncate in progress */
29 : };
30 :
31 0 : static inline void mapping_set_error(struct address_space *mapping, int error)
32 : {
33 0 : if (unlikely(error)) {
34 0 : if (error == -ENOSPC)
35 : set_bit(AS_ENOSPC, &mapping->flags);
36 : else
37 : set_bit(AS_EIO, &mapping->flags);
38 : }
39 0 : }
40 :
41 : static inline void mapping_set_unevictable(struct address_space *mapping)
42 : {
43 : set_bit(AS_UNEVICTABLE, &mapping->flags);
44 : }
45 :
46 : static inline void mapping_clear_unevictable(struct address_space *mapping)
47 : {
48 : clear_bit(AS_UNEVICTABLE, &mapping->flags);
49 : }
50 :
51 : static inline int mapping_unevictable(struct address_space *mapping)
52 : {
53 : if (mapping)
54 : return test_bit(AS_UNEVICTABLE, &mapping->flags);
55 : return !!mapping;
56 : }
57 :
58 : static inline void mapping_set_balloon(struct address_space *mapping)
59 : {
60 : set_bit(AS_BALLOON_MAP, &mapping->flags);
61 : }
62 :
63 : static inline void mapping_clear_balloon(struct address_space *mapping)
64 : {
65 : clear_bit(AS_BALLOON_MAP, &mapping->flags);
66 : }
67 :
68 : static inline int mapping_balloon(struct address_space *mapping)
69 : {
70 : return mapping && test_bit(AS_BALLOON_MAP, &mapping->flags);
71 : }
72 :
73 : static inline void mapping_set_exiting(struct address_space *mapping)
74 : {
75 : set_bit(AS_EXITING, &mapping->flags);
76 : }
77 :
78 : static inline int mapping_exiting(struct address_space *mapping)
79 : {
80 : return test_bit(AS_EXITING, &mapping->flags);
81 : }
82 :
83 : static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
84 : {
85 130439 : return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
86 : }
87 :
88 : /*
89 : * This is non-atomic. Only to be used before the mapping is activated.
90 : * Probably needs a barrier...
91 : */
92 : static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
93 : {
94 851 : m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) |
95 315 : (__force unsigned long)mask;
96 : }
97 :
98 : /*
99 : * The page cache can done in larger chunks than
100 : * one page, because it allows for more efficient
101 : * throughput (it can then be mapped into user
102 : * space in smaller chunks for same flexibility).
103 : *
104 : * Or rather, it _will_ be done in larger chunks.
105 : */
106 : #define PAGE_CACHE_SHIFT PAGE_SHIFT
107 : #define PAGE_CACHE_SIZE PAGE_SIZE
108 : #define PAGE_CACHE_MASK PAGE_MASK
109 : #define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
110 :
111 : #define page_cache_get(page) get_page(page)
112 : #define page_cache_release(page) put_page(page)
113 : void release_pages(struct page **pages, int nr, bool cold);
114 :
115 : /*
116 : * speculatively take a reference to a page.
117 : * If the page is free (_count == 0), then _count is untouched, and 0
118 : * is returned. Otherwise, _count is incremented by 1 and 1 is returned.
119 : *
120 : * This function must be called inside the same rcu_read_lock() section as has
121 : * been used to lookup the page in the pagecache radix-tree (or page table):
122 : * this allows allocators to use a synchronize_rcu() to stabilize _count.
123 : *
124 : * Unless an RCU grace period has passed, the count of all pages coming out
125 : * of the allocator must be considered unstable. page_count may return higher
126 : * than expected, and put_page must be able to do the right thing when the
127 : * page has been finished with, no matter what it is subsequently allocated
128 : * for (because put_page is what is used here to drop an invalid speculative
129 : * reference).
