1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PAGEMAP_H
3 #define _LINUX_PAGEMAP_H
6 * Copyright 1995 Linus Torvalds
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>
21 unsigned long invalidate_mapping_pages(struct address_space *mapping,
22 pgoff_t start, pgoff_t end);
24 static inline void invalidate_remote_inode(struct inode *inode)
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);
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);
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);
44 static inline int filemap_fdatawait(struct address_space *mapping)
46 return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
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);
62 static inline int filemap_write_and_wait(struct address_space *mapping)
64 return filemap_write_and_wait_range(mapping, 0, LLONG_MAX);
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
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.
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.
81 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
83 /* Fastpath for common case of no error */
85 __filemap_set_wb_err(mapping, err);
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
93 * Grab the errseq_t value from the mapping, and see if it has changed "since"
94 * the given value was sampled.
96 * If it has then report the latest error set, otherwise return 0.
98 static inline int filemap_check_wb_err(struct address_space *mapping,
101 return errseq_check(&mapping->wb_err, since);
105 * filemap_sample_wb_err - sample the current errseq_t to test for later errors
106 * @mapping: mapping to be sampled
108 * Writeback errors are always reported relative to a particular sample point
109 * in the past. This function provides those sample points.
111 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
113 return errseq_sample(&mapping->wb_err);
117 * file_sample_sb_err - sample the current errseq_t to test for later errors
118 * @file: file pointer to be sampled
120 * Grab the most current superblock-level errseq_t value for the given
123 static inline errseq_t file_sample_sb_err(struct file *file)
125 return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err);
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
133 static inline int inode_drain_writes(struct inode *inode)
135 inode_dio_wait(inode);
136 return filemap_write_and_wait(inode->i_mapping);
139 static inline bool mapping_empty(struct address_space *mapping)
141 return xa_empty(&mapping->i_pages);
145 * mapping_shrinkable - test if page cache state allows inode reclaim
146 * @mapping: the page cache mapping
148 * This checks the mapping's cache state for the pupose of inode
149 * reclaim and LRU management.
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.
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.
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.
165 static inline bool mapping_shrinkable(struct address_space *mapping)
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.
174 if (IS_ENABLED(CONFIG_HIGHMEM))
177 /* Cache completely empty? Shrink away. */
178 head = rcu_access_pointer(mapping->i_pages.xa_head);
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.
188 if (!xa_is_node(head) && xa_is_value(head))
195 * Bits in 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
209 AS_UNMOVABLE, /* The mapping cannot be moved, ever */
213 * mapping_set_error - record a writeback error in the address_space
214 * @mapping: the mapping in which an error should be set
215 * @error: the error to set in the mapping
217 * When writeback fails in some way, we must record that error so that
218 * userspace can be informed when fsync and the like are called. We endeavor
219 * to report errors on any file that was open at the time of the error. Some
220 * internal callers also need to know when writeback errors have occurred.
222 * When a writeback error occurs, most filesystems will want to call
223 * mapping_set_error to record the error in the mapping so that it can be
224 * reported when the application calls fsync(2).
226 static inline void mapping_set_error(struct address_space *mapping, int error)
231 /* Record in wb_err for checkers using errseq_t based tracking */
232 __filemap_set_wb_err(mapping, error);
234 /* Record it in superblock */
236 errseq_set(&mapping->host->i_sb->s_wb_err, error);
238 /* Record it in flags for now, for legacy callers */
239 if (error == -ENOSPC)
240 set_bit(AS_ENOSPC, &mapping->flags);
242 set_bit(AS_EIO, &mapping->flags);
245 static inline void mapping_set_unevictable(struct address_space *mapping)
247 set_bit(AS_UNEVICTABLE, &mapping->flags);
250 static inline void mapping_clear_unevictable(struct address_space *mapping)
252 clear_bit(AS_UNEVICTABLE, &mapping->flags);
255 static inline bool mapping_unevictable(struct address_space *mapping)
257 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags);
260 static inline void mapping_set_exiting(struct address_space *mapping)
262 set_bit(AS_EXITING, &mapping->flags);
265 static inline int mapping_exiting(struct address_space *mapping)
267 return test_bit(AS_EXITING, &mapping->flags);
270 static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
272 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
275 static inline int mapping_use_writeback_tags(struct address_space *mapping)
277 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
280 static inline bool mapping_release_always(const struct address_space *mapping)
282 return test_bit(AS_RELEASE_ALWAYS, &mapping->flags);
285 static inline void mapping_set_release_always(struct address_space *mapping)
287 set_bit(AS_RELEASE_ALWAYS, &mapping->flags);
290 static inline void mapping_clear_release_always(struct address_space *mapping)
292 clear_bit(AS_RELEASE_ALWAYS, &mapping->flags);
295 static inline bool mapping_stable_writes(const struct address_space *mapping)
297 return test_bit(AS_STABLE_WRITES, &mapping->flags);
300 static inline void mapping_set_stable_writes(struct address_space *mapping)
302 set_bit(AS_STABLE_WRITES, &mapping->flags);
305 static inline void mapping_clear_stable_writes(struct address_space *mapping)
307 clear_bit(AS_STABLE_WRITES, &mapping->flags);
310 static inline void mapping_set_unmovable(struct address_space *mapping)
313 * It's expected unmovable mappings are also unevictable. Compaction
314 * migrate scanner (isolate_migratepages_block()) relies on this to
315 * reduce page locking.
