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1 : : /* SPDX-License-Identifier: GPL-2.0 */
2 : : #ifndef _LINUX_PAGEMAP_H
3 : : #define _LINUX_PAGEMAP_H
4 : :
5 : : /*
6 : : * Copyright 1995 Linus Torvalds
7 : : */
8 : : #include <linux/mm.h>
9 : : #include <linux/fs.h>
10 : : #include <linux/list.h>
11 : : #include <linux/highmem.h>
12 : : #include <linux/compiler.h>
13 : : #include <linux/uaccess.h>
14 : : #include <linux/gfp.h>
15 : : #include <linux/bitops.h>
16 : : #include <linux/hardirq.h> /* for in_interrupt() */
17 : : #include <linux/hugetlb_inline.h>
18 : :
19 : : struct pagevec;
20 : :
21 : : /*
22 : : * Bits in mapping->flags.
23 : : */
24 : : enum mapping_flags {
25 : : AS_EIO = 0, /* IO error on async write */
26 : : AS_ENOSPC = 1, /* ENOSPC on async write */
27 : : AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */
28 : : AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */
29 : : AS_EXITING = 4, /* final truncate in progress */
30 : : /* writeback related tags are not used */
31 : : AS_NO_WRITEBACK_TAGS = 5,
32 : : };
33 : :
34 : : /**
35 : : * mapping_set_error - record a writeback error in the address_space
36 : : * @mapping - the mapping in which an error should be set
37 : : * @error - the error to set in the mapping
38 : : *
39 : : * When writeback fails in some way, we must record that error so that
40 : : * userspace can be informed when fsync and the like are called. We endeavor
41 : : * to report errors on any file that was open at the time of the error. Some
42 : : * internal callers also need to know when writeback errors have occurred.
43 : : *
44 : : * When a writeback error occurs, most filesystems will want to call
45 : : * mapping_set_error to record the error in the mapping so that it can be
46 : : * reported when the application calls fsync(2).
47 : : */
48 : 0 : static inline void mapping_set_error(struct address_space *mapping, int error)
49 : : {
50 [ # # ]: 0 : if (likely(!error))
51 : : return;
52 : :
53 : : /* Record in wb_err for checkers using errseq_t based tracking */
54 [ # # ]: 0 : filemap_set_wb_err(mapping, error);
55 : :
56 : : /* Record it in flags for now, for legacy callers */
57 [ # # ]: 0 : if (error == -ENOSPC)
58 : 0 : set_bit(AS_ENOSPC, &mapping->flags);
59 : : else
60 : 0 : set_bit(AS_EIO, &mapping->flags);
61 : : }
62 : :
63 : 77 : static inline void mapping_set_unevictable(struct address_space *mapping)
64 : : {
65 : 77 : set_bit(AS_UNEVICTABLE, &mapping->flags);
66 : 0 : }
67 : :
68 : 0 : static inline void mapping_clear_unevictable(struct address_space *mapping)
69 : : {
70 : 0 : clear_bit(AS_UNEVICTABLE, &mapping->flags);
71 : 0 : }
72 : :
73 : 532198 : static inline int mapping_unevictable(struct address_space *mapping)
74 : : {
75 [ + + ]: 532198 : if (mapping)
76 : 133109 : return test_bit(AS_UNEVICTABLE, &mapping->flags);
77 : : return !!mapping;
78 : : }
79 : :
80 : 18670 : static inline void mapping_set_exiting(struct address_space *mapping)
81 : : {
82 : 18670 : set_bit(AS_EXITING, &mapping->flags);
83 : : }
84 : :
85 : 0 : static inline int mapping_exiting(struct address_space *mapping)
86 : : {
87 : 0 : return test_bit(AS_EXITING, &mapping->flags);
88 : : }
89 : :
90 : 0 : static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
91 : : {
92 : 0 : set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
93 : : }
94 : :
95 : 176 : static inline int mapping_use_writeback_tags(struct address_space *mapping)
96 : : {
97 [ + - + - ]: 176 : return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
98 : : }
99 : :
100 : 964905 : static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
101 : : {
102 [ - + # # ]: 964861 : return mapping->gfp_mask;
103 : : }
104 : :
105 : : /* Restricts the given gfp_mask to what the mapping allows. */
106 : 10023 : static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
107 : : gfp_t gfp_mask)
108 : : {
109 [ # # ]: 10023 : return mapping_gfp_mask(mapping) & gfp_mask;
110 : : }
111 : :
112 : : /*
113 : : * This is non-atomic. Only to be used before the mapping is activated.
