1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_PAGEMAP_H 3 #define _LINUX_PAGEMAP_H 4 5 /* 6 * Copyright 1995 Linus Torvalds 7 */ 8 #include <linux/mm.h> 9 #include <linux/fs.h> 10 #include <linux/list.h> 11 #include <linux/highmem.h> 12 #include <linux/compiler.h> 13 #include <linux/uaccess.h> 14 #include <linux/gfp.h> 15 #include <linux/bitops.h> 16 #include <linux/hardirq.h> /* for in_interrupt() */ 17 #include <linux/hugetlb_inline.h> 18 19 struct folio_batch; 20 21 unsigned long invalidate_mapping_pages(struct address_space *mapping, 22 pgoff_t start, pgoff_t end); 23 24 static inline void invalidate_remote_inode(struct inode *inode) 25 { 26 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || 27 S_ISLNK(inode->i_mode)) 28 invalidate_mapping_pages(inode->i_mapping, 0, -1); 29 } 30 int invalidate_inode_pages2(struct address_space *mapping); 31 int invalidate_inode_pages2_range(struct address_space *mapping, 32 pgoff_t start, pgoff_t end); 33 int write_inode_now(struct inode *, int sync); 34 int filemap_fdatawrite(struct address_space *); 35 int filemap_flush(struct address_space *); 36 int filemap_fdatawait_keep_errors(struct address_space *mapping); 37 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend); 38 int filemap_fdatawait_range_keep_errors(struct address_space *mapping, 39 loff_t start_byte, loff_t end_byte); 40 41 static inline int filemap_fdatawait(struct address_space *mapping) 42 { 43 return filemap_fdatawait_range(mapping, 0, LLONG_MAX); 44 } 45 46 bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend); 47 int filemap_write_and_wait_range(struct address_space *mapping, 48 loff_t lstart, loff_t lend); 49 int __filemap_fdatawrite_range(struct address_space *mapping, 50 loff_t start, loff_t end, int sync_mode); 51 int filemap_fdatawrite_range(struct address_space *mapping, 52 loff_t start, loff_t end); 53 int filemap_check_errors(struct address_space *mapping); 54 void __filemap_set_wb_err(struct address_space *mapping, int err); 55 int filemap_fdatawrite_wbc(struct address_space *mapping, 56 struct writeback_control *wbc); 57 58 static inline int filemap_write_and_wait(struct address_space *mapping) 59 { 60 return filemap_write_and_wait_range(mapping, 0, LLONG_MAX); 61 } 62 63 /** 64 * filemap_set_wb_err - set a writeback error on an address_space 65 * @mapping: mapping in which to set writeback error 66 * @err: error to be set in mapping 67 * 68 * When writeback fails in some way, we must record that error so that 69 * userspace can be informed when fsync and the like are called. We endeavor 70 * to report errors on any file that was open at the time of the error. Some 71 * internal callers also need to know when writeback errors have occurred. 72 * 73 * When a writeback error occurs, most filesystems will want to call 74 * filemap_set_wb_err to record the error in the mapping so that it will be 75 * automatically reported whenever fsync is called on the file. 76 */ 77 static inline void filemap_set_wb_err(struct address_space *mapping, int err) 78 { 79 /* Fastpath for common case of no error */ 80 if (unlikely(err)) 81 __filemap_set_wb_err(mapping, err); 82 } 83 84 /** 85 * filemap_check_wb_err - has an error occurred since the mark was sampled? 86 * @mapping: mapping to check for writeback errors 87 * @since: previously-sampled errseq_t 88 * 89 * Grab the errseq_t value from the mapping, and see if it has changed "since" 90 * the given value was sampled. 91 * 92 * If it has then report the latest error set, otherwise return 0. 93 */ 94 static inline int filemap_check_wb_err(struct address_space *mapping, 95 errseq_t since) 96 { 97 return errseq_check(&mapping->wb_err, since); 98 } 99 100 /** 101 * filemap_sample_wb_err - sample the current errseq_t to test for later errors 102 * @mapping: mapping to be sampled 103 * 104 * Writeback errors are always reported relative to a particular sample point 105 * in the past. This function provides those sample points. 