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 folio_batch;
20
21 unsigned long invalidate_mapping_pages(struct address_space *mapping,
22 pgoff_t start, pgoff_t end);
23
invalidate_remote_inode(struct inode * inode)24 static inline void invalidate_remote_inode(struct inode *inode)
25 {
26 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
27 S_ISLNK(inode->i_mode))
28 invalidate_mapping_pages(inode->i_mapping, 0, -1);
29 }
30 int invalidate_inode_pages2(struct address_space *mapping);
31 int invalidate_inode_pages2_range(struct address_space *mapping,
32 pgoff_t start, pgoff_t end);
33 int kiocb_invalidate_pages(struct kiocb *iocb, size_t count);
34 void kiocb_invalidate_post_direct_write(struct kiocb *iocb, size_t count);
35
36 int write_inode_now(struct inode *, int sync);
37 int filemap_fdatawrite(struct address_space *);
38 int filemap_flush(struct address_space *);
39 int filemap_fdatawait_keep_errors(struct address_space *mapping);
40 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
41 int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
42 loff_t start_byte, loff_t end_byte);
43
filemap_fdatawait(struct address_space * mapping)44 static inline int filemap_fdatawait(struct address_space *mapping)
45 {
46 return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
47 }
48
49 bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend);
50 int filemap_write_and_wait_range(struct address_space *mapping,
51 loff_t lstart, loff_t lend);
52 int __filemap_fdatawrite_range(struct address_space *mapping,
53 loff_t start, loff_t end, int sync_mode);
54 int filemap_fdatawrite_range(struct address_space *mapping,
55 loff_t start, loff_t end);
56 int filemap_check_errors(struct address_space *mapping);
57 void __filemap_set_wb_err(struct address_space *mapping, int err);
58 int filemap_fdatawrite_wbc(struct address_space *mapping,
59 struct writeback_control *wbc);
60 int kiocb_write_and_wait(struct kiocb *iocb, size_t count);
61
filemap_write_and_wait(struct address_space * mapping)62 static inline int filemap_write_and_wait(struct address_space *mapping)
63 {
64 return filemap_write_and_wait_range(mapping, 0, LLONG_MAX);
65 }
66
67 /**
68 * filemap_set_wb_err - set a writeback error on an address_space
69 * @mapping: mapping in which to set writeback error
70 * @err: error to be set in mapping
71 *
72 * When writeback fails in some way, we must record that error so that
73 * userspace can be informed when fsync and the like are called. We endeavor
74 * to report errors on any file that was open at the time of the error. Some
75 * internal callers also need to know when writeback errors have occurred.
76 *
77 * When a writeback error occurs, most filesystems will want to call
78 * filemap_set_wb_err to record the error in the mapping so that it will be
79 * automatically reported whenever fsync is called on the file.
80 */
filemap_set_wb_err(struct address_space * mapping,int err)81 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
82 {
83 /* Fastpath for common case of no error */
84 if (unlikely(err))
85 __filemap_set_wb_err(mapping, err);
86 }
87
88 /**
89 * filemap_check_wb_err - has an error occurred since the mark was sampled?
90 * @mapping: mapping to check for writeback errors
91 * @since: previously-sampled errseq_t
92 *
93 * Grab the errseq_t value from the mapping, and see if it has changed "since"
94 * the given value was sampled.
95 *
96 * If it has then report the latest error set, otherwise return 0.
97 */
filemap_check_wb_err(struct address_space * mapping,errseq_t since)98 static inline int filemap_check_wb_err(struct address_space *mapping,
99 errseq_t since)
100 {
101 return errseq_check(&mapping->wb_err, since);
102 }
103
104 /**
105 * filemap_sample_wb_err - sample the current errseq_t to test for later errors
106 * @mapping: mapping to be sampled
107 *
108 * Writeback errors are always reported relative to a particular sample point
109 * in the past. This function provides those sample points.
110 */
filemap_sample_wb_err(struct address_space * mapping)111 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
112 {
113 return errseq_sample(&mapping->wb_err);
114 }
115
116 /**
117 * file_sample_sb_err - sample the current errseq_t to test for later errors
118 * @file: file pointer to be sampled
119 *
120 * Grab the most current superblock-level errseq_t value for the given
121 * struct file.
122 */
file_sample_sb_err(struct file * file)123 static inline errseq_t file_sample_sb_err(struct file *file)
124 {
125 return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err);
126 }
127
128 /*
129 * Flush file data before changing attributes. Caller must hold any locks
130 * required to prevent further writes to this file until we're done setting
131 * flags.
132 */
inode_drain_writes(struct inode * inode)133 static inline int inode_drain_writes(struct inode *inode)
134 {
135 inode_dio_wait(inode);
136 return filemap_write_and_wait(inode->i_mapping);
137 }
138
mapping_empty(struct address_space * mapping)139 static inline bool mapping_empty(struct address_space *mapping)
140 {
141 return xa_empty(&mapping->i_pages);
142 }
143
144 /*
145 * mapping_shrinkable - test if page cache state allows inode reclaim
146 * @mapping: the page cache mapping
147 *
148 * This checks the mapping's cache state for the pupose of inode
149 * reclaim and LRU management.
150 *
151 * The caller is expected to hold the i_lock, but is not required to
152 * hold the i_pages lock, which usually protects cache state. That's
153 * because the i_lock and the list_lru lock that protect the inode and
154 * its LRU state don't nest inside the irq-safe i_pages lock.
155 *
156 * Cache deletions are performed under the i_lock, which ensures that
157 * when an inode goes empty, it will reliably get queued on the LRU.
158 *
159 * Cache additions do not acquire the i_lock and may race with this
160 * check, in which case we'll report the inode as shrinkable when it
161 * has cache pages. This is okay: the shrinker also checks the
162 * refcount and the referenced bit, which will be elevated or set in
163 * the process of adding new cache pages to an inode.
164 */
mapping_shrinkable(struct address_space * mapping)165 static inline bool mapping_shrinkable(struct address_space *mapping)
166 {
167 void *head;
168
169 /*
170 * On highmem systems, there could be lowmem pressure from the
171 * inodes before there is highmem pressure from the page
172 * cache. Make inodes shrinkable regardless of cache state.
173 */
174 if (IS_ENABLED(CONFIG_HIGHMEM))
175 return true;
176
177 /* Cache completely empty? Shrink away. */
178 head = rcu_access_pointer(mapping->i_pages.xa_head);
179 if (!head)
180 return true;
181
182 /*
183 * The xarray stores single offset-0 entries directly in the
184 * head pointer, which allows non-resident page cache entries
185 * to escape the shadow shrinker's list of xarray nodes. The
186 * inode shrinker needs to pick them up under memory pressure.
187 */
188 if (!xa_is_node(head) && xa_is_value(head))
189 return true;
190
191 return false;
192 }
193
194 /*
195 * Bits in mapping->flags.
