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 19struct folio_batch; 20 21unsigned long invalidate_mapping_pages(struct address_space *mapping, 22 pgoff_t start, pgoff_t end); 23 24static 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} 30int invalidate_inode_pages2(struct address_space *mapping); 31int invalidate_inode_pages2_range(struct address_space *mapping, 32 pgoff_t start, pgoff_t end); 33int kiocb_invalidate_pages(struct kiocb *iocb, size_t count); 34void kiocb_invalidate_post_direct_write(struct kiocb *iocb, size_t count); 35 36int write_inode_now(struct inode *, int sync); 37int filemap_fdatawrite(struct address_space *); 38int filemap_flush(struct address_space *); 39int filemap_fdatawait_keep_errors(struct address_space *mapping); 40int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend); 41int filemap_fdatawait_range_keep_errors(struct address_space *mapping, 42 loff_t start_byte, loff_t end_byte); 43 44static inline int filemap_fdatawait(struct address_space *mapping) 45{ 46 return filemap_fdatawait_range(mapping, 0, LLONG_MAX); 47} 48 49bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend); 50int filemap_write_and_wait_range(struct address_space *mapping, 51 loff_t lstart, loff_t lend); 52int __filemap_fdatawrite_range(struct address_space *mapping, 53 loff_t start, loff_t end, int sync_mode); 54int filemap_fdatawrite_range(struct address_space *mapping, 55 loff_t start, loff_t end); 56int filemap_check_errors(struct address_space *mapping); 57void __filemap_set_wb_err(struct address_space *mapping, int err); 58int filemap_fdatawrite_wbc(struct address_space *mapping, 59 struct writeback_control *wbc); 60int kiocb_write_and_wait(struct kiocb *iocb, size_t count); 61 62static 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 */ 81static 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 */ 98static 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 */ 111static 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 */ 123static 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 */ 133static 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 139static 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 */ 165static 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 */ 197enum 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 AS_UNMOVABLE, /* The mapping cannot be moved, ever */ 210}; 211 212/** 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 216 * 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. 221 * 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). 225 */ 226static inline void mapping_set_error(struct address_space *mapping, int error) 227{ 228 if (likely(!error)) 229 return; 230 231 /* Record in wb_err for checkers using errseq_t based tracking */ 232 __filemap_set_wb_err(mapping, error); 233 234 /* Record it in superblock */ 235 if (mapping->host) 236 errseq_set(&mapping->host->i_sb->s_wb_err, error); 237 238 /* Record it in flags for now, for legacy callers */ 239 if (error == -ENOSPC) 240 set_bit(AS_ENOSPC, &mapping->flags); 241 else 242 set_bit(AS_EIO, &mapping->flags); 243} 244 245static inline void mapping_set_unevictable(struct address_space *mapping) 246{ 247 set_bit(AS_UNEVICTABLE, &mapping->flags); 248} 249 250static inline void mapping_clear_unevictable(struct address_space *mapping) 251{ 252 clear_bit(AS_UNEVICTABLE, &mapping->flags); 253} 254 255static inline bool mapping_unevictable(struct address_space *mapping) 256{ 257 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags); 258} 259 260static inline void mapping_set_exiting(struct address_space *mapping) 261{ 262 set_bit(AS_EXITING, &mapping->flags); 263} 264 265static inline int mapping_exiting(struct address_space *mapping) 266{ 267 return test_bit(AS_EXITING, &mapping->flags); 268} 269 270static inline void mapping_set_no_writeback_tags(struct address_space *mapping) 271{ 272 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 273} 274 275static inline int mapping_use_writeback_tags(struct address_space *mapping) 276{ 277 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 278} 279 280static inline bool mapping_release_always(const struct address_space *mapping) 281{ 282 return test_bit(AS_RELEASE_ALWAYS, &mapping->flags); 283} 284 285static inline void mapping_set_release_always(struct address_space *mapping) 286{ 287 set_bit(AS_RELEASE_ALWAYS, &mapping->flags); 288} 289 290static inline void mapping_clear_release_always(struct address_space *mapping) 291{ 292 clear_bit(AS_RELEASE_ALWAYS, &mapping->flags); 293} 294 295static inline bool mapping_stable_writes(const struct address_space *mapping) 296{ 297 return test_bit(AS_STABLE_WRITES, &mapping->flags); 298} 299 300static inline void mapping_set_stable_writes(struct address_space *mapping) 301{ 302 set_bit(AS_STABLE_WRITES, &mapping->flags); 303} 304 305static inline void mapping_clear_stable_writes(struct address_space *mapping) 306{ 307 clear_bit(AS_STABLE_WRITES, &mapping->flags); 308} 309 310static inline void mapping_set_unmovable(struct address_space *mapping) 311{ 312 /* 313 * It's expected unmovable mappings are also unevictable. Compaction 314 * migrate scanner (isolate_migratepages_block()) relies on this to 315 * reduce page locking. 