317 set_bit(AS_UNEVICTABLE, &mapping->flags);
318 set_bit(AS_UNMOVABLE, &mapping->flags);
321 static inline bool mapping_unmovable(struct address_space *mapping)
323 return test_bit(AS_UNMOVABLE, &mapping->flags);
326 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
328 return mapping->gfp_mask;
331 /* Restricts the given gfp_mask to what the mapping allows. */
332 static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
335 return mapping_gfp_mask(mapping) & gfp_mask;
339 * This is non-atomic. Only to be used before the mapping is activated.
340 * Probably needs a barrier...
342 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
348 * mapping_set_large_folios() - Indicate the file supports large folios.
349 * @mapping: The file.
351 * The filesystem should call this function in its inode constructor to
352 * indicate that the VFS can use large folios to cache the contents of
355 * Context: This should not be called while the inode is active as it
358 static inline void mapping_set_large_folios(struct address_space *mapping)
360 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
364 * Large folio support currently depends on THP. These dependencies are
365 * being worked on but are not yet fixed.
367 static inline bool mapping_large_folio_support(struct address_space *mapping)
369 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
370 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
373 static inline int filemap_nr_thps(struct address_space *mapping)
375 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
376 return atomic_read(&mapping->nr_thps);
382 static inline void filemap_nr_thps_inc(struct address_space *mapping)
384 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
385 if (!mapping_large_folio_support(mapping))
386 atomic_inc(&mapping->nr_thps);
388 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
392 static inline void filemap_nr_thps_dec(struct address_space *mapping)
394 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
395 if (!mapping_large_folio_support(mapping))
396 atomic_dec(&mapping->nr_thps);
398 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
402 struct address_space *page_mapping(struct page *);
403 struct address_space *folio_mapping(struct folio *);
404 struct address_space *swapcache_mapping(struct folio *);
407 * folio_file_mapping - Find the mapping this folio belongs to.
410 * For folios which are in the page cache, return the mapping that this
411 * page belongs to. Folios in the swap cache return the mapping of the
412 * swap file or swap device where the data is stored. This is different
413 * from the mapping returned by folio_mapping(). The only reason to
414 * use it is if, like NFS, you return 0 from ->activate_swapfile.
416 * Do not call this for folios which aren't in the page cache or swap cache.
418 static inline struct address_space *folio_file_mapping(struct folio *folio)
420 if (unlikely(folio_test_swapcache(folio)))
421 return swapcache_mapping(folio);
423 return folio->mapping;
427 * folio_flush_mapping - Find the file mapping this folio belongs to.
430 * For folios which are in the page cache, return the mapping that this
431 * page belongs to. Anonymous folios return NULL, even if they're in
432 * the swap cache. Other kinds of folio also return NULL.
434 * This is ONLY used by architecture cache flushing code. If you aren't
435 * writing cache flushing code, you want either folio_mapping() or
436 * folio_file_mapping().
438 static inline struct address_space *folio_flush_mapping(struct folio *folio)
440 if (unlikely(folio_test_swapcache(folio)))
443 return folio_mapping(folio);
446 static inline struct address_space *page_file_mapping(struct page *page)
448 return folio_file_mapping(page_folio(page));
452 * folio_inode - Get the host inode for this folio.
455 * For folios which are in the page cache, return the inode that this folio
458 * Do not call this for folios which aren't in the page cache.
460 static inline struct inode *folio_inode(struct folio *folio)
462 return folio->mapping->host;
466 * folio_attach_private - Attach private data to a folio.
467 * @folio: Folio to attach data to.
468 * @data: Data to attach to folio.
470 * Attaching private data to a folio increments the page's reference count.
471 * The data must be detached before the folio will be freed.
473 static inline void folio_attach_private(struct folio *folio, void *data)
476 folio->private = data;
477 folio_set_private(folio);
481 * folio_change_private - Change private data on a folio.
482 * @folio: Folio to change the data on.
483 * @data: Data to set on the folio.
485 * Change the private data attached to a folio and return the old
486 * data. The page must previously have had data attached and the data
487 * must be detached before the folio will be freed.
489 * Return: Data that was previously attached to the folio.
491 static inline void *folio_change_private(struct folio *folio, void *data)
493 void *old = folio_get_private(folio);
495 folio->private = data;
500 * folio_detach_private - Detach private data from a folio.
501 * @folio: Folio to detach data from.
503 * Removes the data that was previously attached to the folio and decrements
504 * the refcount on the page.