130 : *
131 : * This is the interesting part of the lockless pagecache (and lockless
132 : * get_user_pages) locking protocol, where the lookup-side (eg. find_get_page)
133 : * has the following pattern:
134 : * 1. find page in radix tree
135 : * 2. conditionally increment refcount
136 : * 3. check the page is still in pagecache (if no, goto 1)
137 : *
138 : * Remove-side that cares about stability of _count (eg. reclaim) has the
139 : * following (with tree_lock held for write):
140 : * A. atomically check refcount is correct and set it to 0 (atomic_cmpxchg)
141 : * B. remove page from pagecache
142 : * C. free the page
143 : *
144 : * There are 2 critical interleavings that matter:
145 : * - 2 runs before A: in this case, A sees elevated refcount and bails out
146 : * - A runs before 2: in this case, 2 sees zero refcount and retries;
147 : * subsequently, B will complete and 1 will find no page, causing the
148 : * lookup to return NULL.
149 : *
150 : * It is possible that between 1 and 2, the page is removed then the exact same
151 : * page is inserted into the same position in pagecache. That's OK: the
152 : * old find_get_page using tree_lock could equally have run before or after
153 : * such a re-insertion, depending on order that locks are granted.
154 : *
155 : * Lookups racing against pagecache insertion isn't a big problem: either 1
156 : * will find the page or it will not. Likewise, the old find_get_page could run
157 : * either before the insertion or afterwards, depending on timing.
158 : */
159 34 : static inline int page_cache_get_speculative(struct page *page)
160 : {
161 34 : VM_BUG_ON(in_interrupt());
162 :
163 : #ifdef CONFIG_TINY_RCU
164 : # ifdef CONFIG_PREEMPT_COUNT
165 : VM_BUG_ON(!in_atomic());
166 : # endif
167 : /*
168 : * Preempt must be disabled here - we rely on rcu_read_lock doing
169 : * this for us.
170 : *
171 : * Pagecache won't be truncated from interrupt context, so if we have
172 : * found a page in the radix tree here, we have pinned its refcount by
173 : * disabling preempt, and hence no need for the "speculative get" that
174 : * SMP requires.
175 : */
176 : VM_BUG_ON_PAGE(page_count(page) == 0, page);
177 : atomic_inc(&page->_count);
178 :
179 : #else
180 34 : if (unlikely(!get_page_unless_zero(page))) {
181 : /*
182 : * Either the page has been freed, or will be freed.
183 : * In either case, retry here and the caller should
184 : * do the right thing (see comments above).
185 : */
186 : return 0;
187 : }
188 : #endif
189 34 : VM_BUG_ON_PAGE(PageTail(page), page);
190 :
191 : return 1;
192 : }
193 :
194 : /*
195 : * Same as above, but add instead of inc (could just be merged)
196 : */
197 : static inline int page_cache_add_speculative(struct page *page, int count)
198 : {
199 : VM_BUG_ON(in_interrupt());
200 :
201 : #if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
202 : # ifdef CONFIG_PREEMPT_COUNT
203 : VM_BUG_ON(!in_atomic());
204 : # endif
205 : VM_BUG_ON_PAGE(page_count(page) == 0, page);
206 : atomic_add(count, &page->_count);
207 :
208 : #else
209 : if (unlikely(!atomic_add_unless(&page->_count, count, 0)))
210 : return 0;
211 : #endif
212 : VM_BUG_ON_PAGE(PageCompound(page) && page != compound_head(page), page);
213 :
214 : return 1;
215 : }
216 :
217 : static inline int page_freeze_refs(struct page *page, int count)
218 : {
219 : return likely(atomic_cmpxchg(&page->_count, count, 0) == count);
220 : }
221 :
222 : static inline void page_unfreeze_refs(struct page *page, int count)
223 : {
224 : VM_BUG_ON_PAGE(page_count(page) != 0, page);
225 : VM_BUG_ON(count == 0);
226 :