196 */
197 enum mapping_flags {
198 AS_EIO = 0, /* IO error on async write */
199 AS_ENOSPC = 1, /* ENOSPC on async write */
200 AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */
201 AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */
202 AS_EXITING = 4, /* final truncate in progress */
203 /* writeback related tags are not used */
204 AS_NO_WRITEBACK_TAGS = 5,
205 AS_LARGE_FOLIO_SUPPORT = 6,
206 AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */
207 AS_STABLE_WRITES, /* must wait for writeback before modifying
208 folio contents */
209 };
210
211 /**
212 * mapping_set_error - record a writeback error in the address_space
213 * @mapping: the mapping in which an error should be set
214 * @error: the error to set in the mapping
215 *
216 * When writeback fails in some way, we must record that error so that
217 * userspace can be informed when fsync and the like are called. We endeavor
218 * to report errors on any file that was open at the time of the error. Some
219 * internal callers also need to know when writeback errors have occurred.
220 *
221 * When a writeback error occurs, most filesystems will want to call
222 * mapping_set_error to record the error in the mapping so that it can be
223 * reported when the application calls fsync(2).
224 */
mapping_set_error(struct address_space * mapping,int error)225 static inline void mapping_set_error(struct address_space *mapping, int error)
226 {
227 if (likely(!error))
228 return;
229
230 /* Record in wb_err for checkers using errseq_t based tracking */
231 __filemap_set_wb_err(mapping, error);
232
233 /* Record it in superblock */
234 if (mapping->host)
235 errseq_set(&mapping->host->i_sb->s_wb_err, error);
236
237 /* Record it in flags for now, for legacy callers */
238 if (error == -ENOSPC)
239 set_bit(AS_ENOSPC, &mapping->flags);
240 else
241 set_bit(AS_EIO, &mapping->flags);
242 }
243
mapping_set_unevictable(struct address_space * mapping)244 static inline void mapping_set_unevictable(struct address_space *mapping)
245 {
246 set_bit(AS_UNEVICTABLE, &mapping->flags);
247 }
248
mapping_clear_unevictable(struct address_space * mapping)249 static inline void mapping_clear_unevictable(struct address_space *mapping)
250 {
251 clear_bit(AS_UNEVICTABLE, &mapping->flags);
252 }
253
mapping_unevictable(struct address_space * mapping)254 static inline bool mapping_unevictable(struct address_space *mapping)
255 {
256 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags);
257 }
258
mapping_set_exiting(struct address_space * mapping)259 static inline void mapping_set_exiting(struct address_space *mapping)
260 {
261 set_bit(AS_EXITING, &mapping->flags);
262 }
263
mapping_exiting(struct address_space * mapping)264 static inline int mapping_exiting(struct address_space *mapping)
265 {
266 return test_bit(AS_EXITING, &mapping->flags);
267 }
268
mapping_set_no_writeback_tags(struct address_space * mapping)269 static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
270 {
271 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
272 }
273
mapping_use_writeback_tags(struct address_space * mapping)274 static inline int mapping_use_writeback_tags(struct address_space *mapping)
275 {
276 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
277 }
278
mapping_release_always(const struct address_space * mapping)279 static inline bool mapping_release_always(const struct address_space *mapping)
280 {
281 return test_bit(AS_RELEASE_ALWAYS, &mapping->flags);
282 }
283
mapping_set_release_always(struct address_space * mapping)284 static inline void mapping_set_release_always(struct address_space *mapping)
285 {
286 set_bit(AS_RELEASE_ALWAYS, &mapping->flags);
287 }
288
mapping_clear_release_always(struct address_space * mapping)289 static inline void mapping_clear_release_always(struct address_space *mapping)
290 {
291 clear_bit(AS_RELEASE_ALWAYS, &mapping->flags);
292 }
293
mapping_stable_writes(const struct address_space * mapping)294 static inline bool mapping_stable_writes(const struct address_space *mapping)
295 {
296 return test_bit(AS_STABLE_WRITES, &mapping->flags);
297 }
298
mapping_set_stable_writes(struct address_space * mapping)299 static inline void mapping_set_stable_writes(struct address_space *mapping)
300 {
301 set_bit(AS_STABLE_WRITES, &mapping->flags);
302 }
303
mapping_clear_stable_writes(struct address_space * mapping)304 static inline void mapping_clear_stable_writes(struct address_space *mapping)
305 {
306 clear_bit(AS_STABLE_WRITES, &mapping->flags);
307 }
308
mapping_gfp_mask(struct address_space * mapping)309 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
310 {
311 return mapping->gfp_mask;
312 }
313
314 /* Restricts the given gfp_mask to what the mapping allows. */
mapping_gfp_constraint(struct address_space * mapping,gfp_t gfp_mask)315 static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
316 gfp_t gfp_mask)
317 {
318 return mapping_gfp_mask(mapping) & gfp_mask;
319 }
320
321 /*
322 * This is non-atomic. Only to be used before the mapping is activated.
323 * Probably needs a barrier...
324 */
mapping_set_gfp_mask(struct address_space * m,gfp_t mask)325 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
326 {
327 m->gfp_mask = mask;
328 }
329
330 /*
331 * There are some parts of the kernel which assume that PMD entries
332 * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then,
333 * limit the maximum allocation order to PMD size. I'm not aware of any
334 * assumptions about maximum order if THP are disabled, but 8 seems like
335 * a good order (that's 1MB if you're using 4kB pages)
336 */
337 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
338 #define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER
339 #else
340 #define MAX_PAGECACHE_ORDER 8
341 #endif
342
343 /**
344 * mapping_set_large_folios() - Indicate the file supports large folios.
345 * @mapping: The file.
346 *
347 * The filesystem should call this function in its inode constructor to
348 * indicate that the VFS can use large folios to cache the contents of
349 * the file.
350 *
351 * Context: This should not be called while the inode is active as it
352 * is non-atomic.
353 */
mapping_set_large_folios(struct address_space * mapping)354 static inline void mapping_set_large_folios(struct address_space *mapping)
355 {
356 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
357 }
358
359 /*
360 * Large folio support currently depends on THP. These dependencies are
361 * being worked on but are not yet fixed.
362 */
mapping_large_folio_support(struct address_space * mapping)363 static inline bool mapping_large_folio_support(struct address_space *mapping)
364 {
365 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
366 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
367 }
368
369 /* Return the maximum folio size for this pagecache mapping, in bytes. */
mapping_max_folio_size(struct address_space * mapping)370 static inline size_t mapping_max_folio_size(struct address_space *mapping)
371 {
372 if (mapping_large_folio_support(mapping))
373 return PAGE_SIZE << MAX_PAGECACHE_ORDER;
374 return PAGE_SIZE;
375 }
376
filemap_nr_thps(struct address_space * mapping)377 static inline int filemap_nr_thps(struct address_space *mapping)
378 {
379 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
380 return atomic_read(&mapping->nr_thps);
381 #else
382 return 0;
383 #endif
384 }
385
filemap_nr_thps_inc(struct address_space * mapping)386 static inline void filemap_nr_thps_inc(struct address_space *mapping)
387 {
388 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
389 if (!mapping_large_folio_support(mapping))
390 atomic_inc(&mapping->nr_thps);
391 #else
392 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
393 #endif
394 }
395
filemap_nr_thps_dec(struct address_space * mapping)396 static inline void filemap_nr_thps_dec(struct address_space *mapping)
397 {
398 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
399 if (!mapping_large_folio_support(mapping))
400 atomic_dec(&mapping->nr_thps);
401 #else
402 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
403 #endif
404 }
405
406 struct address_space *page_mapping(struct page *);
407 struct address_space *folio_mapping(struct folio *);
408 struct address_space *swapcache_mapping(struct folio *);
409
410 /**
411 * folio_file_mapping - Find the mapping this folio belongs to.