506 * Return: Data that was attached to the folio.
508 static inline void *folio_detach_private(struct folio *folio)
510 void *data = folio_get_private(folio);
512 if (!folio_test_private(folio))
514 folio_clear_private(folio);
515 folio->private = NULL;
521 static inline void attach_page_private(struct page *page, void *data)
523 folio_attach_private(page_folio(page), data);
526 static inline void *detach_page_private(struct page *page)
528 return folio_detach_private(page_folio(page));
532 * There are some parts of the kernel which assume that PMD entries
533 * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then,
534 * limit the maximum allocation order to PMD size. I'm not aware of any
535 * assumptions about maximum order if THP are disabled, but 8 seems like
536 * a good order (that's 1MB if you're using 4kB pages)
538 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
539 #define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER
541 #define MAX_PAGECACHE_ORDER 8
545 struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
547 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
549 return folio_alloc(gfp, order);
553 static inline struct page *__page_cache_alloc(gfp_t gfp)
555 return &filemap_alloc_folio(gfp, 0)->page;
558 static inline struct page *page_cache_alloc(struct address_space *x)
560 return __page_cache_alloc(mapping_gfp_mask(x));
563 static inline gfp_t readahead_gfp_mask(struct address_space *x)
565 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
568 typedef int filler_t(struct file *, struct folio *);
570 pgoff_t page_cache_next_miss(struct address_space *mapping,
571 pgoff_t index, unsigned long max_scan);
572 pgoff_t page_cache_prev_miss(struct address_space *mapping,
573 pgoff_t index, unsigned long max_scan);
576 * typedef fgf_t - Flags for getting folios from the page cache.
578 * Most users of the page cache will not need to use these flags;
579 * there are convenience functions such as filemap_get_folio() and
580 * filemap_lock_folio(). For users which need more control over exactly
581 * what is done with the folios, these flags to __filemap_get_folio()
584 * * %FGP_ACCESSED - The folio will be marked accessed.
585 * * %FGP_LOCK - The folio is returned locked.
586 * * %FGP_CREAT - If no folio is present then a new folio is allocated,
587 * added to the page cache and the VM's LRU list. The folio is
589 * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the
590 * folio is already in cache. If the folio was allocated, unlock it
591 * before returning so the caller can do the same dance.
592 * * %FGP_WRITE - The folio will be written to by the caller.
593 * * %FGP_NOFS - __GFP_FS will get cleared in gfp.
594 * * %FGP_NOWAIT - Don't block on the folio lock.
595 * * %FGP_STABLE - Wait for the folio to be stable (finished writeback)
596 * * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin()
599 typedef unsigned int __bitwise fgf_t;
601 #define FGP_ACCESSED ((__force fgf_t)0x00000001)
602 #define FGP_LOCK ((__force fgf_t)0x00000002)
603 #define FGP_CREAT ((__force fgf_t)0x00000004)
604 #define FGP_WRITE ((__force fgf_t)0x00000008)
605 #define FGP_NOFS ((__force fgf_t)0x00000010)
606 #define FGP_NOWAIT ((__force fgf_t)0x00000020)
607 #define FGP_FOR_MMAP ((__force fgf_t)0x00000040)
608 #define FGP_STABLE ((__force fgf_t)0x00000080)
609 #define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */
611 #define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
614 * fgf_set_order - Encode a length in the fgf_t flags.
615 * @size: The suggested size of the folio to create.
617 * The caller of __filemap_get_folio() can use this to suggest a preferred
618 * size for the folio that is created. If there is already a folio at
619 * the index, it will be returned, no matter what its size. If a folio
620 * is freshly created, it may be of a different size than requested
621 * due to alignment constraints, memory pressure, or the presence of
622 * other folios at nearby indices.
624 static inline fgf_t fgf_set_order(size_t size)
626 unsigned int shift = ilog2(size);
628 if (shift <= PAGE_SHIFT)
630 return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
633 void *filemap_get_entry(struct address_space *mapping, pgoff_t index);
634 struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
635 fgf_t fgp_flags, gfp_t gfp);
636 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
637 fgf_t fgp_flags, gfp_t gfp);
640 * filemap_get_folio - Find and get a folio.
641 * @mapping: The address_space to search.
642 * @index: The page index.
644 * Looks up the page cache entry at @mapping & @index. If a folio is
645 * present, it is returned with an increased refcount.
647 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
648 * this index. Will not return a shadow, swap or DAX entry.
650 static inline struct folio *filemap_get_folio(struct address_space *mapping,
653 return __filemap_get_folio(mapping, index, 0, 0);
657 * filemap_lock_folio - Find and lock a folio.
658 * @mapping: The address_space to search.
659 * @index: The page index.
661 * Looks up the page cache entry at @mapping & @index. If a folio is
662 * present, it is returned locked with an increased refcount.
664 * Context: May sleep.
665 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
666 * this index. Will not return a shadow, swap or DAX entry.