106 */ 107 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping) 108 { 109 return errseq_sample(&mapping->wb_err); 110 } 111 112 /** 113 * file_sample_sb_err - sample the current errseq_t to test for later errors 114 * @file: file pointer to be sampled 115 * 116 * Grab the most current superblock-level errseq_t value for the given 117 * struct file. 118 */ 119 static inline errseq_t file_sample_sb_err(struct file *file) 120 { 121 return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err); 122 } 123 124 /* 125 * Flush file data before changing attributes. Caller must hold any locks 126 * required to prevent further writes to this file until we're done setting 127 * flags. 128 */ 129 static inline int inode_drain_writes(struct inode *inode) 130 { 131 inode_dio_wait(inode); 132 return filemap_write_and_wait(inode->i_mapping); 133 } 134 135 static inline bool mapping_empty(struct address_space *mapping) 136 { 137 return xa_empty(&mapping->i_pages); 138 } 139 140 /* 141 * mapping_shrinkable - test if page cache state allows inode reclaim 142 * @mapping: the page cache mapping 143 * 144 * This checks the mapping's cache state for the pupose of inode 145 * reclaim and LRU management. 146 * 147 * The caller is expected to hold the i_lock, but is not required to 148 * hold the i_pages lock, which usually protects cache state. That's 149 * because the i_lock and the list_lru lock that protect the inode and 150 * its LRU state don't nest inside the irq-safe i_pages lock. 151 * 152 * Cache deletions are performed under the i_lock, which ensures that 153 * when an inode goes empty, it will reliably get queued on the LRU. 154 * 155 * Cache additions do not acquire the i_lock and may race with this 156 * check, in which case we'll report the inode as shrinkable when it 157 * has cache pages. This is okay: the shrinker also checks the 158 * refcount and the referenced bit, which will be elevated or set in 159 * the process of adding new cache pages to an inode. 160 */ 161 static inline bool mapping_shrinkable(struct address_space *mapping) 162 { 163 void *head; 164 165 /* 166 * On highmem systems, there could be lowmem pressure from the 167 * inodes before there is highmem pressure from the page 168 * cache. Make inodes shrinkable regardless of cache state. 169 */ 170 if (IS_ENABLED(CONFIG_HIGHMEM)) 171 return true; 172 173 /* Cache completely empty? Shrink away. */ 174 head = rcu_access_pointer(mapping->i_pages.xa_head); 175 if (!head) 176 return true; 177 178 /* 179 * The xarray stores single offset-0 entries directly in the 180 * head pointer, which allows non-resident page cache entries 181 * to escape the shadow shrinker's list of xarray nodes. The 182 * inode shrinker needs to pick them up under memory pressure. 183 */ 184 if (!xa_is_node(head) && xa_is_value(head)) 185 return true; 186 187 return false; 188 } 189 190 /* 191 * Bits in mapping->flags. 192 */ 193 enum mapping_flags { 194 AS_EIO = 0, /* IO error on async write */ 195 AS_ENOSPC = 1, /* ENOSPC on async write */ 196 AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */ 197 AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */ 198 AS_EXITING = 4, /* final truncate in progress */ 199 /* writeback related tags are not used */ 200 AS_NO_WRITEBACK_TAGS = 5, 201 AS_LARGE_FOLIO_SUPPORT = 6, 202 }; 203 204 /** 205 * mapping_set_error - record a writeback error in the address_space 206 * @mapping: the mapping in which an error should be set 207 * @error: the error to set in the mapping 208 * 209 * When writeback fails in some way, we must record that error so that 210 * userspace can be informed when fsync and the like are called. We endeavor 211 * to report errors on any file that was open at the time of the error. Some 212 * internal callers also need to know when writeback errors have occurred. 