412 * @folio: The folio.
413 *
414 * For folios which are in the page cache, return the mapping that this
415 * page belongs to. Folios in the swap cache return the mapping of the
416 * swap file or swap device where the data is stored. This is different
417 * from the mapping returned by folio_mapping(). The only reason to
418 * use it is if, like NFS, you return 0 from ->activate_swapfile.
419 *
420 * Do not call this for folios which aren't in the page cache or swap cache.
421 */
folio_file_mapping(struct folio * folio)422 static inline struct address_space *folio_file_mapping(struct folio *folio)
423 {
424 if (unlikely(folio_test_swapcache(folio)))
425 return swapcache_mapping(folio);
426
427 return folio->mapping;
428 }
429
430 /**
431 * folio_flush_mapping - Find the file mapping this folio belongs to.
432 * @folio: The folio.
433 *
434 * For folios which are in the page cache, return the mapping that this
435 * page belongs to. Anonymous folios return NULL, even if they're in
436 * the swap cache. Other kinds of folio also return NULL.
437 *
438 * This is ONLY used by architecture cache flushing code. If you aren't
439 * writing cache flushing code, you want either folio_mapping() or
440 * folio_file_mapping().
441 */
folio_flush_mapping(struct folio * folio)442 static inline struct address_space *folio_flush_mapping(struct folio *folio)
443 {
444 if (unlikely(folio_test_swapcache(folio)))
445 return NULL;
446
447 return folio_mapping(folio);
448 }
449
page_file_mapping(struct page * page)450 static inline struct address_space *page_file_mapping(struct page *page)
451 {
452 return folio_file_mapping(page_folio(page));
453 }
454
455 /**
456 * folio_inode - Get the host inode for this folio.
457 * @folio: The folio.
458 *
459 * For folios which are in the page cache, return the inode that this folio
460 * belongs to.
461 *
462 * Do not call this for folios which aren't in the page cache.
463 */
folio_inode(struct folio * folio)464 static inline struct inode *folio_inode(struct folio *folio)
465 {
466 return folio->mapping->host;
467 }
468
469 /**
470 * folio_attach_private - Attach private data to a folio.
471 * @folio: Folio to attach data to.
472 * @data: Data to attach to folio.
473 *
474 * Attaching private data to a folio increments the page's reference count.
475 * The data must be detached before the folio will be freed.
476 */
folio_attach_private(struct folio * folio,void * data)477 static inline void folio_attach_private(struct folio *folio, void *data)
478 {
479 folio_get(folio);
480 folio->private = data;
481 folio_set_private(folio);
482 }
483
484 /**
485 * folio_change_private - Change private data on a folio.
486 * @folio: Folio to change the data on.
487 * @data: Data to set on the folio.
488 *
489 * Change the private data attached to a folio and return the old
490 * data. The page must previously have had data attached and the data
491 * must be detached before the folio will be freed.
492 *
493 * Return: Data that was previously attached to the folio.
494 */
folio_change_private(struct folio * folio,void * data)495 static inline void *folio_change_private(struct folio *folio, void *data)
496 {
497 void *old = folio_get_private(folio);
498
499 folio->private = data;
500 return old;
501 }
502
503 /**
504 * folio_detach_private - Detach private data from a folio.
505 * @folio: Folio to detach data from.
506 *
507 * Removes the data that was previously attached to the folio and decrements
508 * the refcount on the page.
509 *
510 * Return: Data that was attached to the folio.
511 */
folio_detach_private(struct folio * folio)512 static inline void *folio_detach_private(struct folio *folio)
513 {
514 void *data = folio_get_private(folio);
515
516 if (!folio_test_private(folio))
517 return NULL;
518 folio_clear_private(folio);
519 folio->private = NULL;
520 folio_put(folio);
521
522 return data;
523 }
524
attach_page_private(struct page * page,void * data)525 static inline void attach_page_private(struct page *page, void *data)
526 {
527 folio_attach_private(page_folio(page), data);
528 }
529
detach_page_private(struct page * page)530 static inline void *detach_page_private(struct page *page)
531 {
532 return folio_detach_private(page_folio(page));
533 }
534
535 #ifdef CONFIG_NUMA
536 struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
537 #else
filemap_alloc_folio(gfp_t gfp,unsigned int order)538 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
539 {
540 return folio_alloc(gfp, order);
541 }
542 #endif
543
__page_cache_alloc(gfp_t gfp)544 static inline struct page *__page_cache_alloc(gfp_t gfp)
545 {
546 return &filemap_alloc_folio(gfp, 0)->page;
547 }
548
page_cache_alloc(struct address_space * x)549 static inline struct page *page_cache_alloc(struct address_space *x)
550 {
551 return __page_cache_alloc(mapping_gfp_mask(x));
552 }
553
readahead_gfp_mask(struct address_space * x)554 static inline gfp_t readahead_gfp_mask(struct address_space *x)
555 {
556 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
557 }
558
559 typedef int filler_t(struct file *, struct folio *);
560
561 pgoff_t page_cache_next_miss(struct address_space *mapping,
562 pgoff_t index, unsigned long max_scan);
563 pgoff_t page_cache_prev_miss(struct address_space *mapping,
564 pgoff_t index, unsigned long max_scan);
565
566 /**
567 * typedef fgf_t - Flags for getting folios from the page cache.
568 *
569 * Most users of the page cache will not need to use these flags;
570 * there are convenience functions such as filemap_get_folio() and
571 * filemap_lock_folio(). For users which need more control over exactly
572 * what is done with the folios, these flags to __filemap_get_folio()
573 * are available.
574 *
575 * * %FGP_ACCESSED - The folio will be marked accessed.
576 * * %FGP_LOCK - The folio is returned locked.
577 * * %FGP_CREAT - If no folio is present then a new folio is allocated,
578 * added to the page cache and the VM's LRU list. The folio is
579 * returned locked.
580 * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the
581 * folio is already in cache. If the folio was allocated, unlock it
582 * before returning so the caller can do the same dance.
583 * * %FGP_WRITE - The folio will be written to by the caller.
584 * * %FGP_NOFS - __GFP_FS will get cleared in gfp.
585 * * %FGP_NOWAIT - Don't block on the folio lock.
586 * * %FGP_STABLE - Wait for the folio to be stable (finished writeback)
587 * * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin()
588 * implementation.
589 */
590 typedef unsigned int __bitwise fgf_t;
591
592 #define FGP_ACCESSED ((__force fgf_t)0x00000001)
593 #define FGP_LOCK ((__force fgf_t)0x00000002)
594 #define FGP_CREAT ((__force fgf_t)0x00000004)
595 #define FGP_WRITE ((__force fgf_t)0x00000008)
596 #define FGP_NOFS ((__force fgf_t)0x00000010)
597 #define FGP_NOWAIT ((__force fgf_t)0x00000020)
598 #define FGP_FOR_MMAP ((__force fgf_t)0x00000040)
599 #define FGP_STABLE ((__force fgf_t)0x00000080)
600 #define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */
601
602 #define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
603
604 /**
605 * fgf_set_order - Encode a length in the fgf_t flags.