668 static inline struct folio *filemap_lock_folio(struct address_space *mapping,
671 return __filemap_get_folio(mapping, index, FGP_LOCK, 0);
675 * filemap_grab_folio - grab a folio from the page cache
676 * @mapping: The address space to search
677 * @index: The page index
679 * Looks up the page cache entry at @mapping & @index. If no folio is found,
680 * a new folio is created. The folio is locked, marked as accessed, and
683 * Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found
684 * and failed to create a folio.
686 static inline struct folio *filemap_grab_folio(struct address_space *mapping,
689 return __filemap_get_folio(mapping, index,
690 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
691 mapping_gfp_mask(mapping));
695 * find_get_page - find and get a page reference
696 * @mapping: the address_space to search
697 * @offset: the page index
699 * Looks up the page cache slot at @mapping & @offset. If there is a
700 * page cache page, it is returned with an increased refcount.
702 * Otherwise, %NULL is returned.
704 static inline struct page *find_get_page(struct address_space *mapping,
707 return pagecache_get_page(mapping, offset, 0, 0);
710 static inline struct page *find_get_page_flags(struct address_space *mapping,
711 pgoff_t offset, fgf_t fgp_flags)
713 return pagecache_get_page(mapping, offset, fgp_flags, 0);
717 * find_lock_page - locate, pin and lock a pagecache page
718 * @mapping: the address_space to search
719 * @index: the page index
721 * Looks up the page cache entry at @mapping & @index. If there is a
722 * page cache page, it is returned locked and with an increased
725 * Context: May sleep.
726 * Return: A struct page or %NULL if there is no page in the cache for this
729 static inline struct page *find_lock_page(struct address_space *mapping,
732 return pagecache_get_page(mapping, index, FGP_LOCK, 0);
736 * find_or_create_page - locate or add a pagecache page
737 * @mapping: the page's address_space
738 * @index: the page's index into the mapping
739 * @gfp_mask: page allocation mode
741 * Looks up the page cache slot at @mapping & @offset. If there is a
742 * page cache page, it is returned locked and with an increased
745 * If the page is not present, a new page is allocated using @gfp_mask
746 * and added to the page cache and the VM's LRU list. The page is
747 * returned locked and with an increased refcount.
749 * On memory exhaustion, %NULL is returned.
751 * find_or_create_page() may sleep, even if @gfp_flags specifies an
754 static inline struct page *find_or_create_page(struct address_space *mapping,
755 pgoff_t index, gfp_t gfp_mask)
757 return pagecache_get_page(mapping, index,
758 FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
763 * grab_cache_page_nowait - returns locked page at given index in given cache
764 * @mapping: target address_space
765 * @index: the page index
767 * Same as grab_cache_page(), but do not wait if the page is unavailable.
768 * This is intended for speculative data generators, where the data can
769 * be regenerated if the page couldn't be grabbed. This routine should
770 * be safe to call while holding the lock for another page.
772 * Clear __GFP_FS when allocating the page to avoid recursion into the fs
773 * and deadlock against the caller's locked page.
775 static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
778 return pagecache_get_page(mapping, index,
779 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
780 mapping_gfp_mask(mapping));
783 #define swapcache_index(folio) __page_file_index(&(folio)->page)
786 * folio_index - File index of a folio.
789 * For a folio which is either in the page cache or the swap cache,
790 * return its index within the address_space it belongs to. If you know
791 * the page is definitely in the page cache, you can look at the folio's
794 * Return: The index (offset in units of pages) of a folio in its file.
796 static inline pgoff_t folio_index(struct folio *folio)
798 if (unlikely(folio_test_swapcache(folio)))
799 return swapcache_index(folio);
804 * folio_next_index - Get the index of the next folio.
805 * @folio: The current folio.
807 * Return: The index of the folio which follows this folio in the file.
809 static inline pgoff_t folio_next_index(struct folio *folio)
811 return folio->index + folio_nr_pages(folio);
815 * folio_file_page - The page for a particular index.
816 * @folio: The folio which contains this index.
817 * @index: The index we want to look up.
819 * Sometimes after looking up a folio in the page cache, we need to
820 * obtain the specific page for an index (eg a page fault).
822 * Return: The page containing the file data for this index.
824 static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
826 return folio_page(folio, index & (folio_nr_pages(folio) - 1));
830 * folio_contains - Does this folio contain this index?
832 * @index: The page index within the file.
834 * Context: The caller should have the page locked in order to prevent
835 * (eg) shmem from moving the page between the page cache and swap cache
836 * and changing its index in the middle of the operation.
837 * Return: true or false.