316 */ 317 set_bit(AS_UNEVICTABLE, &mapping->flags); 318 set_bit(AS_UNMOVABLE, &mapping->flags); 319} 320 321static inline bool mapping_unmovable(struct address_space *mapping) 322{ 323 return test_bit(AS_UNMOVABLE, &mapping->flags); 324} 325 326static inline gfp_t mapping_gfp_mask(struct address_space * mapping) 327{ 328 return mapping->gfp_mask; 329} 330 331/* Restricts the given gfp_mask to what the mapping allows. */ 332static inline gfp_t mapping_gfp_constraint(struct address_space *mapping, 333 gfp_t gfp_mask) 334{ 335 return mapping_gfp_mask(mapping) & gfp_mask; 336} 337 338/* 339 * This is non-atomic. Only to be used before the mapping is activated. 340 * Probably needs a barrier... 341 */ 342static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) 343{ 344 m->gfp_mask = mask; 345} 346 347/** 348 * mapping_set_large_folios() - Indicate the file supports large folios. 349 * @mapping: The file. 350 * 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 353 * the file. 354 * 355 * Context: This should not be called while the inode is active as it 356 * is non-atomic. 357 */ 358static inline void mapping_set_large_folios(struct address_space *mapping) 359{ 360 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); 361} 362 363/* 364 * Large folio support currently depends on THP. These dependencies are 365 * being worked on but are not yet fixed. 366 */ 367static inline bool mapping_large_folio_support(struct address_space *mapping) 368{ 369 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && 370 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); 371} 372 373static inline int filemap_nr_thps(struct address_space *mapping) 374{ 375#ifdef CONFIG_READ_ONLY_THP_FOR_FS 376 return atomic_read(&mapping->nr_thps); 377#else 378 return 0; 379#endif 380} 381 382static inline void filemap_nr_thps_inc(struct address_space *mapping) 383{ 384#ifdef CONFIG_READ_ONLY_THP_FOR_FS 385 if (!mapping_large_folio_support(mapping)) 386 atomic_inc(&mapping->nr_thps); 387#else 388 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); 389#endif 390} 391 392static inline void filemap_nr_thps_dec(struct address_space *mapping) 393{ 394#ifdef CONFIG_READ_ONLY_THP_FOR_FS 395 if (!mapping_large_folio_support(mapping)) 396 atomic_dec(&mapping->nr_thps); 397#else 398 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); 399#endif 400} 401 402struct address_space *page_mapping(struct page *); 403struct address_space *folio_mapping(struct folio *); 404struct address_space *swapcache_mapping(struct folio *); 405 406/** 407 * folio_file_mapping - Find the mapping this folio belongs to. 408 * @folio: The folio. 409 * 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. 415 * 416 * Do not call this for folios which aren't in the page cache or swap cache. 417 */ 418static inline struct address_space *folio_file_mapping(struct folio *folio) 419{ 420 if (unlikely(folio_test_swapcache(folio))) 421 return swapcache_mapping(folio); 422 423 return folio->mapping; 424} 425 426/** 427 * folio_flush_mapping - Find the file mapping this folio belongs to. 428 * @folio: The folio. 429 * 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. 433 * 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(). 437 */ 438static inline struct address_space *folio_flush_mapping(struct folio *folio) 439{ 440 if (unlikely(folio_test_swapcache(folio))) 441 return NULL; 442 443 return folio_mapping(folio); 444} 445 446static inline struct address_space *page_file_mapping(struct page *page) 447{ 448 return folio_file_mapping(page_folio(page)); 449} 450 451/** 452 * folio_inode - Get the host inode for this folio. 453 * @folio: The folio. 454 * 455 * For folios which are in the page cache, return the inode that this folio 456 * belongs to. 457 * 458 * Do not call this for folios which aren't in the page cache. 459 */ 460static inline struct inode *folio_inode(struct folio *folio) 461{ 462 return folio->mapping->host; 463} 464 465/** 466 * folio_attach_private - Attach private data to a folio. 467 * @folio: Folio to attach data to. 468 * @data: Data to attach to folio. 469 * 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. 