606 * @size: The suggested size of the folio to create.
607 *
608 * The caller of __filemap_get_folio() can use this to suggest a preferred
609 * size for the folio that is created. If there is already a folio at
610 * the index, it will be returned, no matter what its size. If a folio
611 * is freshly created, it may be of a different size than requested
612 * due to alignment constraints, memory pressure, or the presence of
613 * other folios at nearby indices.
614 */
fgf_set_order(size_t size)615 static inline fgf_t fgf_set_order(size_t size)
616 {
617 unsigned int shift = ilog2(size);
618
619 if (shift <= PAGE_SHIFT)
620 return 0;
621 return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
622 }
623
624 void *filemap_get_entry(struct address_space *mapping, pgoff_t index);
625 struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
626 fgf_t fgp_flags, gfp_t gfp);
627 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
628 fgf_t fgp_flags, gfp_t gfp);
629
630 /**
631 * filemap_get_folio - Find and get a folio.
632 * @mapping: The address_space to search.
633 * @index: The page index.
634 *
635 * Looks up the page cache entry at @mapping & @index. If a folio is
636 * present, it is returned with an increased refcount.
637 *
638 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
639 * this index. Will not return a shadow, swap or DAX entry.
640 */
filemap_get_folio(struct address_space * mapping,pgoff_t index)641 static inline struct folio *filemap_get_folio(struct address_space *mapping,
642 pgoff_t index)
643 {
644 return __filemap_get_folio(mapping, index, 0, 0);
645 }
646
647 /**
648 * filemap_lock_folio - Find and lock a folio.
649 * @mapping: The address_space to search.
650 * @index: The page index.
651 *
652 * Looks up the page cache entry at @mapping & @index. If a folio is
653 * present, it is returned locked with an increased refcount.
654 *
655 * Context: May sleep.
656 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
657 * this index. Will not return a shadow, swap or DAX entry.
658 */
filemap_lock_folio(struct address_space * mapping,pgoff_t index)659 static inline struct folio *filemap_lock_folio(struct address_space *mapping,
660 pgoff_t index)
661 {
662 return __filemap_get_folio(mapping, index, FGP_LOCK, 0);
663 }
664
665 /**
666 * filemap_grab_folio - grab a folio from the page cache
667 * @mapping: The address space to search
668 * @index: The page index
669 *
670 * Looks up the page cache entry at @mapping & @index. If no folio is found,
671 * a new folio is created. The folio is locked, marked as accessed, and
672 * returned.
673 *
674 * Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found
675 * and failed to create a folio.
676 */
filemap_grab_folio(struct address_space * mapping,pgoff_t index)677 static inline struct folio *filemap_grab_folio(struct address_space *mapping,
678 pgoff_t index)
679 {
680 return __filemap_get_folio(mapping, index,
681 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
682 mapping_gfp_mask(mapping));
683 }
684
685 /**
686 * find_get_page - find and get a page reference
687 * @mapping: the address_space to search
688 * @offset: the page index
689 *
690 * Looks up the page cache slot at @mapping & @offset. If there is a
691 * page cache page, it is returned with an increased refcount.
692 *
693 * Otherwise, %NULL is returned.
694 */
find_get_page(struct address_space * mapping,pgoff_t offset)695 static inline struct page *find_get_page(struct address_space *mapping,
696 pgoff_t offset)
697 {
698 return pagecache_get_page(mapping, offset, 0, 0);
699 }
700
find_get_page_flags(struct address_space * mapping,pgoff_t offset,fgf_t fgp_flags)701 static inline struct page *find_get_page_flags(struct address_space *mapping,
702 pgoff_t offset, fgf_t fgp_flags)
703 {
704 return pagecache_get_page(mapping, offset, fgp_flags, 0);
705 }
706
707 /**
708 * find_lock_page - locate, pin and lock a pagecache page
709 * @mapping: the address_space to search
710 * @index: the page index
711 *
712 * Looks up the page cache entry at @mapping & @index. If there is a
713 * page cache page, it is returned locked and with an increased
714 * refcount.
715 *
716 * Context: May sleep.
717 * Return: A struct page or %NULL if there is no page in the cache for this
718 * index.
719 */
find_lock_page(struct address_space * mapping,pgoff_t index)720 static inline struct page *find_lock_page(struct address_space *mapping,
721 pgoff_t index)
722 {
723 return pagecache_get_page(mapping, index, FGP_LOCK, 0);
724 }
725
726 /**
727 * find_or_create_page - locate or add a pagecache page
728 * @mapping: the page's address_space
729 * @index: the page's index into the mapping
730 * @gfp_mask: page allocation mode
731 *
732 * Looks up the page cache slot at @mapping & @offset. If there is a
733 * page cache page, it is returned locked and with an increased
734 * refcount.
735 *
736 * If the page is not present, a new page is allocated using @gfp_mask
737 * and added to the page cache and the VM's LRU list. The page is
738 * returned locked and with an increased refcount.
739 *
740 * On memory exhaustion, %NULL is returned.
741 *
742 * find_or_create_page() may sleep, even if @gfp_flags specifies an
743 * atomic allocation!
744 */
find_or_create_page(struct address_space * mapping,pgoff_t index,gfp_t gfp_mask)745 static inline struct page *find_or_create_page(struct address_space *mapping,
746 pgoff_t index, gfp_t gfp_mask)
747 {
748 return pagecache_get_page(mapping, index,
749 FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
750 gfp_mask);
751 }
752
753 /**
754 * grab_cache_page_nowait - returns locked page at given index in given cache
755 * @mapping: target address_space
756 * @index: the page index
757 *
758 * Same as grab_cache_page(), but do not wait if the page is unavailable.
759 * This is intended for speculative data generators, where the data can
760 * be regenerated if the page couldn't be grabbed. This routine should
761 * be safe to call while holding the lock for another page.
762 *
763 * Clear __GFP_FS when allocating the page to avoid recursion into the fs
764 * and deadlock against the caller's locked page.
765 */
grab_cache_page_nowait(struct address_space * mapping,pgoff_t index)766 static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
767 pgoff_t index)
768 {
769 return pagecache_get_page(mapping, index,
770 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
771 mapping_gfp_mask(mapping));
772 }
773
774 #define swapcache_index(folio) __page_file_index(&(folio)->page)
775
776 /**
777 * folio_index - File index of a folio.
778 * @folio: The folio.
779 *
780 * For a folio which is either in the page cache or the swap cache,
781 * return its index within the address_space it belongs to. If you know
782 * the page is definitely in the page cache, you can look at the folio's
783 * index directly.
784 *
785 * Return: The index (offset in units of pages) of a folio in its file.
786 */
folio_index(struct folio * folio)787 static inline pgoff_t folio_index(struct folio *folio)
788 {
789 if (unlikely(folio_test_swapcache(folio)))
790 return swapcache_index(folio);
791 return folio->index;
792 }
793
794 /**
795 * folio_next_index - Get the index of the next folio.
796 * @folio: The current folio.
797 *
798 * Return: The index of the folio which follows this folio in the file.