839 static inline bool folio_contains(struct folio *folio, pgoff_t index)
841 return index - folio_index(folio) < folio_nr_pages(folio);
845 * Given the page we found in the page cache, return the page corresponding
846 * to this index in the file
848 static inline struct page *find_subpage(struct page *head, pgoff_t index)
850 /* HugeTLBfs wants the head page regardless */
854 return head + (index & (thp_nr_pages(head) - 1));
857 unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
858 pgoff_t end, struct folio_batch *fbatch);
859 unsigned filemap_get_folios_contig(struct address_space *mapping,
860 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
861 unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start,
862 pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch);
864 struct page *grab_cache_page_write_begin(struct address_space *mapping,
868 * Returns locked page at given index in given cache, creating it if needed.
870 static inline struct page *grab_cache_page(struct address_space *mapping,
873 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
876 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
877 filler_t *filler, struct file *file);
878 struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index,
880 struct page *read_cache_page(struct address_space *, pgoff_t index,
881 filler_t *filler, struct file *file);
882 extern struct page * read_cache_page_gfp(struct address_space *mapping,
883 pgoff_t index, gfp_t gfp_mask);
885 static inline struct page *read_mapping_page(struct address_space *mapping,
886 pgoff_t index, struct file *file)
888 return read_cache_page(mapping, index, NULL, file);
891 static inline struct folio *read_mapping_folio(struct address_space *mapping,
892 pgoff_t index, struct file *file)
894 return read_cache_folio(mapping, index, NULL, file);
898 * Get the offset in PAGE_SIZE (even for hugetlb pages).
900 static inline pgoff_t page_to_pgoff(struct page *page)
904 if (likely(!PageTransTail(page)))
907 head = compound_head(page);
909 * We don't initialize ->index for tail pages: calculate based on
912 return head->index + page - head;
916 * Return byte-offset into filesystem object for page.
918 static inline loff_t page_offset(struct page *page)
920 return ((loff_t)page->index) << PAGE_SHIFT;
923 static inline loff_t page_file_offset(struct page *page)
925 return ((loff_t)page_index(page)) << PAGE_SHIFT;
929 * folio_pos - Returns the byte position of this folio in its file.
932 static inline loff_t folio_pos(struct folio *folio)
934 return page_offset(&folio->page);
938 * folio_file_pos - Returns the byte position of this folio in its file.
941 * This differs from folio_pos() for folios which belong to a swap file.
942 * NFS is the only filesystem today which needs to use folio_file_pos().
944 static inline loff_t folio_file_pos(struct folio *folio)
946 return page_file_offset(&folio->page);
950 * Get the offset in PAGE_SIZE (even for hugetlb folios).
952 static inline pgoff_t folio_pgoff(struct folio *folio)
957 static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
958 unsigned long address)
961 pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
962 pgoff += vma->vm_pgoff;
966 struct wait_page_key {
972 struct wait_page_queue {
975 wait_queue_entry_t wait;
978 static inline bool wake_page_match(struct wait_page_queue *wait_page,
979 struct wait_page_key *key)
981 if (wait_page->folio != key->folio)
985 if (wait_page->bit_nr != key->bit_nr)
991 void __folio_lock(struct folio *folio);
992 int __folio_lock_killable(struct folio *folio);
993 vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf);
994 void unlock_page(struct page *page);
995 void folio_unlock(struct folio *folio);
998 * folio_trylock() - Attempt to lock a folio.
999 * @folio: The folio to attempt to lock.
1001 * Sometimes it is undesirable to wait for a folio to be unlocked (eg
1002 * when the locks are being taken in the wrong order, or if making
1003 * progress through a batch of folios is more important than processing
1004 * them in order). Usually folio_lock() is the correct function to call.
1006 * Context: Any context.
1007 * Return: Whether the lock was successfully acquired.
1009 static inline bool folio_trylock(struct folio *folio)
1011 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
1015 * Return true if the page was successfully locked
1017 static inline int trylock_page(struct page *page)
1019 return folio_trylock(page_folio(page));
1023 * folio_lock() - Lock this folio.
1024 * @folio: The folio to lock.
1026 * The folio lock protects against many things, probably more than it
1027 * should. It is primarily held while a folio is being brought uptodate,
1028 * either from its backing file or from swap. It is also held while a
1029 * folio is being truncated from its address_space, so holding the lock
1030 * is sufficient to keep folio->mapping stable.
1032 * The folio lock is also held while write() is modifying the page to
1033 * provide POSIX atomicity guarantees (as long as the write does not
1034 * cross a page boundary). Other modifications to the data in the folio
1035 * do not hold the folio lock and can race with writes, eg DMA and stores
1038 * Context: May sleep. If you need to acquire the locks of two or
1039 * more folios, they must be in order of ascending index, if they are
1040 * in the same address_space. If they are in different address_spaces,
1041 * acquire the lock of the folio which belongs to the address_space which
1042 * has the lowest address in memory first.
1044 static inline void folio_lock(struct folio *folio)
1047 if (!folio_trylock(folio))
1048 __folio_lock(folio);
1052 * lock_page() - Lock the folio containing this page.
1053 * @page: The page to lock.
1055 * See folio_lock() for a description of what the lock protects.