114 : : * Probably needs a barrier...
115 : : */
116 : 222737 : static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
117 : : {
118 [ # # ]: 221351 : m->gfp_mask = mask;
119 : : }
120 : :
121 : : void release_pages(struct page **pages, int nr);
122 : :
123 : : /*
124 : : * speculatively take a reference to a page.
125 : : * If the page is free (_refcount == 0), then _refcount is untouched, and 0
126 : : * is returned. Otherwise, _refcount is incremented by 1 and 1 is returned.
127 : : *
128 : : * This function must be called inside the same rcu_read_lock() section as has
129 : : * been used to lookup the page in the pagecache radix-tree (or page table):
130 : : * this allows allocators to use a synchronize_rcu() to stabilize _refcount.
131 : : *
132 : : * Unless an RCU grace period has passed, the count of all pages coming out
133 : : * of the allocator must be considered unstable. page_count may return higher
134 : : * than expected, and put_page must be able to do the right thing when the
135 : : * page has been finished with, no matter what it is subsequently allocated
136 : : * for (because put_page is what is used here to drop an invalid speculative
137 : : * reference).
138 : : *
139 : : * This is the interesting part of the lockless pagecache (and lockless
140 : : * get_user_pages) locking protocol, where the lookup-side (eg. find_get_page)
141 : : * has the following pattern:
142 : : * 1. find page in radix tree
143 : : * 2. conditionally increment refcount
144 : : * 3. check the page is still in pagecache (if no, goto 1)
145 : : *
146 : : * Remove-side that cares about stability of _refcount (eg. reclaim) has the
147 : : * following (with the i_pages lock held):
148 : : * A. atomically check refcount is correct and set it to 0 (atomic_cmpxchg)
149 : : * B. remove page from pagecache
150 : : * C. free the page
151 : : *
152 : : * There are 2 critical interleavings that matter:
153 : : * - 2 runs before A: in this case, A sees elevated refcount and bails out
154 : : * - A runs before 2: in this case, 2 sees zero refcount and retries;
155 : : * subsequently, B will complete and 1 will find no page, causing the
156 : : * lookup to return NULL.
157 : : *
158 : : * It is possible that between 1 and 2, the page is removed then the exact same
159 : : * page is inserted into the same position in pagecache. That's OK: the
160 : : * old find_get_page using a lock could equally have run before or after
161 : : * such a re-insertion, depending on order that locks are granted.
162 : : *
163 : : * Lookups racing against pagecache insertion isn't a big problem: either 1
164 : : * will find the page or it will not. Likewise, the old find_get_page could run
165 : : * either before the insertion or afterwards, depending on timing.
166 : : */
167 : 6418649 : static inline int __page_cache_add_speculative(struct page *page, int count)
168 : : {
169 : : #ifdef CONFIG_TINY_RCU
170 : : # ifdef CONFIG_PREEMPT_COUNT
171 : : VM_BUG_ON(!in_atomic() && !irqs_disabled());
172 : : # endif
173 : : /*
174 : : * Preempt must be disabled here - we rely on rcu_read_lock doing
175 : : * this for us.
176 : : *
177 : : * Pagecache won't be truncated from interrupt context, so if we have
178 : : * found a page in the radix tree here, we have pinned its refcount by
179 : : * disabling preempt, and hence no need for the "speculative get" that
180 : : * SMP requires.