472 */ 473static inline void folio_attach_private(struct folio *folio, void *data) 474{ 475 folio_get(folio); 476 folio->private = data; 477 folio_set_private(folio); 478} 479 480/** 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. 484 * 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. 488 * 489 * Return: Data that was previously attached to the folio. 490 */ 491static inline void *folio_change_private(struct folio *folio, void *data) 492{ 493 void *old = folio_get_private(folio); 494 495 folio->private = data; 496 return old; 497} 498 499/** 500 * folio_detach_private - Detach private data from a folio. 501 * @folio: Folio to detach data from. 502 * 503 * Removes the data that was previously attached to the folio and decrements 504 * the refcount on the page. 505 * 506 * Return: Data that was attached to the folio. 507 */ 508static inline void *folio_detach_private(struct folio *folio) 509{ 510 void *data = folio_get_private(folio); 511 512 if (!folio_test_private(folio)) 513 return NULL; 514 folio_clear_private(folio); 515 folio->private = NULL; 516 folio_put(folio); 517 518 return data; 519} 520 521static inline void attach_page_private(struct page *page, void *data) 522{ 523 folio_attach_private(page_folio(page), data); 524} 525 526static inline void *detach_page_private(struct page *page) 527{ 528 return folio_detach_private(page_folio(page)); 529} 530 531/* 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) 537 */ 538#ifdef CONFIG_TRANSPARENT_HUGEPAGE 539#define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER 540#else 541#define MAX_PAGECACHE_ORDER 8 542#endif 543 544#ifdef CONFIG_NUMA 545struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order); 546#else 547static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order) 548{ 549 return folio_alloc(gfp, order); 550} 551#endif 552 553static inline struct page *__page_cache_alloc(gfp_t gfp) 554{ 555 return &filemap_alloc_folio(gfp, 0)->page; 556} 557 558static inline struct page *page_cache_alloc(struct address_space *x) 559{ 560 return __page_cache_alloc(mapping_gfp_mask(x)); 561} 562 563static inline gfp_t readahead_gfp_mask(struct address_space *x) 564{ 565 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN; 566} 567 568typedef int filler_t(struct file *, struct folio *); 569 570pgoff_t page_cache_next_miss(struct address_space *mapping, 571 pgoff_t index, unsigned long max_scan); 572pgoff_t page_cache_prev_miss(struct address_space *mapping, 573 pgoff_t index, unsigned long max_scan); 574 575/** 576 * typedef fgf_t - Flags for getting folios from the page cache. 577 * 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() 582 * are available. 583 * 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 588 * returned locked. 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() 597 * implementation. 598 */ 599typedef unsigned int __bitwise fgf_t; 600 601#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 */ 610 611#define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE) 612 613/** 614 * fgf_set_order - Encode a length in the fgf_t flags. 615 * @size: The suggested size of the folio to create. 616 * 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. 623 */ 624static inline fgf_t fgf_set_order(size_t size) 625{ 626 unsigned int shift = ilog2(size); 627 628 if (shift <= PAGE_SHIFT) 629 return 0; 630 return (__force fgf_t)((shift - PAGE_SHIFT) << 26); 631} 632 633void *filemap_get_entry(struct address_space *mapping, pgoff_t index); 634struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, 635 fgf_t fgp_flags, gfp_t gfp); 636struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, 637 fgf_t fgp_flags, gfp_t gfp); 638 639/** 640 * filemap_get_folio - Find and get a folio. 641 * @mapping: The address_space to search. 642 * @index: The page index. 643 * 644 * Looks up the page cache entry at @mapping & @index. If a folio is 645 * present, it is returned with an increased refcount. 646 * 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. 649 */ 650static inline struct folio *filemap_get_folio(struct address_space *mapping, 651 pgoff_t index) 652{ 653 return __filemap_get_folio(mapping, index, 0, 0); 654} 655 656/** 657 * filemap_lock_folio - Find and lock a folio. 658 * @mapping: The address_space to search. 659 * @index: The page index. 660 * 661 * Looks up the page cache entry at @mapping & @index. If a folio is 662 * present, it is returned locked with an increased refcount. 663 * 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. 