1056 * This is a legacy function and new code should probably use folio_lock()
1059 * Context: May sleep. Pages in the same folio share a lock, so do not
1060 * attempt to lock two pages which share a folio.
1062 static inline void lock_page(struct page *page)
1064 struct folio *folio;
1067 folio = page_folio(page);
1068 if (!folio_trylock(folio))
1069 __folio_lock(folio);
1073 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
1074 * @folio: The folio to lock.
1076 * Attempts to lock the folio, like folio_lock(), except that the sleep
1077 * to acquire the lock is interruptible by a fatal signal.
1079 * Context: May sleep; see folio_lock().
1080 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
1082 static inline int folio_lock_killable(struct folio *folio)
1085 if (!folio_trylock(folio))
1086 return __folio_lock_killable(folio);
1091 * folio_lock_or_retry - Lock the folio, unless this would block and the
1092 * caller indicated that it can handle a retry.
1094 * Return value and mmap_lock implications depend on flags; see
1095 * __folio_lock_or_retry().
1097 static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
1098 struct vm_fault *vmf)
1101 if (!folio_trylock(folio))
1102 return __folio_lock_or_retry(folio, vmf);
1107 * This is exported only for folio_wait_locked/folio_wait_writeback, etc.,
1108 * and should not be used directly.
1110 void folio_wait_bit(struct folio *folio, int bit_nr);
1111 int folio_wait_bit_killable(struct folio *folio, int bit_nr);
1114 * Wait for a folio to be unlocked.
1116 * This must be called with the caller "holding" the folio,
1117 * ie with increased folio reference count so that the folio won't
1118 * go away during the wait.
1120 static inline void folio_wait_locked(struct folio *folio)
1122 if (folio_test_locked(folio))
1123 folio_wait_bit(folio, PG_locked);
1126 static inline int folio_wait_locked_killable(struct folio *folio)
1128 if (!folio_test_locked(folio))
1130 return folio_wait_bit_killable(folio, PG_locked);
1133 static inline void wait_on_page_locked(struct page *page)
1135 folio_wait_locked(page_folio(page));
1138 void folio_end_read(struct folio *folio, bool success);
1139 void wait_on_page_writeback(struct page *page);
1140 void folio_wait_writeback(struct folio *folio);
1141 int folio_wait_writeback_killable(struct folio *folio);
1142 void end_page_writeback(struct page *page);
1143 void folio_end_writeback(struct folio *folio);
1144 void wait_for_stable_page(struct page *page);
1145 void folio_wait_stable(struct folio *folio);
1146 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
1147 static inline void __set_page_dirty(struct page *page,
1148 struct address_space *mapping, int warn)
1150 __folio_mark_dirty(page_folio(page), mapping, warn);
1152 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
1153 void __folio_cancel_dirty(struct folio *folio);
1154 static inline void folio_cancel_dirty(struct folio *folio)
1156 /* Avoid atomic ops, locking, etc. when not actually needed. */
1157 if (folio_test_dirty(folio))
1158 __folio_cancel_dirty(folio);
1160 bool folio_clear_dirty_for_io(struct folio *folio);
1161 bool clear_page_dirty_for_io(struct page *page);
1162 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
1163 int __set_page_dirty_nobuffers(struct page *page);
1164 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
1166 #ifdef CONFIG_MIGRATION
1167 int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
1168 struct folio *src, enum migrate_mode mode);
1170 #define filemap_migrate_folio NULL
1172 void folio_end_private_2(struct folio *folio);
1173 void folio_wait_private_2(struct folio *folio);
1174 int folio_wait_private_2_killable(struct folio *folio);
1177 * Add an arbitrary waiter to a page's wait queue
1179 void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter);
1182 * Fault in userspace address range.
1184 size_t fault_in_writeable(char __user *uaddr, size_t size);
1185 size_t fault_in_subpage_writeable(char __user *uaddr, size_t size);
1186 size_t fault_in_safe_writeable(const char __user *uaddr, size_t size);
1187 size_t fault_in_readable(const char __user *uaddr, size_t size);
1189 int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
1190 pgoff_t index, gfp_t gfp);
1191 int filemap_add_folio(struct address_space *mapping, struct folio *folio,
1192 pgoff_t index, gfp_t gfp);
1193 void filemap_remove_folio(struct folio *folio);
1194 void __filemap_remove_folio(struct folio *folio, void *shadow);
1195 void replace_page_cache_folio(struct folio *old, struct folio *new);
1196 void delete_from_page_cache_batch(struct address_space *mapping,
1197 struct folio_batch *fbatch);
1198 bool filemap_release_folio(struct folio *folio, gfp_t gfp);
1199 loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end,
1202 /* Must be non-static for BPF error injection */
1203 int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
1204 pgoff_t index, gfp_t gfp, void **shadowp);
1206 bool filemap_range_has_writeback(struct address_space *mapping,
1207 loff_t start_byte, loff_t end_byte);
1210 * filemap_range_needs_writeback - check if range potentially needs writeback
1211 * @mapping: address space within which to check
1212 * @start_byte: offset in bytes where the range starts
1213 * @end_byte: offset in bytes where the range ends (inclusive)
1215 * Find at least one page in the range supplied, usually used to check if
1216 * direct writing in this range will trigger a writeback. Used by O_DIRECT
1217 * read/write with IOCB_NOWAIT, to see if the caller needs to do
1218 * filemap_write_and_wait_range() before proceeding.