181 : : */
182 : : VM_BUG_ON_PAGE(page_count(page) == 0, page);
183 : : page_ref_add(page, count);
184 : :
185 : : #else
186 [ - + - + : 6418649 : if (unlikely(!page_ref_add_unless(page, count, 0))) {
- - - + -
+ - + ]
187 : : /*
188 : : * Either the page has been freed, or will be freed.
189 : : * In either case, retry here and the caller should
190 : : * do the right thing (see comments above).
191 : : */
192 : 0 : return 0;
193 : : }
194 : : #endif
195 : : VM_BUG_ON_PAGE(PageTail(page), page);
196 : :
197 : : return 1;
198 : : }
199 : :
200 : 6418648 : static inline int page_cache_get_speculative(struct page *page)
201 : : {
202 : 6418648 : return __page_cache_add_speculative(page, 1);
203 : : }
204 : :
205 : 1 : static inline int page_cache_add_speculative(struct page *page, int count)
206 : : {
207 : 1 : return __page_cache_add_speculative(page, count);
208 : : }
209 : :
210 : : #ifdef CONFIG_NUMA
211 : : extern struct page *__page_cache_alloc(gfp_t gfp);
212 : : #else
213 : : static inline struct page *__page_cache_alloc(gfp_t gfp)
214 : : {
215 : : return alloc_pages(gfp, 0);
216 : : }
217 : : #endif
218 : :
219 : 22 : static inline struct page *page_cache_alloc(struct address_space *x)
220 : : {
221 : 22 : return __page_cache_alloc(mapping_gfp_mask(x));
222 : : }
223 : :
224 : 122491 : static inline gfp_t readahead_gfp_mask(struct address_space *x)
225 : : {
226 [ + + ]: 122491 : return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
227 : : }
228 : :
229 : : typedef int filler_t(void *, struct page *);
230 : :
231 : : pgoff_t page_cache_next_miss(struct address_space *mapping,
232 : : pgoff_t index, unsigned long max_scan);
233 : : pgoff_t page_cache_prev_miss(struct address_space *mapping,
234 : : pgoff_t index, unsigned long max_scan);
235 : :
236 : : #define FGP_ACCESSED 0x00000001
237 : : #define FGP_LOCK 0x00000002
238 : : #define FGP_CREAT 0x00000004
239 : : #define FGP_WRITE 0x00000008
240 : : #define FGP_NOFS 0x00000010
241 : : #define FGP_NOWAIT 0x00000020
242 : : #define FGP_FOR_MMAP 0x00000040
243 : :
244 : : struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
245 : : int fgp_flags, gfp_t cache_gfp_mask);
246 : :
247 : : /**
248 : : * find_get_page - find and get a page reference
249 : : * @mapping: the address_space to search
250 : : * @offset: the page index
251 : : *
252 : : * Looks up the page cache slot at @mapping & @offset. If there is a
253 : : * page cache page, it is returned with an increased refcount.
254 : : *
255 : : * Otherwise, %NULL is returned.
256 : : */
257 : 192795 : static inline struct page *find_get_page(struct address_space *mapping,
258 : : pgoff_t offset)
259 : : {
260 : 192795 : return pagecache_get_page(mapping, offset, 0, 0);
261 : : }
262 : :
263 : 42604 : static inline struct page *find_get_page_flags(struct address_space *mapping,
264 : : pgoff_t offset, int fgp_flags)
265 : : {
266 : 42604 : return pagecache_get_page(mapping, offset, fgp_flags, 0);
267 : : }
268 : :
269 : : /**
270 : : * find_lock_page - locate, pin and lock a pagecache page
271 : : * @mapping: the address_space to search
272 : : * @offset: the page index
273 : : *
274 : : * Looks up the page cache slot at @mapping & @offset. If there is a
275 : : * page cache page, it is returned locked and with an increased
276 : : * refcount.