667 */ 668static inline struct folio *filemap_lock_folio(struct address_space *mapping, 669 pgoff_t index) 670{ 671 return __filemap_get_folio(mapping, index, FGP_LOCK, 0); 672} 673 674/** 675 * filemap_grab_folio - grab a folio from the page cache 676 * @mapping: The address space to search 677 * @index: The page index 678 * 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 681 * returned. 682 * 683 * Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found 684 * and failed to create a folio. 685 */ 686static inline struct folio *filemap_grab_folio(struct address_space *mapping, 687 pgoff_t index) 688{ 689 return __filemap_get_folio(mapping, index, 690 FGP_LOCK | FGP_ACCESSED | FGP_CREAT, 691 mapping_gfp_mask(mapping)); 692} 693 694/** 695 * find_get_page - find and get a page reference 696 * @mapping: the address_space to search 697 * @offset: the page index 698 * 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. 701 * 702 * Otherwise, %NULL is returned. 703 */ 704static inline struct page *find_get_page(struct address_space *mapping, 705 pgoff_t offset) 706{ 707 return pagecache_get_page(mapping, offset, 0, 0); 708} 709 710static inline struct page *find_get_page_flags(struct address_space *mapping, 711 pgoff_t offset, fgf_t fgp_flags) 712{ 713 return pagecache_get_page(mapping, offset, fgp_flags, 0); 714} 715 716/** 717 * find_lock_page - locate, pin and lock a pagecache page 718 * @mapping: the address_space to search 719 * @index: the page index 720 * 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 723 * refcount. 724 * 725 * Context: May sleep. 726 * Return: A struct page or %NULL if there is no page in the cache for this 727 * index. 728 */ 729static inline struct page *find_lock_page(struct address_space *mapping, 730 pgoff_t index) 731{ 732 return pagecache_get_page(mapping, index, FGP_LOCK, 0); 733} 734 735/** 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 740 * 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 743 * refcount. 744 * 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. 748 * 749 * On memory exhaustion, %NULL is returned. 750 * 751 * find_or_create_page() may sleep, even if @gfp_flags specifies an 752 * atomic allocation! 753 */ 754static inline struct page *find_or_create_page(struct address_space *mapping, 755 pgoff_t index, gfp_t gfp_mask) 756{ 757 return pagecache_get_page(mapping, index, 758 FGP_LOCK|FGP_ACCESSED|FGP_CREAT, 759 gfp_mask); 760} 761 762/** 763 * grab_cache_page_nowait - returns locked page at given index in given cache 764 * @mapping: target address_space 765 * @index: the page index 766 * 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. 771 * 772 * Clear __GFP_FS when allocating the page to avoid recursion into the fs 773 * and deadlock against the caller's locked page. 774 */ 775static inline struct page *grab_cache_page_nowait(struct address_space *mapping, 776 pgoff_t index) 777{ 778 return pagecache_get_page(mapping, index, 779 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT, 780 mapping_gfp_mask(mapping)); 781} 782 783#define swapcache_index(folio) __page_file_index(&(folio)->page) 784 785/** 786 * folio_index - File index of a folio. 787 * @folio: The folio. 788 * 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 792 * index directly. 793 * 794 * Return: The index (offset in units of pages) of a folio in its file. 795 */ 796static inline pgoff_t folio_index(struct folio *folio) 797{ 798 if (unlikely(folio_test_swapcache(folio))) 799 return swapcache_index(folio); 800 return folio->index; 801} 802 803/** 804 * folio_next_index - Get the index of the next folio. 805 * @folio: The current folio. 806 * 807 * Return: The index of the folio which follows this folio in the file. 808 */ 809static inline pgoff_t folio_next_index(struct folio *folio) 810{ 811 return folio->index + folio_nr_pages(folio); 812} 813 814/** 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. 818 * 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). 821 * 822 * Return: The page containing the file data for this index. 823 */ 824static inline struct page *folio_file_page(struct folio *folio, pgoff_t index) 825{ 826 return folio_page(folio, index & (folio_nr_pages(folio) - 1)); 827} 828 829/** 830 * folio_contains - Does this folio contain this index? 831 * @folio: The folio. 832 * @index: The page index within the file. 833 * 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. 