799 */
folio_next_index(struct folio * folio)800 static inline pgoff_t folio_next_index(struct folio *folio)
801 {
802 return folio->index + folio_nr_pages(folio);
803 }
804
805 /**
806 * folio_file_page - The page for a particular index.
807 * @folio: The folio which contains this index.
808 * @index: The index we want to look up.
809 *
810 * Sometimes after looking up a folio in the page cache, we need to
811 * obtain the specific page for an index (eg a page fault).
812 *
813 * Return: The page containing the file data for this index.
814 */
folio_file_page(struct folio * folio,pgoff_t index)815 static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
816 {
817 /* HugeTLBfs indexes the page cache in units of hpage_size */
818 if (folio_test_hugetlb(folio))
819 return &folio->page;
820 return folio_page(folio, index & (folio_nr_pages(folio) - 1));
821 }
822
823 /**
824 * folio_contains - Does this folio contain this index?
825 * @folio: The folio.
826 * @index: The page index within the file.
827 *
828 * Context: The caller should have the page locked in order to prevent
829 * (eg) shmem from moving the page between the page cache and swap cache
830 * and changing its index in the middle of the operation.
831 * Return: true or false.
832 */
folio_contains(struct folio * folio,pgoff_t index)833 static inline bool folio_contains(struct folio *folio, pgoff_t index)
834 {
835 /* HugeTLBfs indexes the page cache in units of hpage_size */
836 if (folio_test_hugetlb(folio))
837 return folio->index == index;
838 return index - folio_index(folio) < folio_nr_pages(folio);
839 }
840
841 /*
842 * Given the page we found in the page cache, return the page corresponding
843 * to this index in the file
844 */
find_subpage(struct page * head,pgoff_t index)845 static inline struct page *find_subpage(struct page *head, pgoff_t index)
846 {
847 /* HugeTLBfs wants the head page regardless */
848 if (PageHuge(head))
849 return head;
850
851 return head + (index & (thp_nr_pages(head) - 1));
852 }
853
854 unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
855 pgoff_t end, struct folio_batch *fbatch);
856 unsigned filemap_get_folios_contig(struct address_space *mapping,
857 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
858 unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start,
859 pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch);
860
861 struct page *grab_cache_page_write_begin(struct address_space *mapping,
862 pgoff_t index);
863
864 /*
865 * Returns locked page at given index in given cache, creating it if needed.
866 */
grab_cache_page(struct address_space * mapping,pgoff_t index)867 static inline struct page *grab_cache_page(struct address_space *mapping,
868 pgoff_t index)
869 {
870 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
871 }
872
873 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
874 filler_t *filler, struct file *file);
875 struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index,
876 gfp_t flags);
877 struct page *read_cache_page(struct address_space *, pgoff_t index,
878 filler_t *filler, struct file *file);
879 extern struct page * read_cache_page_gfp(struct address_space *mapping,
880 pgoff_t index, gfp_t gfp_mask);
881
read_mapping_page(struct address_space * mapping,pgoff_t index,struct file * file)882 static inline struct page *read_mapping_page(struct address_space *mapping,
883 pgoff_t index, struct file *file)
884 {
885 return read_cache_page(mapping, index, NULL, file);
886 }
887
read_mapping_folio(struct address_space * mapping,pgoff_t index,struct file * file)888 static inline struct folio *read_mapping_folio(struct address_space *mapping,
889 pgoff_t index, struct file *file)
890 {
891 return read_cache_folio(mapping, index, NULL, file);
892 }
893
894 /*
895 * Get index of the page within radix-tree (but not for hugetlb pages).
896 * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
897 */
page_to_index(struct page * page)898 static inline pgoff_t page_to_index(struct page *page)
899 {
900 struct page *head;
901
902 if (likely(!PageTransTail(page)))
903 return page->index;
904
905 head = compound_head(page);
906 /*
907 * We don't initialize ->index for tail pages: calculate based on
908 * head page
909 */
910 return head->index + page - head;
911 }
912
913 extern pgoff_t hugetlb_basepage_index(struct page *page);
914
915 /*
916 * Get the offset in PAGE_SIZE (even for hugetlb pages).
917 * (TODO: hugetlb pages should have ->index in PAGE_SIZE)
918 */
page_to_pgoff(struct page * page)919 static inline pgoff_t page_to_pgoff(struct page *page)
920 {
921 if (unlikely(PageHuge(page)))
922 return hugetlb_basepage_index(page);
923 return page_to_index(page);
924 }
925
926 /*
927 * Return byte-offset into filesystem object for page.
928 */
page_offset(struct page * page)929 static inline loff_t page_offset(struct page *page)
930 {
931 return ((loff_t)page->index) << PAGE_SHIFT;
932 }
933
page_file_offset(struct page * page)934 static inline loff_t page_file_offset(struct page *page)
935 {
936 return ((loff_t)page_index(page)) << PAGE_SHIFT;
937 }
938
939 /**
940 * folio_pos - Returns the byte position of this folio in its file.
941 * @folio: The folio.
942 */
folio_pos(struct folio * folio)943 static inline loff_t folio_pos(struct folio *folio)
944 {
945 return page_offset(&folio->page);
946 }
947
948 /**
949 * folio_file_pos - Returns the byte position of this folio in its file.
950 * @folio: The folio.
951 *
952 * This differs from folio_pos() for folios which belong to a swap file.
953 * NFS is the only filesystem today which needs to use folio_file_pos().
954 */
folio_file_pos(struct folio * folio)955 static inline loff_t folio_file_pos(struct folio *folio)
956 {
957 return page_file_offset(&folio->page);
958 }
959
960 /*
961 * Get the offset in PAGE_SIZE (even for hugetlb folios).
962 * (TODO: hugetlb folios should have ->index in PAGE_SIZE)
963 */
folio_pgoff(struct folio * folio)964 static inline pgoff_t folio_pgoff(struct folio *folio)
965 {
966 if (unlikely(folio_test_hugetlb(folio)))
967 return hugetlb_basepage_index(&folio->page);
968 return folio->index;
969 }
970
971 extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
972 unsigned long address);
973
linear_page_index(struct vm_area_struct * vma,unsigned long address)974 static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
975 unsigned long address)
976 {
977 pgoff_t pgoff;
978 if (unlikely(is_vm_hugetlb_page(vma)))
979 return linear_hugepage_index(vma, address);
980 pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
981 pgoff += vma->vm_pgoff;
982 return pgoff;
983 }
984
985 struct wait_page_key {
986 struct folio *folio;
987 int bit_nr;
988 int page_match;
989 };
990
991 struct wait_page_queue {
992 struct folio *folio;
993 int bit_nr;
994 wait_queue_entry_t wait;
995 };
996
wake_page_match(struct wait_page_queue * wait_page,struct wait_page_key * key)997 static inline bool wake_page_match(struct wait_page_queue *wait_page,
998 struct wait_page_key *key)
999 {
1000 if (wait_page->folio != key->folio)
1001 return false;
1002 key->page_match = 1;
1003
1004 if (wait_page->bit_nr != key->bit_nr)
1005 return false;
1006
1007 return true;
1008 }
1009
1010 void __folio_lock(struct folio *folio);
1011 int __folio_lock_killable(struct folio *folio);
1012 vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf);
1013 void unlock_page(struct page *page);
1014 void folio_unlock(struct folio *folio);
1015
1016 /**
1017 * folio_trylock() - Attempt to lock a folio.