277 : : *
278 : : * Otherwise, %NULL is returned.
279 : : *
280 : : * find_lock_page() may sleep.
281 : : */
282 : 0 : static inline struct page *find_lock_page(struct address_space *mapping,
283 : : pgoff_t offset)
284 : : {
285 : 0 : return pagecache_get_page(mapping, offset, FGP_LOCK, 0);
286 : : }
287 : :
288 : : /**
289 : : * find_or_create_page - locate or add a pagecache page
290 : : * @mapping: the page's address_space
291 : : * @index: the page's index into the mapping
292 : : * @gfp_mask: page allocation mode
293 : : *
294 : : * Looks up the page cache slot at @mapping & @offset. If there is a
295 : : * page cache page, it is returned locked and with an increased
296 : : * refcount.
297 : : *
298 : : * If the page is not present, a new page is allocated using @gfp_mask
299 : : * and added to the page cache and the VM's LRU list. The page is
300 : : * returned locked and with an increased refcount.
301 : : *
302 : : * On memory exhaustion, %NULL is returned.
303 : : *
304 : : * find_or_create_page() may sleep, even if @gfp_flags specifies an
305 : : * atomic allocation!
306 : : */
307 : 10067 : static inline struct page *find_or_create_page(struct address_space *mapping,
308 : : pgoff_t offset, gfp_t gfp_mask)
309 : : {
310 : 10067 : return pagecache_get_page(mapping, offset,
311 : : FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
312 : : gfp_mask);
313 : : }
314 : :
315 : : /**
316 : : * grab_cache_page_nowait - returns locked page at given index in given cache
317 : : * @mapping: target address_space
318 : : * @index: the page index
319 : : *
320 : : * Same as grab_cache_page(), but do not wait if the page is unavailable.
321 : : * This is intended for speculative data generators, where the data can
322 : : * be regenerated if the page couldn't be grabbed. This routine should
323 : : * be safe to call while holding the lock for another page.
324 : : *
325 : : * Clear __GFP_FS when allocating the page to avoid recursion into the fs
326 : : * and deadlock against the caller's locked page.
327 : : */
328 : 0 : static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
329 : : pgoff_t index)
330 : : {
331 : 0 : return pagecache_get_page(mapping, index,
332 : : FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
333 : : mapping_gfp_mask(mapping));
334 : : }
335 : :
336 : 6418648 : static inline struct page *find_subpage(struct page *page, pgoff_t offset)
337 : : {
338 [ + - ]: 6418648 : if (PageHuge(page))
339 : : return page;
340 : :
341 : 6418648 : VM_BUG_ON_PAGE(PageTail(page), page);
342 : :
343 : 12837290 : return page + (offset & (compound_nr(page) - 1));
344 : : }
345 : :
346 : : struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
347 : : struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
348 : : unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
349 : : unsigned int nr_entries, struct page **entries,
350 : : pgoff_t *indices);
351 : : unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
352 : : pgoff_t end, unsigned int nr_pages,
353 : : struct page **pages);
354 : : static inline unsigned find_get_pages(struct address_space *mapping,
355 : : pgoff_t *start, unsigned int nr_pages,
356 : : struct page **pages)
357 : : {
358 : : return find_get_pages_range(mapping, start, (pgoff_t)-1, nr_pages,
359 : : pages);
360 : : }
361 : : unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
362 : : unsigned int nr_pages, struct page **pages);
363 : : unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
364 : : pgoff_t end, xa_mark_t tag, unsigned int nr_pages,
365 : : struct page **pages);
366 : : static inline unsigned find_get_pages_tag(struct address_space *mapping,
367 : : pgoff_t *index, xa_mark_t tag, unsigned int nr_pages,
368 : : struct page **pages)
369 : : {
370 : : return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
371 : : nr_pages, pages);
372 : : }
373 : :
374 : : struct page *grab_cache_page_write_begin(struct address_space *mapping,
375 : : pgoff_t index, unsigned flags);
376 : :
377 : : /*
378 : : * Returns locked page at given index in given cache, creating it if needed.