838 */ 839static inline bool folio_contains(struct folio *folio, pgoff_t index) 840{ 841 return index - folio_index(folio) < folio_nr_pages(folio); 842} 843 844/* 845 * Given the page we found in the page cache, return the page corresponding 846 * to this index in the file 847 */ 848static inline struct page *find_subpage(struct page *head, pgoff_t index) 849{ 850 /* HugeTLBfs wants the head page regardless */ 851 if (PageHuge(head)) 852 return head; 853 854 return head + (index & (thp_nr_pages(head) - 1)); 855} 856 857unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start, 858 pgoff_t end, struct folio_batch *fbatch); 859unsigned filemap_get_folios_contig(struct address_space *mapping, 860 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch); 861unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start, 862 pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch); 863 864struct page *grab_cache_page_write_begin(struct address_space *mapping, 865 pgoff_t index); 866 867/* 868 * Returns locked page at given index in given cache, creating it if needed. 869 */ 870static inline struct page *grab_cache_page(struct address_space *mapping, 871 pgoff_t index) 872{ 873 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping)); 874} 875 876struct folio *read_cache_folio(struct address_space *, pgoff_t index, 877 filler_t *filler, struct file *file); 878struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index, 879 gfp_t flags); 880struct page *read_cache_page(struct address_space *, pgoff_t index, 881 filler_t *filler, struct file *file); 882extern struct page * read_cache_page_gfp(struct address_space *mapping, 883 pgoff_t index, gfp_t gfp_mask); 884 885static inline struct page *read_mapping_page(struct address_space *mapping, 886 pgoff_t index, struct file *file) 887{ 888 return read_cache_page(mapping, index, NULL, file); 889} 890 891static inline struct folio *read_mapping_folio(struct address_space *mapping, 892 pgoff_t index, struct file *file) 893{ 894 return read_cache_folio(mapping, index, NULL, file); 895} 896 897/* 898 * Get the offset in PAGE_SIZE (even for hugetlb pages). 899 */ 900static inline pgoff_t page_to_pgoff(struct page *page) 901{ 902 struct page *head; 903 904 if (likely(!PageTransTail(page))) 905 return page->index; 906 907 head = compound_head(page); 908 /* 909 * We don't initialize ->index for tail pages: calculate based on 910 * head page 911 */ 912 return head->index + page - head; 913} 914 915/* 916 * Return byte-offset into filesystem object for page. 917 */ 918static inline loff_t page_offset(struct page *page) 919{ 920 return ((loff_t)page->index) << PAGE_SHIFT; 921} 922 923static inline loff_t page_file_offset(struct page *page) 924{ 925 return ((loff_t)page_index(page)) << PAGE_SHIFT; 926} 927 928/** 929 * folio_pos - Returns the byte position of this folio in its file. 930 * @folio: The folio. 931 */ 932static inline loff_t folio_pos(struct folio *folio) 933{ 934 return page_offset(&folio->page); 935} 936 937/** 938 * folio_file_pos - Returns the byte position of this folio in its file. 939 * @folio: The folio. 940 * 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(). 943 */ 944static inline loff_t folio_file_pos(struct folio *folio) 945{ 946 return page_file_offset(&folio->page); 947} 948 949/* 950 * Get the offset in PAGE_SIZE (even for hugetlb folios). 951 */ 952static inline pgoff_t folio_pgoff(struct folio *folio) 953{ 954 return folio->index; 955} 956 957static inline pgoff_t linear_page_index(struct vm_area_struct *vma, 958 unsigned long address) 959{ 960 pgoff_t pgoff; 961 pgoff = (address - vma->vm_start) >> PAGE_SHIFT; 962 pgoff += vma->vm_pgoff; 963 return pgoff; 964} 965 966struct wait_page_key { 967 struct folio *folio; 968 int bit_nr; 969 int page_match; 970}; 971 972struct wait_page_queue { 973 struct folio *folio; 974 int bit_nr; 975 wait_queue_entry_t wait; 976}; 977 978static inline bool wake_page_match(struct wait_page_queue *wait_page, 979 struct wait_page_key *key) 980{ 981 if (wait_page->folio != key->folio) 982 return false; 983 key->page_match = 1; 984 985 if (wait_page->bit_nr != key->bit_nr) 986 return false; 987 988 return true; 989} 990 991void __folio_lock(struct folio *folio); 992int __folio_lock_killable(struct folio *folio); 993vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf); 994void unlock_page(struct page *page); 995void folio_unlock(struct folio *folio); 996 997/** 998 * folio_trylock() - Attempt to lock a folio. 999 * @folio: The folio to attempt to lock. 1000 * 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. 1005 * 1006 * Context: Any context. 1007 * Return: Whether the lock was successfully acquired. 1008 */ 1009static inline bool folio_trylock(struct folio *folio) 1010{ 1011 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0))); 1012} 1013 1014/* 1015 * Return true if the page was successfully locked 1016 */ 1017static inline int trylock_page(struct page *page) 1018{ 1019 return folio_trylock(page_folio(page)); 1020} 1021 1022/** 1023 * folio_lock() - Lock this folio. 1024 * @folio: The folio to lock. 1025 * 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. 