227 : atomic_set(&page->_count, count);
228 : }
229 :
230 : #ifdef CONFIG_NUMA
231 : extern struct page *__page_cache_alloc(gfp_t gfp);
232 : #else
233 : static inline struct page *__page_cache_alloc(gfp_t gfp)
234 : {
235 : return alloc_pages(gfp, 0);
236 : }
237 : #endif
238 :
239 : static inline struct page *page_cache_alloc(struct address_space *x)
240 : {
241 : return __page_cache_alloc(mapping_gfp_mask(x));
242 : }
243 :
244 : static inline struct page *page_cache_alloc_cold(struct address_space *x)
245 : {
246 : return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD);
247 : }
248 :
249 : static inline struct page *page_cache_alloc_readahead(struct address_space *x)
250 : {
251 : return __page_cache_alloc(mapping_gfp_mask(x) |
252 : __GFP_COLD | __GFP_NORETRY | __GFP_NOWARN);
253 : }
254 :
255 : typedef int filler_t(void *, struct page *);
256 :
257 : pgoff_t page_cache_next_hole(struct address_space *mapping,
258 : pgoff_t index, unsigned long max_scan);
259 : pgoff_t page_cache_prev_hole(struct address_space *mapping,
260 : pgoff_t index, unsigned long max_scan);
261 :
262 : #define FGP_ACCESSED 0x00000001
263 : #define FGP_LOCK 0x00000002
264 : #define FGP_CREAT 0x00000004
265 : #define FGP_WRITE 0x00000008
266 : #define FGP_NOFS 0x00000010
267 : #define FGP_NOWAIT 0x00000020
268 :
269 : struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
270 : int fgp_flags, gfp_t cache_gfp_mask, gfp_t radix_gfp_mask);
271 :
272 : /**
273 : * find_get_page - find and get a page reference
274 : * @mapping: the address_space to search
275 : * @offset: the page index
276 : *
277 : * Looks up the page cache slot at @mapping & @offset. If there is a
278 : * page cache page, it is returned with an increased refcount.
279 : *
280 : * Otherwise, %NULL is returned.
281 : */
282 : static inline struct page *find_get_page(struct address_space *mapping,
283 : pgoff_t offset)
284 : {
285 1320080 : return pagecache_get_page(mapping, offset, 0, 0, 0);
286 : }
287 :
288 : static inline struct page *find_get_page_flags(struct address_space *mapping,
289 : pgoff_t offset, int fgp_flags)
290 : {
291 : return pagecache_get_page(mapping, offset, fgp_flags, 0, 0);
292 : }
293 :
294 : /**
295 : * find_lock_page - locate, pin and lock a pagecache page
296 : * pagecache_get_page - find and get a page reference
297 : * @mapping: the address_space to search
298 : * @offset: the page index
299 : *
300 : * Looks up the page cache slot at @mapping & @offset. If there is a
301 : * page cache page, it is returned locked and with an increased
302 : * refcount.
303 : *
304 : * Otherwise, %NULL is returned.
305 : *
306 : * find_lock_page() may sleep.
307 : */
308 : static inline struct page *find_lock_page(struct address_space *mapping,
309 : pgoff_t offset)
310 : {
311 1276 : return pagecache_get_page(mapping, offset, FGP_LOCK, 0, 0);
312 : }
313 :
314 : /**
315 : * find_or_create_page - locate or add a pagecache page
316 : * @mapping: the page's address_space
317 : * @index: the page's index into the mapping
318 : * @gfp_mask: page allocation mode
319 : *
320 : * Looks up the page cache slot at @mapping & @offset. If there is a
321 : * page cache page, it is returned locked and with an increased
322 : * refcount.
323 : *
324 : * If the page is not present, a new page is allocated using @gfp_mask
325 : * and added to the page cache and the VM's LRU list. The page is
326 : * returned locked and with an increased refcount.
327 : *
328 : * On memory exhaustion, %NULL is returned.
329 : *
330 : * find_or_create_page() may sleep, even if @gfp_flags specifies an
331 : * atomic allocation!