1018 * @folio: The folio to attempt to lock.
1019 *
1020 * Sometimes it is undesirable to wait for a folio to be unlocked (eg
1021 * when the locks are being taken in the wrong order, or if making
1022 * progress through a batch of folios is more important than processing
1023 * them in order). Usually folio_lock() is the correct function to call.
1024 *
1025 * Context: Any context.
1026 * Return: Whether the lock was successfully acquired.
1027 */
folio_trylock(struct folio * folio)1028 static inline bool folio_trylock(struct folio *folio)
1029 {
1030 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
1031 }
1032
1033 /*
1034 * Return true if the page was successfully locked
1035 */
trylock_page(struct page * page)1036 static inline int trylock_page(struct page *page)
1037 {
1038 return folio_trylock(page_folio(page));
1039 }
1040
1041 /**
1042 * folio_lock() - Lock this folio.
1043 * @folio: The folio to lock.
1044 *
1045 * The folio lock protects against many things, probably more than it
1046 * should. It is primarily held while a folio is being brought uptodate,
1047 * either from its backing file or from swap. It is also held while a
1048 * folio is being truncated from its address_space, so holding the lock
1049 * is sufficient to keep folio->mapping stable.
1050 *
1051 * The folio lock is also held while write() is modifying the page to
1052 * provide POSIX atomicity guarantees (as long as the write does not
1053 * cross a page boundary). Other modifications to the data in the folio
1054 * do not hold the folio lock and can race with writes, eg DMA and stores
1055 * to mapped pages.
1056 *
1057 * Context: May sleep. If you need to acquire the locks of two or
1058 * more folios, they must be in order of ascending index, if they are
1059 * in the same address_space. If they are in different address_spaces,
1060 * acquire the lock of the folio which belongs to the address_space which
1061 * has the lowest address in memory first.
1062 */
folio_lock(struct folio * folio)1063 static inline void folio_lock(struct folio *folio)
1064 {
1065 might_sleep();
1066 if (!folio_trylock(folio))
1067 __folio_lock(folio);
1068 }
1069
1070 /**
1071 * lock_page() - Lock the folio containing this page.
1072 * @page: The page to lock.
1073 *
1074 * See folio_lock() for a description of what the lock protects.
1075 * This is a legacy function and new code should probably use folio_lock()
1076 * instead.
1077 *
1078 * Context: May sleep. Pages in the same folio share a lock, so do not
1079 * attempt to lock two pages which share a folio.
1080 */
lock_page(struct page * page)1081 static inline void lock_page(struct page *page)
1082 {
1083 struct folio *folio;
1084 might_sleep();
1085
1086 folio = page_folio(page);
1087 if (!folio_trylock(folio))
1088 __folio_lock(folio);
1089 }
1090
1091 /**
1092 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
1093 * @folio: The folio to lock.
1094 *
1095 * Attempts to lock the folio, like folio_lock(), except that the sleep
1096 * to acquire the lock is interruptible by a fatal signal.
1097 *
1098 * Context: May sleep; see folio_lock().
1099 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
1100 */
folio_lock_killable(struct folio * folio)1101 static inline int folio_lock_killable(struct folio *folio)
1102 {
1103 might_sleep();
1104 if (!folio_trylock(folio))
1105 return __folio_lock_killable(folio);
1106 return 0;
1107 }
1108
1109 /*
1110 * folio_lock_or_retry - Lock the folio, unless this would block and the
1111 * caller indicated that it can handle a retry.
1112 *
1113 * Return value and mmap_lock implications depend on flags; see
1114 * __folio_lock_or_retry().
1115 */
folio_lock_or_retry(struct folio * folio,struct vm_fault * vmf)1116 static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
1117 struct vm_fault *vmf)
1118 {
1119 might_sleep();
1120 if (!folio_trylock(folio))
1121 return __folio_lock_or_retry(folio, vmf);
1122 return 0;
1123 }
1124
1125 /*
1126 * This is exported only for folio_wait_locked/folio_wait_writeback, etc.,
1127 * and should not be used directly.
1128 */
1129 void folio_wait_bit(struct folio *folio, int bit_nr);
1130 int folio_wait_bit_killable(struct folio *folio, int bit_nr);
1131
1132 /*
1133 * Wait for a folio to be unlocked.
1134 *
1135 * This must be called with the caller "holding" the folio,
1136 * ie with increased folio reference count so that the folio won't
1137 * go away during the wait.
1138 */
folio_wait_locked(struct folio * folio)1139 static inline void folio_wait_locked(struct folio *folio)
1140 {
1141 if (folio_test_locked(folio))
1142 folio_wait_bit(folio, PG_locked);
1143 }
1144
folio_wait_locked_killable(struct folio * folio)1145 static inline int folio_wait_locked_killable(struct folio *folio)
1146 {
1147 if (!folio_test_locked(folio))
1148 return 0;
1149 return folio_wait_bit_killable(folio, PG_locked);
1150 }
1151
wait_on_page_locked(struct page * page)1152 static inline void wait_on_page_locked(struct page *page)
1153 {
1154 folio_wait_locked(page_folio(page));
1155 }
1156
1157 void wait_on_page_writeback(struct page *page);
1158 void folio_wait_writeback(struct folio *folio);
1159 int folio_wait_writeback_killable(struct folio *folio);
1160 void end_page_writeback(struct page *page);
1161 void folio_end_writeback(struct folio *folio);
1162 void wait_for_stable_page(struct page *page);
1163 void folio_wait_stable(struct folio *folio);
1164 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
__set_page_dirty(struct page * page,struct address_space * mapping,int warn)1165 static inline void __set_page_dirty(struct page *page,
1166 struct address_space *mapping, int warn)
1167 {
1168 __folio_mark_dirty(page_folio(page), mapping, warn);
1169 }
1170 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
1171 void __folio_cancel_dirty(struct folio *folio);
folio_cancel_dirty(struct folio * folio)1172 static inline void folio_cancel_dirty(struct folio *folio)
1173 {
1174 /* Avoid atomic ops, locking, etc. when not actually needed. */
1175 if (folio_test_dirty(folio))
1176 __folio_cancel_dirty(folio);
1177 }
1178 bool folio_clear_dirty_for_io(struct folio *folio);
1179 bool clear_page_dirty_for_io(struct page *page);
1180 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
1181 int __set_page_dirty_nobuffers(struct page *page);
1182 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
1183
1184 #ifdef CONFIG_MIGRATION
1185 int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
1186 struct folio *src, enum migrate_mode mode);
1187 #else
1188 #define filemap_migrate_folio NULL
1189 #endif
1190 void folio_end_private_2(struct folio *folio);
1191 void folio_wait_private_2(struct folio *folio);
1192 int folio_wait_private_2_killable(struct folio *folio);
1193
1194 /*
1195 * Add an arbitrary waiter to a page's wait queue
1196 */
1197 void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter);
1198
1199 /*
1200 * Fault in userspace address range.