1031 * 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 1036 * to mapped pages. 1037 * 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. 1043 */ 1044static inline void folio_lock(struct folio *folio) 1045{ 1046 might_sleep(); 1047 if (!folio_trylock(folio)) 1048 __folio_lock(folio); 1049} 1050 1051/** 1052 * lock_page() - Lock the folio containing this page. 1053 * @page: The page to lock. 1054 * 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() 1057 * instead. 1058 * 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. 1061 */ 1062static inline void lock_page(struct page *page) 1063{ 1064 struct folio *folio; 1065 might_sleep(); 1066 1067 folio = page_folio(page); 1068 if (!folio_trylock(folio)) 1069 __folio_lock(folio); 1070} 1071 1072/** 1073 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal. 1074 * @folio: The folio to lock. 1075 * 1076 * Attempts to lock the folio, like folio_lock(), except that the sleep 1077 * to acquire the lock is interruptible by a fatal signal. 1078 * 1079 * Context: May sleep; see folio_lock(). 1080 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received. 1081 */ 1082static inline int folio_lock_killable(struct folio *folio) 1083{ 1084 might_sleep(); 1085 if (!folio_trylock(folio)) 1086 return __folio_lock_killable(folio); 1087 return 0; 1088} 1089 1090/* 1091 * folio_lock_or_retry - Lock the folio, unless this would block and the 1092 * caller indicated that it can handle a retry. 1093 * 1094 * Return value and mmap_lock implications depend on flags; see 1095 * __folio_lock_or_retry(). 1096 */ 1097static inline vm_fault_t folio_lock_or_retry(struct folio *folio, 1098 struct vm_fault *vmf) 1099{ 1100 might_sleep(); 1101 if (!folio_trylock(folio)) 1102 return __folio_lock_or_retry(folio, vmf); 1103 return 0; 1104} 1105 1106/* 1107 * This is exported only for folio_wait_locked/folio_wait_writeback, etc., 1108 * and should not be used directly. 1109 */ 1110void folio_wait_bit(struct folio *folio, int bit_nr); 1111int folio_wait_bit_killable(struct folio *folio, int bit_nr); 1112 1113/* 1114 * Wait for a folio to be unlocked. 1115 * 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. 1119 */ 1120static inline void folio_wait_locked(struct folio *folio) 1121{ 1122 if (folio_test_locked(folio)) 1123 folio_wait_bit(folio, PG_locked); 1124} 1125 1126static inline int folio_wait_locked_killable(struct folio *folio) 1127{ 1128 if (!folio_test_locked(folio)) 1129 return 0; 1130 return folio_wait_bit_killable(folio, PG_locked); 1131} 1132 1133static inline void wait_on_page_locked(struct page *page) 1134{ 1135 folio_wait_locked(page_folio(page)); 1136} 1137 1138void folio_end_read(struct folio *folio, bool success); 1139void wait_on_page_writeback(struct page *page); 1140void folio_wait_writeback(struct folio *folio); 1141int folio_wait_writeback_killable(struct folio *folio); 1142void end_page_writeback(struct page *page); 1143void folio_end_writeback(struct folio *folio); 1144void wait_for_stable_page(struct page *page); 1145void folio_wait_stable(struct folio *folio); 1146void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn); 1147static inline void __set_page_dirty(struct page *page, 1148 struct address_space *mapping, int warn) 1149{ 1150 __folio_mark_dirty(page_folio(page), mapping, warn); 1151} 1152void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb); 1153void __folio_cancel_dirty(struct folio *folio); 1154static inline void folio_cancel_dirty(struct folio *folio) 1155{ 1156 /* Avoid atomic ops, locking, etc. when not actually needed. */ 1157 if (folio_test_dirty(folio)) 1158 __folio_cancel_dirty(folio); 1159} 1160bool folio_clear_dirty_for_io(struct folio *folio); 1161bool clear_page_dirty_for_io(struct page *page); 1162void folio_invalidate(struct folio *folio, size_t offset, size_t length); 1163int __set_page_dirty_nobuffers(struct page *page); 1164bool noop_dirty_folio(struct address_space *mapping, struct folio *folio); 1165 1166#ifdef CONFIG_MIGRATION 1167int filemap_migrate_folio(struct address_space *mapping, struct folio *dst, 1168 struct folio *src, enum migrate_mode mode); 1169#else 1170#define filemap_migrate_folio NULL 1171#endif 1172void folio_end_private_2(struct folio *folio); 1173void folio_wait_private_2(struct folio *folio); 1174int folio_wait_private_2_killable(struct folio *folio); 1175 1176/* 1177 * Add an arbitrary waiter to a page's wait queue 1178 */ 1179void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter); 1180 1181/* 1182 * Fault in userspace address range. 