332 : */
333 : static inline struct page *find_or_create_page(struct address_space *mapping,
334 : pgoff_t offset, gfp_t gfp_mask)
335 : {
336 1568484 : return pagecache_get_page(mapping, offset,
337 : FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
338 : gfp_mask, gfp_mask & GFP_RECLAIM_MASK);
339 : }
340 :
341 : /**
342 : * grab_cache_page_nowait - returns locked page at given index in given cache
343 : * @mapping: target address_space
344 : * @index: the page index
345 : *
346 : * Same as grab_cache_page(), but do not wait if the page is unavailable.
347 : * This is intended for speculative data generators, where the data can
348 : * be regenerated if the page couldn't be grabbed. This routine should
349 : * be safe to call while holding the lock for another page.
350 : *
351 : * Clear __GFP_FS when allocating the page to avoid recursion into the fs
352 : * and deadlock against the caller's locked page.
353 : */
354 : static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
355 : pgoff_t index)
356 : {
357 : return pagecache_get_page(mapping, index,
358 : FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
359 : mapping_gfp_mask(mapping),
360 : GFP_NOFS);
361 : }
362 :
363 : struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
364 : struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
365 : unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
366 : unsigned int nr_entries, struct page **entries,
367 : pgoff_t *indices);
368 : unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
369 : unsigned int nr_pages, struct page **pages);
370 : unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
371 : unsigned int nr_pages, struct page **pages);
372 : unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
373 : int tag, unsigned int nr_pages, struct page **pages);
374 :
375 : struct page *grab_cache_page_write_begin(struct address_space *mapping,
376 : pgoff_t index, unsigned flags);
377 :
378 : /*
379 : * Returns locked page at given index in given cache, creating it if needed.
380 : */
381 0 : static inline struct page *grab_cache_page(struct address_space *mapping,
382 : pgoff_t index)
383 : {
384 0 : return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
385 : }
386 :
387 : extern struct page * read_cache_page(struct address_space *mapping,
388 : pgoff_t index, filler_t *filler, void *data);
389 : extern struct page * read_cache_page_gfp(struct address_space *mapping,
390 : pgoff_t index, gfp_t gfp_mask);
391 : extern int read_cache_pages(struct address_space *mapping,
392 : struct list_head *pages, filler_t *filler, void *data);
393 :
394 : static inline struct page *read_mapping_page(struct address_space *mapping,
395 : pgoff_t index, void *data)
396 : {
397 : filler_t *filler = (filler_t *)mapping->a_ops->readpage;
398 : return read_cache_page(mapping, index, filler, data);
399 : }
400 :
401 : /*
402 : * Get the offset in PAGE_SIZE.
403 : * (TODO: hugepage should have ->index in PAGE_SIZE)
404 : */
405 : static inline pgoff_t page_to_pgoff(struct page *page)
406 : {
407 : if (unlikely(PageHeadHuge(page)))
408 : return page->index << compound_order(page);
409 : else
410 : return page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
411 : }
412 :
413 : /*
414 : * Return byte-offset into filesystem object for page.
415 : */
416 : static inline loff_t page_offset(struct page *page)
417 : {
418 8692269 : return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
419 : }
420 :
421 : static inline loff_t page_file_offset(struct page *page)
422 : {
423 : return ((loff_t)page_file_index(page)) << PAGE_CACHE_SHIFT;
424 : }
425 :
426 : extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
427 : unsigned long address);
428 :
429 : static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
430 : unsigned long address)
431 : {
432 : pgoff_t pgoff;
433 : if (unlikely(is_vm_hugetlb_page(vma)))
434 : return linear_hugepage_index(vma, address);
435 : pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
436 : pgoff += vma->vm_pgoff;
437 : return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT);
438 : }
439 :
440 : extern void __lock_page(struct page *page);
441 : extern int __lock_page_killable(struct page *page);
442 : extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
443 : unsigned int flags);
444 : extern void unlock_page(struct page *page);
445 :
446 : static inline void __set_page_locked(struct page *page)
447 : {
448 : __set_bit(PG_locked, &page->flags);
449 : }
450 :
451 : static inline void __clear_page_locked(struct page *page)
452 : {
453 : __clear_bit(PG_locked, &page->flags);
454 : }
455 :
456 : static inline int trylock_page(struct page *page)
457 : {
458 5647383 : return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
459 : }
460 :
461 : /*
462 : * lock_page may only be called if we have the page's inode pinned.