379 : : */
380 : 0 : static inline struct page *grab_cache_page(struct address_space *mapping,
381 : : pgoff_t index)
382 : : {
383 : 0 : return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
384 : : }
385 : :
386 : : extern struct page * read_cache_page(struct address_space *mapping,
387 : : pgoff_t index, filler_t *filler, void *data);
388 : : extern struct page * read_cache_page_gfp(struct address_space *mapping,
389 : : pgoff_t index, gfp_t gfp_mask);
390 : : extern int read_cache_pages(struct address_space *mapping,
391 : : struct list_head *pages, filler_t *filler, void *data);
392 : :
393 : 44 : static inline struct page *read_mapping_page(struct address_space *mapping,
394 : : pgoff_t index, void *data)
395 : : {
396 : 44 : return read_cache_page(mapping, index, NULL, data);
397 : : }
398 : :
399 : : /*
400 : : * Get index of the page with in radix-tree
401 : : * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
402 : : */
403 : 5852 : static inline pgoff_t page_to_index(struct page *page)
404 : : {
405 : 5852 : pgoff_t pgoff;
406 : :
407 [ - - - - : 5852 : if (likely(!PageTransTail(page)))
- + - - ]
408 [ - - - - : 5852 : return page->index;
- + - - ]
409 : :
410 : : /*
411 : : * We don't initialize ->index for tail pages: calculate based on
412 : : * head page
413 : : */
414 : : pgoff = compound_head(page)->index;
415 : : pgoff += page - compound_head(page);
416 : : return pgoff;
417 : : }
418 : :
419 : : /*
420 : : * Get the offset in PAGE_SIZE.
421 : : * (TODO: hugepage should have ->index in PAGE_SIZE)
422 : : */
423 : 0 : static inline pgoff_t page_to_pgoff(struct page *page)
424 : : {
425 [ # # ]: 0 : if (unlikely(PageHeadHuge(page)))
426 : 0 : return page->index << compound_order(page);
427 : :
428 : 0 : return page_to_index(page);
429 : : }
430 : :
431 : : /*
432 : : * Return byte-offset into filesystem object for page.
433 : : */
434 : 0 : static inline loff_t page_offset(struct page *page)
435 : : {
436 [ # # ]: 0 : return ((loff_t)page->index) << PAGE_SHIFT;
437 : : }
438 : :
439 : 0 : static inline loff_t page_file_offset(struct page *page)
440 : : {
441 [ # # ]: 0 : return ((loff_t)page_index(page)) << PAGE_SHIFT;
442 : : }
443 : :
444 : : extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
445 : : unsigned long address);
446 : :
447 : 1571682 : static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
448 : : unsigned long address)
449 : : {
450 : 1571682 : pgoff_t pgoff;
451 [ - + ]: 1571682 : if (unlikely(is_vm_hugetlb_page(vma)))
452 : 0 : return linear_hugepage_index(vma, address);
453 : 1571682 : pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
454 : 1571682 : pgoff += vma->vm_pgoff;
455 : 1571682 : return pgoff;
456 : : }
457 : :
458 : : extern void __lock_page(struct page *page);
459 : : extern int __lock_page_killable(struct page *page);
460 : : extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
461 : : unsigned int flags);
462 : : extern void unlock_page(struct page *page);
463 : :
464 : : /*
465 : : * Return true if the page was successfully locked
466 : : */
467 : 6476184 : static inline int trylock_page(struct page *page)
468 : : {
469 [ - + - + : 6464021 : page = compound_head(page);
- - - - #
# ]
470 [ - + + + : 6476184 : return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
- - - - #
# ]
471 : : }
472 : :
473 : : /*
474 : : * lock_page may only be called if we have the page's inode pinned.