1183 */ 1184size_t fault_in_writeable(char __user *uaddr, size_t size); 1185size_t fault_in_subpage_writeable(char __user *uaddr, size_t size); 1186size_t fault_in_safe_writeable(const char __user *uaddr, size_t size); 1187size_t fault_in_readable(const char __user *uaddr, size_t size); 1188 1189int add_to_page_cache_lru(struct page *page, struct address_space *mapping, 1190 pgoff_t index, gfp_t gfp); 1191int filemap_add_folio(struct address_space *mapping, struct folio *folio, 1192 pgoff_t index, gfp_t gfp); 1193void filemap_remove_folio(struct folio *folio); 1194void __filemap_remove_folio(struct folio *folio, void *shadow); 1195void replace_page_cache_folio(struct folio *old, struct folio *new); 1196void delete_from_page_cache_batch(struct address_space *mapping, 1197 struct folio_batch *fbatch); 1198bool filemap_release_folio(struct folio *folio, gfp_t gfp); 1199loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end, 1200 int whence); 1201 1202/* Must be non-static for BPF error injection */ 1203int __filemap_add_folio(struct address_space *mapping, struct folio *folio, 1204 pgoff_t index, gfp_t gfp, void **shadowp); 1205 1206bool filemap_range_has_writeback(struct address_space *mapping, 1207 loff_t start_byte, loff_t end_byte); 1208 1209/** 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) 1214 * 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. 1219 * 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. 1222 */ 1223static inline bool filemap_range_needs_writeback(struct address_space *mapping, 1224 loff_t start_byte, 1225 loff_t end_byte) 1226{ 1227 if (!mapping->nrpages) 1228 return false; 1229 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && 1230 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) 1231 return false; 1232 return filemap_range_has_writeback(mapping, start_byte, end_byte); 1233} 1234 1235/** 1236 * struct readahead_control - Describes a readahead request. 1237 * 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. 1242 * 1243 * Most of the fields in this struct are private and should be accessed 1244 * by the functions below. 1245 * 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. 1250 */ 1251struct readahead_control { 1252 struct file *file; 1253 struct address_space *mapping; 1254 struct file_ra_state *ra; 1255/* private: use the readahead_* accessors instead */ 1256 pgoff_t _index; 1257 unsigned int _nr_pages; 1258 unsigned int _batch_count; 1259 bool _workingset; 1260 unsigned long _pflags; 1261}; 1262 1263#define DEFINE_READAHEAD(ractl, f, r, m, i) \ 1264 struct readahead_control ractl = { \ 1265 .file = f, \ 1266 .mapping = m, \ 1267 .ra = r, \ 1268 ._index = i, \ 1269 } 1270 1271#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE) 1272 1273void page_cache_ra_unbounded(struct readahead_control *, 1274 unsigned long nr_to_read, unsigned long lookahead_count); 1275void page_cache_sync_ra(struct readahead_control *, unsigned long req_count); 1276void page_cache_async_ra(struct readahead_control *, struct folio *, 1277 unsigned long req_count); 1278void readahead_expand(struct readahead_control *ractl, 1279 loff_t new_start, size_t new_len); 1280 1281/** 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. 1288 * 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 1292 * performance. 1293 */ 1294static inline 1295void 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) 1298{ 1299 DEFINE_READAHEAD(ractl, file, ra, mapping, index); 1300 page_cache_sync_ra(&ractl, req_count); 1301} 1302 1303/** 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. 1311 * 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 1315 * more pages. 1316 */ 1317static inline 1318void 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) 1321{ 1322 DEFINE_READAHEAD(ractl, file, ra, mapping, index); 1323 page_cache_async_ra(&ractl, folio, req_count); 1324} 1325 1326static inline struct folio *__readahead_folio(struct readahead_control *ractl) 1327{ 1328 struct folio *folio; 1329 1330 BUG_ON(ractl->_batch_count > ractl->_nr_pages); 1331 ractl->_nr_pages -= ractl->_batch_count; 1332 ractl->_index += ractl->_batch_count; 1333 1334 if (!ractl->_nr_pages) { 1335 ractl->_batch_count = 0; 1336 return NULL; 1337 } 1338 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); 1342 1343 return folio; 1344} 1345 1346/** 1347 * readahead_page - Get the next page to read. 1348 * @ractl: The current readahead request. 1349 * 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. 1354 */ 1355static inline struct page *readahead_page(struct readahead_control *ractl) 1356{ 1357 struct folio *folio = __readahead_folio(ractl); 1358 1359 return &folio->page; 1360} 1361 1362/** 1363 * readahead_folio - Get the next folio to read. 1364 * @ractl: The current readahead request. 1365 * 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. 