463 : */
464 1332190 : static inline void lock_page(struct page *page)
465 : {
466 1332190 : might_sleep();
467 1332195 : if (!trylock_page(page))
468 1176 : __lock_page(page);
469 1332195 : }
470 :
471 : /*
472 : * lock_page_killable is like lock_page but can be interrupted by fatal
473 : * signals. It returns 0 if it locked the page and -EINTR if it was
474 : * killed while waiting.
475 : */
476 : static inline int lock_page_killable(struct page *page)
477 : {
478 : might_sleep();
479 : if (!trylock_page(page))
480 : return __lock_page_killable(page);
481 : return 0;
482 : }
483 :
484 : /*
485 : * lock_page_or_retry - Lock the page, unless this would block and the
486 : * caller indicated that it can handle a retry.
487 : *
488 : * Return value and mmap_sem implications depend on flags; see
489 : * __lock_page_or_retry().
490 : */
491 : static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm,
492 : unsigned int flags)
493 : {
494 : might_sleep();
495 : return trylock_page(page) || __lock_page_or_retry(page, mm, flags);
496 : }
497 :
498 : /*
499 : * This is exported only for wait_on_page_locked/wait_on_page_writeback.
500 : * Never use this directly!
501 : */
502 : extern void wait_on_page_bit(struct page *page, int bit_nr);
503 :
504 : extern int wait_on_page_bit_killable(struct page *page, int bit_nr);
505 :
506 : static inline int wait_on_page_locked_killable(struct page *page)
507 : {
508 : if (PageLocked(page))
509 : return wait_on_page_bit_killable(page, PG_locked);
510 : return 0;
511 : }
512 :
513 : /*
514 : * Wait for a page to be unlocked.
515 : *
516 : * This must be called with the caller "holding" the page,
517 : * ie with increased "page->count" so that the page won't
518 : * go away during the wait..
519 : */
520 : static inline void wait_on_page_locked(struct page *page)
521 : {
522 7485 : if (PageLocked(page))
523 2518 : wait_on_page_bit(page, PG_locked);
524 : }
525 :
526 : /*
527 : * Wait for a page to complete writeback
528 : */
529 3116974 : static inline void wait_on_page_writeback(struct page *page)
530 : {
531 3116974 : if (PageWriteback(page))
532 62 : wait_on_page_bit(page, PG_writeback);
533 3116974 : }
534 :
535 : extern void end_page_writeback(struct page *page);
536 : void wait_for_stable_page(struct page *page);
537 :
538 : void page_endio(struct page *page, int rw, int err);
539 :
540 : /*
541 : * Add an arbitrary waiter to a page's wait queue
542 : */
543 : extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter);
544 :
545 : /*
546 : * Fault a userspace page into pagetables. Return non-zero on a fault.
547 : *
548 : * This assumes that two userspace pages are always sufficient. That's
549 : * not true if PAGE_CACHE_SIZE > PAGE_SIZE.
550 : */
551 : static inline int fault_in_pages_writeable(char __user *uaddr, int size)
552 : {
553 : int ret;
554 :
555 : if (unlikely(size == 0))
556 : return 0;
557 :
558 : /*
559 : * Writing zeroes into userspace here is OK, because we know that if
560 : * the zero gets there, we'll be overwriting it.