213 * 214 * When a writeback error occurs, most filesystems will want to call 215 * mapping_set_error to record the error in the mapping so that it can be 216 * reported when the application calls fsync(2). 217 */ 218 static inline void mapping_set_error(struct address_space *mapping, int error) 219 { 220 if (likely(!error)) 221 return; 222 223 /* Record in wb_err for checkers using errseq_t based tracking */ 224 __filemap_set_wb_err(mapping, error); 225 226 /* Record it in superblock */ 227 if (mapping->host) 228 errseq_set(&mapping->host->i_sb->s_wb_err, error); 229 230 /* Record it in flags for now, for legacy callers */ 231 if (error == -ENOSPC) 232 set_bit(AS_ENOSPC, &mapping->flags); 233 else 234 set_bit(AS_EIO, &mapping->flags); 235 } 236 237 static inline void mapping_set_unevictable(struct address_space *mapping) 238 { 239 set_bit(AS_UNEVICTABLE, &mapping->flags); 240 } 241 242 static inline void mapping_clear_unevictable(struct address_space *mapping) 243 { 244 clear_bit(AS_UNEVICTABLE, &mapping->flags); 245 } 246 247 static inline bool mapping_unevictable(struct address_space *mapping) 248 { 249 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags); 250 } 251 252 static inline void mapping_set_exiting(struct address_space *mapping) 253 { 254 set_bit(AS_EXITING, &mapping->flags); 255 } 256 257 static inline int mapping_exiting(struct address_space *mapping) 258 { 259 return test_bit(AS_EXITING, &mapping->flags); 260 } 261 262 static inline void mapping_set_no_writeback_tags(struct address_space *mapping) 263 { 264 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 265 } 266 267 static inline int mapping_use_writeback_tags(struct address_space *mapping) 268 { 269 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 270 } 271 272 static inline gfp_t mapping_gfp_mask(struct address_space * mapping) 273 { 274 return mapping->gfp_mask; 275 } 276 277 /* Restricts the given gfp_mask to what the mapping allows. */ 278 static inline gfp_t mapping_gfp_constraint(struct address_space *mapping, 279 gfp_t gfp_mask) 280 { 281 return mapping_gfp_mask(mapping) & gfp_mask; 282 } 283 284 /* 285 * This is non-atomic. Only to be used before the mapping is activated. 286 * Probably needs a barrier... 287 */ 288 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) 289 { 290 m->gfp_mask = mask; 291 } 292 293 /** 294 * mapping_set_large_folios() - Indicate the file supports large folios. 295 * @mapping: The file. 296 * 297 * The filesystem should call this function in its inode constructor to 298 * indicate that the VFS can use large folios to cache the contents of 299 * the file. 300 * 301 * Context: This should not be called while the inode is active as it 302 * is non-atomic. 303 */ 304 static inline void mapping_set_large_folios(struct address_space *mapping) 305 { 306 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); 307 } 308 309 /* 310 * Large folio support currently depends on THP. These dependencies are 311 * being worked on but are not yet fixed. 312 */ 313 static inline bool mapping_large_folio_support(struct address_space *mapping) 314 { 315 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && 316 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); 317 } 318 319 static inline int filemap_nr_thps(struct address_space *mapping) 320 { 321 #ifdef CONFIG_READ_ONLY_THP_FOR_FS 322 return atomic_read(&mapping->nr_thps); 323 #else 324 return 0; 325 #endif 326 } 327 328 static inline void filemap_nr_thps_inc(struct address_space *mapping) 329 { 330 #ifdef CONFIG_READ_ONLY_THP_FOR_FS 331 if (!mapping_large_folio_support(mapping)) 332 atomic_inc(&mapping->nr_thps); 333 #else 334 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); 335 #endif 336 } 337 338 static inline void filemap_nr_thps_dec(struct address_space *mapping) 339 { 340 #ifdef CONFIG_READ_ONLY_THP_FOR_FS 341 if (!mapping_large_folio_support(mapping)) 342 atomic_dec(&mapping->nr_thps); 343 #else 344 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); 345 #endif 346 } 347 348 struct address_space *page_mapping(struct page *); 349 struct address_space *folio_mapping(struct folio *); 350 struct address_space *swapcache_mapping(struct folio *); 351 352 /** 353 * folio_file_mapping - Find the mapping this folio belongs to. 354 * @folio: The folio. 