1201 */
1202 size_t fault_in_writeable(char __user *uaddr, size_t size);
1203 size_t fault_in_subpage_writeable(char __user *uaddr, size_t size);
1204 size_t fault_in_safe_writeable(const char __user *uaddr, size_t size);
1205 size_t fault_in_readable(const char __user *uaddr, size_t size);
1206
1207 int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
1208 pgoff_t index, gfp_t gfp);
1209 int filemap_add_folio(struct address_space *mapping, struct folio *folio,
1210 pgoff_t index, gfp_t gfp);
1211 void filemap_remove_folio(struct folio *folio);
1212 void __filemap_remove_folio(struct folio *folio, void *shadow);
1213 void replace_page_cache_folio(struct folio *old, struct folio *new);
1214 void delete_from_page_cache_batch(struct address_space *mapping,
1215 struct folio_batch *fbatch);
1216 bool filemap_release_folio(struct folio *folio, gfp_t gfp);
1217 loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end,
1218 int whence);
1219
1220 /* Must be non-static for BPF error injection */
1221 int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
1222 pgoff_t index, gfp_t gfp, void **shadowp);
1223
1224 bool filemap_range_has_writeback(struct address_space *mapping,
1225 loff_t start_byte, loff_t end_byte);
1226
1227 /**
1228 * filemap_range_needs_writeback - check if range potentially needs writeback
1229 * @mapping: address space within which to check
1230 * @start_byte: offset in bytes where the range starts
1231 * @end_byte: offset in bytes where the range ends (inclusive)
1232 *
1233 * Find at least one page in the range supplied, usually used to check if
1234 * direct writing in this range will trigger a writeback. Used by O_DIRECT
1235 * read/write with IOCB_NOWAIT, to see if the caller needs to do
1236 * filemap_write_and_wait_range() before proceeding.
1237 *
1238 * Return: %true if the caller should do filemap_write_and_wait_range() before
1239 * doing O_DIRECT to a page in this range, %false otherwise.
1240 */
filemap_range_needs_writeback(struct address_space * mapping,loff_t start_byte,loff_t end_byte)1241 static inline bool filemap_range_needs_writeback(struct address_space *mapping,
1242 loff_t start_byte,
1243 loff_t end_byte)
1244 {
1245 if (!mapping->nrpages)
1246 return false;
1247 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
1248 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
1249 return false;
1250 return filemap_range_has_writeback(mapping, start_byte, end_byte);
1251 }
1252
1253 /**
1254 * struct readahead_control - Describes a readahead request.
1255 *
1256 * A readahead request is for consecutive pages. Filesystems which
1257 * implement the ->readahead method should call readahead_page() or
1258 * readahead_page_batch() in a loop and attempt to start I/O against
1259 * each page in the request.
1260 *
1261 * Most of the fields in this struct are private and should be accessed
1262 * by the functions below.
1263 *
1264 * @file: The file, used primarily by network filesystems for authentication.
1265 * May be NULL if invoked internally by the filesystem.
1266 * @mapping: Readahead this filesystem object.
1267 * @ra: File readahead state. May be NULL.
1268 */
1269 struct readahead_control {
1270 struct file *file;
1271 struct address_space *mapping;
1272 struct file_ra_state *ra;
1273 /* private: use the readahead_* accessors instead */
1274 pgoff_t _index;
1275 unsigned int _nr_pages;
1276 unsigned int _batch_count;
1277 bool _workingset;
1278 unsigned long _pflags;
1279 };
1280
1281 #define DEFINE_READAHEAD(ractl, f, r, m, i) \
1282 struct readahead_control ractl = { \
1283 .file = f, \
1284 .mapping = m, \
1285 .ra = r, \
1286 ._index = i, \
1287 }
1288
1289 #define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
1290
1291 void page_cache_ra_unbounded(struct readahead_control *,
1292 unsigned long nr_to_read, unsigned long lookahead_count);
1293 void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
1294 void page_cache_async_ra(struct readahead_control *, struct folio *,
1295 unsigned long req_count);
1296 void readahead_expand(struct readahead_control *ractl,
1297 loff_t new_start, size_t new_len);
1298
1299 /**
1300 * page_cache_sync_readahead - generic file readahead
1301 * @mapping: address_space which holds the pagecache and I/O vectors
1302 * @ra: file_ra_state which holds the readahead state
1303 * @file: Used by the filesystem for authentication.
1304 * @index: Index of first page to be read.
1305 * @req_count: Total number of pages being read by the caller.
1306 *
1307 * page_cache_sync_readahead() should be called when a cache miss happened:
1308 * it will submit the read. The readahead logic may decide to piggyback more
1309 * pages onto the read request if access patterns suggest it will improve
1310 * performance.
1311 */
1312 static inline
page_cache_sync_readahead(struct address_space * mapping,struct file_ra_state * ra,struct file * file,pgoff_t index,unsigned long req_count)1313 void page_cache_sync_readahead(struct address_space *mapping,
1314 struct file_ra_state *ra, struct file *file, pgoff_t index,
1315 unsigned long req_count)
1316 {
1317 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1318 page_cache_sync_ra(&ractl, req_count);
1319 }
1320
1321 /**
1322 * page_cache_async_readahead - file readahead for marked pages
1323 * @mapping: address_space which holds the pagecache and I/O vectors
1324 * @ra: file_ra_state which holds the readahead state
1325 * @file: Used by the filesystem for authentication.
1326 * @folio: The folio at @index which triggered the readahead call.
1327 * @index: Index of first page to be read.
1328 * @req_count: Total number of pages being read by the caller.
1329 *
1330 * page_cache_async_readahead() should be called when a page is used which
1331 * is marked as PageReadahead; this is a marker to suggest that the application
1332 * has used up enough of the readahead window that we should start pulling in
1333 * more pages.
1334 */
1335 static inline
page_cache_async_readahead(struct address_space * mapping,struct file_ra_state * ra,struct file * file,struct folio * folio,pgoff_t index,unsigned long req_count)1336 void page_cache_async_readahead(struct address_space *mapping,
1337 struct file_ra_state *ra, struct file *file,
1338 struct folio *folio, pgoff_t index, unsigned long req_count)
1339 {
1340 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1341 page_cache_async_ra(&ractl, folio, req_count);
1342 }
1343
__readahead_folio(struct readahead_control * ractl)1344 static inline struct folio *__readahead_folio(struct readahead_control *ractl)
1345 {
1346 struct folio *folio;
1347
1348 BUG_ON(ractl->_batch_count > ractl->_nr_pages);
1349 ractl->_nr_pages -= ractl->_batch_count;
1350 ractl->_index += ractl->_batch_count;
1351
1352 if (!ractl->_nr_pages) {
1353 ractl->_batch_count = 0;
1354 return NULL;
1355 }
1356
1357 folio = xa_load(&ractl->mapping->i_pages, ractl->_index);
1358 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
1359 ractl->_batch_count = folio_nr_pages(folio);
1360
1361 return folio;
1362 }
1363
1364 /**
1365 * readahead_page - Get the next page to read.
1366 * @ractl: The current readahead request.
1367 *
1368 * Context: The page is locked and has an elevated refcount. The caller
1369 * should decreases the refcount once the page has been submitted for I/O
1370 * and unlock the page once all I/O to that page has completed.
1371 * Return: A pointer to the next page, or %NULL if we are done.