561 : */
562 : ret = __put_user(0, uaddr);
563 : if (ret == 0) {
564 : char __user *end = uaddr + size - 1;
565 :
566 : /*
567 : * If the page was already mapped, this will get a cache miss
568 : * for sure, so try to avoid doing it.
569 : */
570 : if (((unsigned long)uaddr & PAGE_MASK) !=
571 : ((unsigned long)end & PAGE_MASK))
572 : ret = __put_user(0, end);
573 : }
574 : return ret;
575 : }
576 :
577 : static inline int fault_in_pages_readable(const char __user *uaddr, int size)
578 : {
579 : volatile char c;
580 : int ret;
581 :
582 : if (unlikely(size == 0))
583 : return 0;
584 :
585 : ret = __get_user(c, uaddr);
586 : if (ret == 0) {
587 : const char __user *end = uaddr + size - 1;
588 :
589 : if (((unsigned long)uaddr & PAGE_MASK) !=
590 : ((unsigned long)end & PAGE_MASK)) {
591 : ret = __get_user(c, end);
592 : (void)c;
593 : }
594 : }
595 : return ret;
596 : }
597 :
598 : /*
599 : * Multipage variants of the above prefault helpers, useful if more than
600 : * PAGE_SIZE of data needs to be prefaulted. These are separate from the above
601 : * functions (which only handle up to PAGE_SIZE) to avoid clobbering the
602 : * filemap.c hotpaths.
603 : */
604 : static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
605 : {
606 : int ret = 0;
607 : char __user *end = uaddr + size - 1;
608 :
609 : if (unlikely(size == 0))
610 : return ret;
611 :
612 : /*
613 : * Writing zeroes into userspace here is OK, because we know that if
614 : * the zero gets there, we'll be overwriting it.
615 : */
616 : while (uaddr <= end) {
617 : ret = __put_user(0, uaddr);
618 : if (ret != 0)
619 : return ret;
620 : uaddr += PAGE_SIZE;
621 : }
622 :
623 : /* Check whether the range spilled into the next page. */
624 : if (((unsigned long)uaddr & PAGE_MASK) ==
625 : ((unsigned long)end & PAGE_MASK))
626 : ret = __put_user(0, end);
627 :
628 : return ret;
629 : }
630 :
631 : static inline int fault_in_multipages_readable(const char __user *uaddr,
632 : int size)
633 : {
634 : volatile char c;
635 : int ret = 0;
636 : const char __user *end = uaddr + size - 1;
637 :
638 : if (unlikely(size == 0))
639 : return ret;
640 :
641 : while (uaddr <= end) {
642 : ret = __get_user(c, uaddr);
643 : if (ret != 0)
644 : return ret;
645 : uaddr += PAGE_SIZE;
646 : }
647 :
648 : /* Check whether the range spilled into the next page. */
649 : if (((unsigned long)uaddr & PAGE_MASK) ==
650 : ((unsigned long)end & PAGE_MASK)) {
651 : ret = __get_user(c, end);
652 : (void)c;
653 : }
654 :
655 : return ret;
656 : }
657 :
658 : int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
659 : pgoff_t index, gfp_t gfp_mask);
660 : int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
661 : pgoff_t index, gfp_t gfp_mask);
662 : extern void delete_from_page_cache(struct page *page);
663 : extern void __delete_from_page_cache(struct page *page, void *shadow);
664 : int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
665 :
666 : /*
667 : * Like add_to_page_cache_locked, but used to add newly allocated pages:
668 : * the page is new, so we can just run __set_page_locked() against it.
669 : */
670 : static inline int add_to_page_cache(struct page *page,
671 : struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask)
672 : {
673 : int error;
674 :
675 : __set_page_locked(page);
676 : error = add_to_page_cache_locked(page, mapping, offset, gfp_mask);
677 : if (unlikely(error))
678 : __clear_page_locked(page);
679 : return error;
680 : }
681 :
682 : #endif /* _LINUX_PAGEMAP_H */
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