475 : : */
476 : 20866 : static inline void lock_page(struct page *page)
477 : : {
478 : 20866 : might_sleep();
479 [ - + - + ]: 41732 : if (!trylock_page(page))
480 : 0 : __lock_page(page);
481 : 20866 : }
482 : :
483 : : /*
484 : : * lock_page_killable is like lock_page but can be interrupted by fatal
485 : : * signals. It returns 0 if it locked the page and -EINTR if it was
486 : : * killed while waiting.
487 : : */
488 : 33 : static inline int lock_page_killable(struct page *page)
489 : : {
490 : 33 : might_sleep();
491 [ - + - + ]: 66 : if (!trylock_page(page))
492 : 0 : return __lock_page_killable(page);
493 : : return 0;
494 : : }
495 : :
496 : : /*
497 : : * lock_page_or_retry - Lock the page, unless this would block and the
498 : : * caller indicated that it can handle a retry.
499 : : *
500 : : * Return value and mmap_sem implications depend on flags; see
501 : : * __lock_page_or_retry().
502 : : */
503 : 0 : static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm,
504 : : unsigned int flags)
505 : : {
506 : 0 : might_sleep();
507 [ # # # # : 0 : return trylock_page(page) || __lock_page_or_retry(page, mm, flags);
# # ]
508 : : }
509 : :
510 : : /*
511 : : * This is exported only for wait_on_page_locked/wait_on_page_writeback, etc.,
512 : : * and should not be used directly.
513 : : */
514 : : extern void wait_on_page_bit(struct page *page, int bit_nr);
515 : : extern int wait_on_page_bit_killable(struct page *page, int bit_nr);
516 : :
517 : : /*
518 : : * Wait for a page to be unlocked.
519 : : *
520 : : * This must be called with the caller "holding" the page,
521 : : * ie with increased "page->count" so that the page won't
522 : : * go away during the wait..
523 : : */
524 : 22 : static inline void wait_on_page_locked(struct page *page)
525 : : {
526 [ - + + - ]: 44 : if (PageLocked(page))
527 [ - + ]: 22 : wait_on_page_bit(compound_head(page), PG_locked);
528 : 22 : }
529 : :
530 : 4248 : static inline int wait_on_page_locked_killable(struct page *page)
531 : : {
532 [ - + + + ]: 8496 : if (!PageLocked(page))
533 : : return 0;
534 [ - + ]: 8418 : return wait_on_page_bit_killable(compound_head(page), PG_locked);
535 : : }
536 : :
537 : : extern void put_and_wait_on_page_locked(struct page *page);
538 : :
539 : : void wait_on_page_writeback(struct page *page);
540 : : extern void end_page_writeback(struct page *page);
541 : : void wait_for_stable_page(struct page *page);
542 : :
543 : : void page_endio(struct page *page, bool is_write, int err);
544 : :
545 : : /*
546 : : * Add an arbitrary waiter to a page's wait queue
547 : : */
548 : : extern void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter);
549 : :
550 : : /*
551 : : * Fault everything in given userspace address range in.
552 : : */
553 : 3970 : static inline int fault_in_pages_writeable(char __user *uaddr, int size)
554 : : {
555 : 3970 : char __user *end = uaddr + size - 1;
556 : :
557 [ + - ]: 3970 : if (unlikely(size == 0))
558 : : return 0;
559 : :
560 [ + - ]: 3970 : if (unlikely(uaddr > end))
561 : : return -EFAULT;
562 : : /*
563 : : * Writing zeroes into userspace here is OK, because we know that if
564 : : * the zero gets there, we'll be overwriting it.