1220 * Return: %true if the caller should do filemap_write_and_wait_range() before
1221 * doing O_DIRECT to a page in this range, %false otherwise.
1223 static inline bool filemap_range_needs_writeback(struct address_space *mapping,
1227 if (!mapping->nrpages)
1229 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
1230 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
1232 return filemap_range_has_writeback(mapping, start_byte, end_byte);
1236 * struct readahead_control - Describes a readahead request.
1238 * A readahead request is for consecutive pages. Filesystems which
1239 * implement the ->readahead method should call readahead_page() or
1240 * readahead_page_batch() in a loop and attempt to start I/O against
1241 * each page in the request.
1243 * Most of the fields in this struct are private and should be accessed
1244 * by the functions below.
1246 * @file: The file, used primarily by network filesystems for authentication.
1247 * May be NULL if invoked internally by the filesystem.
1248 * @mapping: Readahead this filesystem object.
1249 * @ra: File readahead state. May be NULL.
1251 struct readahead_control {
1253 struct address_space *mapping;
1254 struct file_ra_state *ra;
1255 /* private: use the readahead_* accessors instead */
1257 unsigned int _nr_pages;
1258 unsigned int _batch_count;
1260 unsigned long _pflags;
1263 #define DEFINE_READAHEAD(ractl, f, r, m, i) \
1264 struct readahead_control ractl = { \
1271 #define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
1273 void page_cache_ra_unbounded(struct readahead_control *,
1274 unsigned long nr_to_read, unsigned long lookahead_count);
1275 void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
1276 void page_cache_async_ra(struct readahead_control *, struct folio *,
1277 unsigned long req_count);
1278 void readahead_expand(struct readahead_control *ractl,
1279 loff_t new_start, size_t new_len);
1282 * page_cache_sync_readahead - generic file readahead
1283 * @mapping: address_space which holds the pagecache and I/O vectors
1284 * @ra: file_ra_state which holds the readahead state
1285 * @file: Used by the filesystem for authentication.
1286 * @index: Index of first page to be read.
1287 * @req_count: Total number of pages being read by the caller.
1289 * page_cache_sync_readahead() should be called when a cache miss happened:
1290 * it will submit the read. The readahead logic may decide to piggyback more
1291 * pages onto the read request if access patterns suggest it will improve
1295 void page_cache_sync_readahead(struct address_space *mapping,
1296 struct file_ra_state *ra, struct file *file, pgoff_t index,
1297 unsigned long req_count)
1299 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1300 page_cache_sync_ra(&ractl, req_count);
1304 * page_cache_async_readahead - file readahead for marked pages
1305 * @mapping: address_space which holds the pagecache and I/O vectors
1306 * @ra: file_ra_state which holds the readahead state
1307 * @file: Used by the filesystem for authentication.
1308 * @folio: The folio at @index which triggered the readahead call.
1309 * @index: Index of first page to be read.
1310 * @req_count: Total number of pages being read by the caller.
1312 * page_cache_async_readahead() should be called when a page is used which
1313 * is marked as PageReadahead; this is a marker to suggest that the application
1314 * has used up enough of the readahead window that we should start pulling in
1318 void page_cache_async_readahead(struct address_space *mapping,
1319 struct file_ra_state *ra, struct file *file,
1320 struct folio *folio, pgoff_t index, unsigned long req_count)
1322 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1323 page_cache_async_ra(&ractl, folio, req_count);
1326 static inline struct folio *__readahead_folio(struct readahead_control *ractl)
1328 struct folio *folio;
1330 BUG_ON(ractl->_batch_count > ractl->_nr_pages);
1331 ractl->_nr_pages -= ractl->_batch_count;
1332 ractl->_index += ractl->_batch_count;
1334 if (!ractl->_nr_pages) {
1335 ractl->_batch_count = 0;
1339 folio = xa_load(&ractl->mapping->i_pages, ractl->_index);
1340 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
1341 ractl->_batch_count = folio_nr_pages(folio);
1347 * readahead_page - Get the next page to read.
1348 * @ractl: The current readahead request.
1350 * Context: The page is locked and has an elevated refcount. The caller
1351 * should decreases the refcount once the page has been submitted for I/O
1352 * and unlock the page once all I/O to that page has completed.
1353 * Return: A pointer to the next page, or %NULL if we are done.
1355 static inline struct page *readahead_page(struct readahead_control *ractl)
1357 struct folio *folio = __readahead_folio(ractl);
1359 return &folio->page;
1363 * readahead_folio - Get the next folio to read.