355 * 356 * For folios which are in the page cache, return the mapping that this 357 * page belongs to. Folios in the swap cache return the mapping of the 358 * swap file or swap device where the data is stored. This is different 359 * from the mapping returned by folio_mapping(). The only reason to 360 * use it is if, like NFS, you return 0 from ->activate_swapfile. 361 * 362 * Do not call this for folios which aren't in the page cache or swap cache. 363 */ 364 static inline struct address_space *folio_file_mapping(struct folio *folio) 365 { 366 if (unlikely(folio_test_swapcache(folio))) 367 return swapcache_mapping(folio); 368 369 return folio->mapping; 370 } 371 372 static inline struct address_space *page_file_mapping(struct page *page) 373 { 374 return folio_file_mapping(page_folio(page)); 375 } 376 377 /* 378 * For file cache pages, return the address_space, otherwise return NULL 379 */ 380 static inline struct address_space *page_mapping_file(struct page *page) 381 { 382 struct folio *folio = page_folio(page); 383 384 if (unlikely(folio_test_swapcache(folio))) 385 return NULL; 386 return folio_mapping(folio); 387 } 388 389 /** 390 * folio_inode - Get the host inode for this folio. 391 * @folio: The folio. 392 * 393 * For folios which are in the page cache, return the inode that this folio 394 * belongs to. 395 * 396 * Do not call this for folios which aren't in the page cache. 397 */ 398 static inline struct inode *folio_inode(struct folio *folio) 399 { 400 return folio->mapping->host; 401 } 402 403 /** 404 * folio_attach_private - Attach private data to a folio. 405 * @folio: Folio to attach data to. 406 * @data: Data to attach to folio. 407 * 408 * Attaching private data to a folio increments the page's reference count. 409 * The data must be detached before the folio will be freed. 410 */ 411 static inline void folio_attach_private(struct folio *folio, void *data) 412 { 413 folio_get(folio); 414 folio->private = data; 415 folio_set_private(folio); 416 } 417 418 /** 419 * folio_change_private - Change private data on a folio. 420 * @folio: Folio to change the data on. 421 * @data: Data to set on the folio. 422 * 423 * Change the private data attached to a folio and return the old 424 * data. The page must previously have had data attached and the data 425 * must be detached before the folio will be freed. 426 * 427 * Return: Data that was previously attached to the folio. 428 */ 429 static inline void *folio_change_private(struct folio *folio, void *data) 430 { 431 void *old = folio_get_private(folio); 432 433 folio->private = data; 434 return old; 435 } 436 437 /** 438 * folio_detach_private - Detach private data from a folio. 439 * @folio: Folio to detach data from. 440 * 441 * Removes the data that was previously attached to the folio and decrements 442 * the refcount on the page. 443 * 444 * Return: Data that was attached to the folio. 