1372 */
readahead_page(struct readahead_control * ractl)1373 static inline struct page *readahead_page(struct readahead_control *ractl)
1374 {
1375 struct folio *folio = __readahead_folio(ractl);
1376
1377 return &folio->page;
1378 }
1379
1380 /**
1381 * readahead_folio - Get the next folio to read.
1382 * @ractl: The current readahead request.
1383 *
1384 * Context: The folio is locked. The caller should unlock the folio once
1385 * all I/O to that folio has completed.
1386 * Return: A pointer to the next folio, or %NULL if we are done.
1387 */
readahead_folio(struct readahead_control * ractl)1388 static inline struct folio *readahead_folio(struct readahead_control *ractl)
1389 {
1390 struct folio *folio = __readahead_folio(ractl);
1391
1392 if (folio)
1393 folio_put(folio);
1394 return folio;
1395 }
1396
__readahead_batch(struct readahead_control * rac,struct page ** array,unsigned int array_sz)1397 static inline unsigned int __readahead_batch(struct readahead_control *rac,
1398 struct page **array, unsigned int array_sz)
1399 {
1400 unsigned int i = 0;
1401 XA_STATE(xas, &rac->mapping->i_pages, 0);
1402 struct page *page;
1403
1404 BUG_ON(rac->_batch_count > rac->_nr_pages);
1405 rac->_nr_pages -= rac->_batch_count;
1406 rac->_index += rac->_batch_count;
1407 rac->_batch_count = 0;
1408
1409 xas_set(&xas, rac->_index);
1410 rcu_read_lock();
1411 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
1412 if (xas_retry(&xas, page))
1413 continue;
1414 VM_BUG_ON_PAGE(!PageLocked(page), page);
1415 VM_BUG_ON_PAGE(PageTail(page), page);
1416 array[i++] = page;
1417 rac->_batch_count += thp_nr_pages(page);
1418 if (i == array_sz)
1419 break;
1420 }
1421 rcu_read_unlock();
1422
1423 return i;
1424 }
1425
1426 /**
1427 * readahead_page_batch - Get a batch of pages to read.
1428 * @rac: The current readahead request.
1429 * @array: An array of pointers to struct page.
1430 *
1431 * Context: The pages are locked and have an elevated refcount. The caller
1432 * should decreases the refcount once the page has been submitted for I/O
1433 * and unlock the page once all I/O to that page has completed.
1434 * Return: The number of pages placed in the array. 0 indicates the request
1435 * is complete.
1436 */
1437 #define readahead_page_batch(rac, array) \
1438 __readahead_batch(rac, array, ARRAY_SIZE(array))
1439
1440 /**
1441 * readahead_pos - The byte offset into the file of this readahead request.
1442 * @rac: The readahead request.
1443 */
readahead_pos(struct readahead_control * rac)1444 static inline loff_t readahead_pos(struct readahead_control *rac)
1445 {
1446 return (loff_t)rac->_index * PAGE_SIZE;
1447 }
1448
1449 /**
1450 * readahead_length - The number of bytes in this readahead request.
1451 * @rac: The readahead request.
1452 */
readahead_length(struct readahead_control * rac)1453 static inline size_t readahead_length(struct readahead_control *rac)
1454 {
1455 return rac->_nr_pages * PAGE_SIZE;
1456 }
1457
1458 /**
1459 * readahead_index - The index of the first page in this readahead request.
1460 * @rac: The readahead request.
1461 */
readahead_index(struct readahead_control * rac)1462 static inline pgoff_t readahead_index(struct readahead_control *rac)
1463 {
1464 return rac->_index;
1465 }
1466
1467 /**
1468 * readahead_count - The number of pages in this readahead request.
1469 * @rac: The readahead request.
1470 */
readahead_count(struct readahead_control * rac)1471 static inline unsigned int readahead_count(struct readahead_control *rac)
1472 {
1473 return rac->_nr_pages;
1474 }
1475
1476 /**
1477 * readahead_batch_length - The number of bytes in the current batch.
1478 * @rac: The readahead request.
1479 */
readahead_batch_length(struct readahead_control * rac)1480 static inline size_t readahead_batch_length(struct readahead_control *rac)
1481 {
1482 return rac->_batch_count * PAGE_SIZE;
1483 }
1484
dir_pages(struct inode * inode)1485 static inline unsigned long dir_pages(struct inode *inode)
1486 {
1487 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
1488 PAGE_SHIFT;
1489 }
1490
1491 /**
1492 * folio_mkwrite_check_truncate - check if folio was truncated
1493 * @folio: the folio to check
1494 * @inode: the inode to check the folio against
1495 *
1496 * Return: the number of bytes in the folio up to EOF,
1497 * or -EFAULT if the folio was truncated.
1498 */
folio_mkwrite_check_truncate(struct folio * folio,struct inode * inode)1499 static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
1500 struct inode *inode)
1501 {
1502 loff_t size = i_size_read(inode);
1503 pgoff_t index = size >> PAGE_SHIFT;
1504 size_t offset = offset_in_folio(folio, size);
1505
1506 if (!folio->mapping)
1507 return -EFAULT;
1508
1509 /* folio is wholly inside EOF */
1510 if (folio_next_index(folio) - 1 < index)
1511 return folio_size(folio);
1512 /* folio is wholly past EOF */
1513 if (folio->index > index || !offset)
1514 return -EFAULT;
1515 /* folio is partially inside EOF */
1516 return offset;
1517 }
1518
1519 /**
1520 * page_mkwrite_check_truncate - check if page was truncated
1521 * @page: the page to check
1522 * @inode: the inode to check the page against
1523 *
1524 * Returns the number of bytes in the page up to EOF,
1525 * or -EFAULT if the page was truncated.
1526 */
page_mkwrite_check_truncate(struct page * page,struct inode * inode)1527 static inline int page_mkwrite_check_truncate(struct page *page,
1528 struct inode *inode)
1529 {
1530 loff_t size = i_size_read(inode);
1531 pgoff_t index = size >> PAGE_SHIFT;
1532 int offset = offset_in_page(size);
1533
1534 if (page->mapping != inode->i_mapping)
1535 return -EFAULT;
1536
1537 /* page is wholly inside EOF */
1538 if (page->index < index)
1539 return PAGE_SIZE;
1540 /* page is wholly past EOF */
1541 if (page->index > index || !offset)
1542 return -EFAULT;
1543 /* page is partially inside EOF */
1544 return offset;
1545 }
1546
1547 /**
1548 * i_blocks_per_folio - How many blocks fit in this folio.
1549 * @inode: The inode which contains the blocks.
1550 * @folio: The folio.
1551 *
1552 * If the block size is larger than the size of this folio, return zero.
1553 *
1554 * Context: The caller should hold a refcount on the folio to prevent it
1555 * from being split.
1556 * Return: The number of filesystem blocks covered by this folio.
1557 */
1558 static inline
i_blocks_per_folio(struct inode * inode,struct folio * folio)1559 unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
1560 {
1561 return folio_size(folio) >> inode->i_blkbits;
1562 }
1563
1564 static inline
i_blocks_per_page(struct inode * inode,struct page * page)1565 unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
1566 {
1567 return i_blocks_per_folio(inode, page_folio(page));
1568 }
1569 #endif /* _LINUX_PAGEMAP_H */
1570