1364 * @ractl: The current readahead request.
1366 * Context: The folio is locked. The caller should unlock the folio once
1367 * all I/O to that folio has completed.
1368 * Return: A pointer to the next folio, or %NULL if we are done.
1370 static inline struct folio *readahead_folio(struct readahead_control *ractl)
1372 struct folio *folio = __readahead_folio(ractl);
1379 static inline unsigned int __readahead_batch(struct readahead_control *rac,
1380 struct page **array, unsigned int array_sz)
1383 XA_STATE(xas, &rac->mapping->i_pages, 0);
1386 BUG_ON(rac->_batch_count > rac->_nr_pages);
1387 rac->_nr_pages -= rac->_batch_count;
1388 rac->_index += rac->_batch_count;
1389 rac->_batch_count = 0;
1391 xas_set(&xas, rac->_index);
1393 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
1394 if (xas_retry(&xas, page))
1396 VM_BUG_ON_PAGE(!PageLocked(page), page);
1397 VM_BUG_ON_PAGE(PageTail(page), page);
1399 rac->_batch_count += thp_nr_pages(page);
1409 * readahead_page_batch - Get a batch of pages to read.
1410 * @rac: The current readahead request.
1411 * @array: An array of pointers to struct page.
1413 * Context: The pages are locked and have an elevated refcount. The caller
1414 * should decreases the refcount once the page has been submitted for I/O
1415 * and unlock the page once all I/O to that page has completed.
1416 * Return: The number of pages placed in the array. 0 indicates the request
1419 #define readahead_page_batch(rac, array) \
1420 __readahead_batch(rac, array, ARRAY_SIZE(array))
1423 * readahead_pos - The byte offset into the file of this readahead request.
1424 * @rac: The readahead request.
1426 static inline loff_t readahead_pos(struct readahead_control *rac)
1428 return (loff_t)rac->_index * PAGE_SIZE;
1432 * readahead_length - The number of bytes in this readahead request.
1433 * @rac: The readahead request.
1435 static inline size_t readahead_length(struct readahead_control *rac)
1437 return rac->_nr_pages * PAGE_SIZE;
1441 * readahead_index - The index of the first page in this readahead request.
1442 * @rac: The readahead request.
1444 static inline pgoff_t readahead_index(struct readahead_control *rac)
1450 * readahead_count - The number of pages in this readahead request.
1451 * @rac: The readahead request.
1453 static inline unsigned int readahead_count(struct readahead_control *rac)
1455 return rac->_nr_pages;
1459 * readahead_batch_length - The number of bytes in the current batch.
1460 * @rac: The readahead request.
1462 static inline size_t readahead_batch_length(struct readahead_control *rac)
1464 return rac->_batch_count * PAGE_SIZE;
1467 static inline unsigned long dir_pages(struct inode *inode)
1469 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
1474 * folio_mkwrite_check_truncate - check if folio was truncated
1475 * @folio: the folio to check
1476 * @inode: the inode to check the folio against
1478 * Return: the number of bytes in the folio up to EOF,
1479 * or -EFAULT if the folio was truncated.
1481 static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
1482 struct inode *inode)
1484 loff_t size = i_size_read(inode);
1485 pgoff_t index = size >> PAGE_SHIFT;
1486 size_t offset = offset_in_folio(folio, size);
1488 if (!folio->mapping)
1491 /* folio is wholly inside EOF */
1492 if (folio_next_index(folio) - 1 < index)
1493 return folio_size(folio);
1494 /* folio is wholly past EOF */
1495 if (folio->index > index || !offset)
1497 /* folio is partially inside EOF */
1502 * page_mkwrite_check_truncate - check if page was truncated
1503 * @page: the page to check
1504 * @inode: the inode to check the page against
1506 * Returns the number of bytes in the page up to EOF,
1507 * or -EFAULT if the page was truncated.
1509 static inline int page_mkwrite_check_truncate(struct page *page,
1510 struct inode *inode)
1512 loff_t size = i_size_read(inode);
1513 pgoff_t index = size >> PAGE_SHIFT;
1514 int offset = offset_in_page(size);
1516 if (page->mapping != inode->i_mapping)
1519 /* page is wholly inside EOF */
1520 if (page->index < index)
1522 /* page is wholly past EOF */
1523 if (page->index > index || !offset)
1525 /* page is partially inside EOF */
1530 * i_blocks_per_folio - How many blocks fit in this folio.
1531 * @inode: The inode which contains the blocks.
1532 * @folio: The folio.
1534 * If the block size is larger than the size of this folio, return zero.
1536 * Context: The caller should hold a refcount on the folio to prevent it
1538 * Return: The number of filesystem blocks covered by this folio.
1541 unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
1543 return folio_size(folio) >> inode->i_blkbits;
1547 unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
1549 return i_blocks_per_folio(inode, page_folio(page));
1551 #endif /* _LINUX_PAGEMAP_H */