445 */ 446 static inline void *folio_detach_private(struct folio *folio) 447 { 448 void *data = folio_get_private(folio); 449 450 if (!folio_test_private(folio)) 451 return NULL; 452 folio_clear_private(folio); 453 folio->private = NULL; 454 folio_put(folio); 455 456 return data; 457 } 458 459 static inline void attach_page_private(struct page *page, void *data) 460 { 461 folio_attach_private(page_folio(page), data); 462 } 463 464 static inline void *detach_page_private(struct page *page) 465 { 466 return folio_detach_private(page_folio(page)); 467 } 468 469 #ifdef CONFIG_NUMA 470 struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order); 471 #else 472 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order) 473 { 474 return folio_alloc(gfp, order); 475 } 476 #endif 477 478 static inline struct page *__page_cache_alloc(gfp_t gfp) 479 { 480 return &filemap_alloc_folio(gfp, 0)->page; 481 } 482 483 static inline struct page *page_cache_alloc(struct address_space *x) 484 { 485 return __page_cache_alloc(mapping_gfp_mask(x)); 486 } 487 488 static inline gfp_t readahead_gfp_mask(struct address_space *x) 489 { 490 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN; 491 } 492 493 typedef int filler_t(struct file *, struct folio *); 494 495 pgoff_t page_cache_next_miss(struct address_space *mapping, 496 pgoff_t index, unsigned long max_scan); 497 pgoff_t page_cache_prev_miss(struct address_space *mapping, 498 pgoff_t index, unsigned long max_scan); 499 500 #define FGP_ACCESSED 0x00000001 501 #define FGP_LOCK 0x00000002 502 #define FGP_CREAT 0x00000004 503 #define FGP_WRITE 0x00000008 504 #define FGP_NOFS 0x00000010 505 #define FGP_NOWAIT 0x00000020 506 #define FGP_FOR_MMAP 0x00000040 507 #define FGP_STABLE 0x00000080 508 509 #define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE) 510 511 void *filemap_get_entry(struct address_space *mapping, pgoff_t index); 512 struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, 513 int fgp_flags, gfp_t gfp); 514 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, 515 int fgp_flags, gfp_t gfp); 516 517 /** 518 * filemap_get_folio - Find and get a folio. 519 * @mapping: The address_space to search. 520 * @index: The page index. 521 * 522 * Looks up the page cache entry at @mapping & @index. If a folio is 523 * present, it is returned with an increased refcount. 524 * 525 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for 526 * this index. Will not return a shadow, swap or DAX entry. 527 */ 528 static inline struct folio *filemap_get_folio(struct address_space *mapping, 529 pgoff_t index) 530 { 531 return __filemap_get_folio(mapping, index, 0, 0); 532 } 533 534 /** 535 * filemap_lock_folio - Find and lock a folio. 536 * @mapping: The address_space to search. 537 * @index: The page index. 538 * 539 * Looks up the page cache entry at @mapping & @index. If a folio is 540 * present, it is returned locked with an increased refcount. 541 * 542 * Context: May sleep. 543 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for 544 * this index. Will not return a shadow, swap or DAX entry. 545 */ 546 static inline struct folio *filemap_lock_folio(struct address_space *mapping, 547 pgoff_t index) 548 { 549 return __filemap_get_folio(mapping, index, FGP_LOCK, 0); 550 } 551 552 /** 553 * filemap_grab_folio - grab a folio from the page cache 554 * @mapping: The address space to search 555 * @index: The page index 556 * 557 * Looks up the page cache entry at @mapping & @index. If no folio is found, 558 * a new folio is created. The folio is locked, marked as accessed, and 559 * returned. 560 * 561 * Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found 562 * and failed to create a folio. 563 */ 564 static inline struct folio *filemap_grab_folio(struct address_space *mapping, 565 pgoff_t index) 566 { 567 return __filemap_get_folio(mapping, index, 568 FGP_LOCK | FGP_ACCESSED | FGP_CREAT, 569 mapping_gfp_mask(mapping)); 570 } 571 572 /** 573 * find_get_page - find and get a page reference 574 * @mapping: the address_space to search 575 * @offset: the page index 576 * 577 * Looks up the page cache slot at @mapping & @offset. If there is a 578 * page cache page, it is returned with an increased refcount. 579 * 580 * Otherwise, %NULL is returned. 