1369 */ 1370static inline struct folio *readahead_folio(struct readahead_control *ractl) 1371{ 1372 struct folio *folio = __readahead_folio(ractl); 1373 1374 if (folio) 1375 folio_put(folio); 1376 return folio; 1377} 1378 1379static inline unsigned int __readahead_batch(struct readahead_control *rac, 1380 struct page **array, unsigned int array_sz) 1381{ 1382 unsigned int i = 0; 1383 XA_STATE(xas, &rac->mapping->i_pages, 0); 1384 struct page *page; 1385 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; 1390 1391 xas_set(&xas, rac->_index); 1392 rcu_read_lock(); 1393 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) { 1394 if (xas_retry(&xas, page)) 1395 continue; 1396 VM_BUG_ON_PAGE(!PageLocked(page), page); 1397 VM_BUG_ON_PAGE(PageTail(page), page); 1398 array[i++] = page; 1399 rac->_batch_count += thp_nr_pages(page); 1400 if (i == array_sz) 1401 break; 1402 } 1403 rcu_read_unlock(); 1404 1405 return i; 1406} 1407 1408/** 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. 1412 * 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 1417 * is complete. 1418 */ 1419#define readahead_page_batch(rac, array) \ 1420 __readahead_batch(rac, array, ARRAY_SIZE(array)) 1421 1422/** 1423 * readahead_pos - The byte offset into the file of this readahead request. 1424 * @rac: The readahead request. 1425 */ 1426static inline loff_t readahead_pos(struct readahead_control *rac) 1427{ 1428 return (loff_t)rac->_index * PAGE_SIZE; 1429} 1430 1431/** 1432 * readahead_length - The number of bytes in this readahead request. 1433 * @rac: The readahead request. 1434 */ 1435static inline size_t readahead_length(struct readahead_control *rac) 1436{ 1437 return rac->_nr_pages * PAGE_SIZE; 1438} 1439 1440/** 1441 * readahead_index - The index of the first page in this readahead request. 1442 * @rac: The readahead request. 1443 */ 1444static inline pgoff_t readahead_index(struct readahead_control *rac) 1445{ 1446 return rac->_index; 1447} 1448 1449/** 1450 * readahead_count - The number of pages in this readahead request. 1451 * @rac: The readahead request. 1452 */ 1453static inline unsigned int readahead_count(struct readahead_control *rac) 1454{ 1455 return rac->_nr_pages; 1456} 1457 1458/** 1459 * readahead_batch_length - The number of bytes in the current batch. 1460 * @rac: The readahead request. 1461 */ 1462static inline size_t readahead_batch_length(struct readahead_control *rac) 1463{ 1464 return rac->_batch_count * PAGE_SIZE; 1465} 1466 1467static inline unsigned long dir_pages(struct inode *inode) 1468{ 1469 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >> 1470 PAGE_SHIFT; 1471} 1472 1473/** 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 1477 * 1478 * Return: the number of bytes in the folio up to EOF, 1479 * or -EFAULT if the folio was truncated. 1480 */ 1481static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio, 1482 struct inode *inode) 1483{ 1484 loff_t size = i_size_read(inode); 1485 pgoff_t index = size >> PAGE_SHIFT; 1486 size_t offset = offset_in_folio(folio, size); 1487 1488 if (!folio->mapping) 1489 return -EFAULT; 1490 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) 1496 return -EFAULT; 1497 /* folio is partially inside EOF */ 1498 return offset; 1499} 1500 1501/** 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 1505 * 1506 * Returns the number of bytes in the page up to EOF, 1507 * or -EFAULT if the page was truncated. 1508 */ 1509static inline int page_mkwrite_check_truncate(struct page *page, 1510 struct inode *inode) 1511{ 1512 loff_t size = i_size_read(inode); 1513 pgoff_t index = size >> PAGE_SHIFT; 1514 int offset = offset_in_page(size); 1515 1516 if (page->mapping != inode->i_mapping) 1517 return -EFAULT; 1518 1519 /* page is wholly inside EOF */ 1520 if (page->index < index) 1521 return PAGE_SIZE; 1522 /* page is wholly past EOF */ 1523 if (page->index > index || !offset) 1524 return -EFAULT; 1525 /* page is partially inside EOF */ 1526 return offset; 1527} 1528 1529/** 1530 * i_blocks_per_folio - How many blocks fit in this folio. 1531 * @inode: The inode which contains the blocks. 1532 * @folio: The folio. 1533 * 1534 * If the block size is larger than the size of this folio, return zero. 1535 * 1536 * Context: The caller should hold a refcount on the folio to prevent it 1537 * from being split. 1538 * Return: The number of filesystem blocks covered by this folio. 1539 */ 1540static inline 1541unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio) 1542{ 1543 return folio_size(folio) >> inode->i_blkbits; 1544} 1545 1546static inline 1547unsigned int i_blocks_per_page(struct inode *inode, struct page *page) 1548{ 1549 return i_blocks_per_folio(inode, page_folio(page)); 1550} 1551#endif /* _LINUX_PAGEMAP_H */ 1552