565 : : */
566 : 3970 : do {
567 [ + - + - ]: 3970 : if (unlikely(__put_user(0, uaddr) != 0))
568 : : return -EFAULT;
569 : 3970 : uaddr += PAGE_SIZE;
570 [ - + ]: 3970 : } while (uaddr <= end);
571 : :
572 : : /* Check whether the range spilled into the next page. */
573 : 3970 : if (((unsigned long)uaddr & PAGE_MASK) ==
574 [ + + ]: 3970 : ((unsigned long)end & PAGE_MASK))
575 [ + - ]: 2730 : return __put_user(0, end);
576 : :
577 : : return 0;
578 : : }
579 : :
580 : 37346 : static inline int fault_in_pages_readable(const char __user *uaddr, int size)
581 : : {
582 : 37346 : volatile char c;
583 : 37346 : const char __user *end = uaddr + size - 1;
584 : :
585 [ + - ]: 37346 : if (unlikely(size == 0))
586 : : return 0;
587 : :
588 [ + - ]: 37346 : if (unlikely(uaddr > end))
589 : : return -EFAULT;
590 : :
591 : 37346 : do {
592 [ + - ]: 37346 : if (unlikely(__get_user(c, uaddr) != 0))
593 : : return -EFAULT;
594 : 37346 : uaddr += PAGE_SIZE;
595 [ - + ]: 37346 : } while (uaddr <= end);
596 : :
597 : : /* Check whether the range spilled into the next page. */
598 : 37346 : if (((unsigned long)uaddr & PAGE_MASK) ==
599 [ + + ]: 37346 : ((unsigned long)end & PAGE_MASK)) {
600 : 462 : return __get_user(c, end);
601 : : }
602 : :
603 : 36884 : (void)c;
604 : 36884 : return 0;
605 : : }
606 : :
607 : : int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
608 : : pgoff_t index, gfp_t gfp_mask);
609 : : int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
610 : : pgoff_t index, gfp_t gfp_mask);
611 : : extern void delete_from_page_cache(struct page *page);
612 : : extern void __delete_from_page_cache(struct page *page, void *shadow);
613 : : int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
614 : : void delete_from_page_cache_batch(struct address_space *mapping,
615 : : struct pagevec *pvec);
616 : :
617 : : /*
618 : : * Like add_to_page_cache_locked, but used to add newly allocated pages:
619 : : * the page is new, so we can just run __SetPageLocked() against it.
620 : : */
621 : 0 : static inline int add_to_page_cache(struct page *page,
622 : : struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask)
623 : : {
624 : 0 : int error;
625 : :
626 [ # # ]: 0 : __SetPageLocked(page);
627 : 0 : error = add_to_page_cache_locked(page, mapping, offset, gfp_mask);
628 [ # # ]: 0 : if (unlikely(error))
629 [ # # ]: 0 : __ClearPageLocked(page);
630 : 0 : return error;
631 : : }
632 : :
633 : : static inline unsigned long dir_pages(struct inode *inode)
634 : : {
635 : : return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
636 : : PAGE_SHIFT;
637 : : }
638 : :
639 : : /**
640 : : * page_mkwrite_check_truncate - check if page was truncated
641 : : * @page: the page to check
642 : : * @inode: the inode to check the page against
643 : : *
644 : : * Returns the number of bytes in the page up to EOF,
645 : : * or -EFAULT if the page was truncated.
646 : : */
647 : 0 : static inline int page_mkwrite_check_truncate(struct page *page,
648 : : struct inode *inode)
649 : : {
650 [ # # ]: 0 : loff_t size = i_size_read(inode);
651 : 0 : pgoff_t index = size >> PAGE_SHIFT;
652 : 0 : int offset = offset_in_page(size);
653 : :
654 [ # # ]: 0 : if (page->mapping != inode->i_mapping)
655 : : return -EFAULT;
656 : :
657 : : /* page is wholly inside EOF */
658 [ # # ]: 0 : if (page->index < index)
659 : : return PAGE_SIZE;
660 : : /* page is wholly past EOF */
661 [ # # # # ]: 0 : if (page->index > index || !offset)
662 : 0 : return -EFAULT;
663 : : /* page is partially inside EOF */
664 : : return offset;
665 : : }
666 : :
667 : : #endif /* _LINUX_PAGEMAP_H */
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