581 */ 582 static inline struct page *find_get_page(struct address_space *mapping, 583 pgoff_t offset) 584 { 585 return pagecache_get_page(mapping, offset, 0, 0); 586 } 587 588 static inline struct page *find_get_page_flags(struct address_space *mapping, 589 pgoff_t offset, int fgp_flags) 590 { 591 return pagecache_get_page(mapping, offset, fgp_flags, 0); 592 } 593 594 /** 595 * find_lock_page - locate, pin and lock a pagecache page 596 * @mapping: the address_space to search 597 * @index: the page index 598 * 599 * Looks up the page cache entry at @mapping & @index. If there is a 600 * page cache page, it is returned locked and with an increased 601 * refcount. 602 * 603 * Context: May sleep. 604 * Return: A struct page or %NULL if there is no page in the cache for this 605 * index. 606 */ 607 static inline struct page *find_lock_page(struct address_space *mapping, 608 pgoff_t index) 609 { 610 return pagecache_get_page(mapping, index, FGP_LOCK, 0); 611 } 612 613 /** 614 * find_or_create_page - locate or add a pagecache page 615 * @mapping: the page's address_space 616 * @index: the page's index into the mapping 617 * @gfp_mask: page allocation mode 618 * 619 * Looks up the page cache slot at @mapping & @offset. If there is a 620 * page cache page, it is returned locked and with an increased 621 * refcount. 622 * 623 * If the page is not present, a new page is allocated using @gfp_mask 624 * and added to the page cache and the VM's LRU list. The page is 625 * returned locked and with an increased refcount. 626 * 627 * On memory exhaustion, %NULL is returned. 628 * 629 * find_or_create_page() may sleep, even if @gfp_flags specifies an 630 * atomic allocation! 631 */ 632 static inline struct page *find_or_create_page(struct address_space *mapping, 633 pgoff_t index, gfp_t gfp_mask) 634 { 635 return pagecache_get_page(mapping, index, 636 FGP_LOCK|FGP_ACCESSED|FGP_CREAT, 637 gfp_mask); 638 } 639 640 /** 641 * grab_cache_page_nowait - returns locked page at given index in given cache 642 * @mapping: target address_space 643 * @index: the page index 644 * 645 * Same as grab_cache_page(), but do not wait if the page is unavailable. 646 * This is intended for speculative data generators, where the data can 647 * be regenerated if the page couldn't be grabbed. This routine should 648 * be safe to call while holding the lock for another page. 649 * 650 * Clear __GFP_FS when allocating the page to avoid recursion into the fs 651 * and deadlock against the caller's locked page. 652 */ 653 static inline struct page *grab_cache_page_nowait(struct address_space *mapping, 654 pgoff_t index) 655 { 656 return pagecache_get_page(mapping, index, 657 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT, 658 mapping_gfp_mask(mapping)); 659 } 660 661 #define swapcache_index(folio) __page_file_index(&(folio)->page) 662 663 /** 664 * folio_index - File index of a folio. 665 * @folio: The folio. 666 * 667 * For a folio which is either in the page cache or the swap cache, 668 * return its index within the address_space it belongs to. If you know 669 * the page is definitely in the page cache, you can look at the folio's 670 * index directly. 671 * 672 * Return: The index (offset in units of pages) of a folio in its file. 673 */ 674 static inline pgoff_t folio_index(struct folio *folio) 675 { 676 if (unlikely(folio_test_swapcache(folio))) 677 return swapcache_index(folio); 678 return folio->index; 679 } 680 681 /** 682 * folio_next_index - Get the index of the next folio. 683 * @folio: The current folio. 684 * 685 * Return: The index of the folio which follows this folio in the file. 686 */ 687 static inline pgoff_t folio_next_index(struct folio *folio) 688 { 689 return folio->index + folio_nr_pages(folio); 690 } 691 692 /** 693 * folio_file_page - The page for a particular index. 694 * @folio: The folio which contains this index. 695 * @index: The index we want to look up. 696 * 697 * Sometimes after looking up a folio in the page cache, we need to 698 * obtain the specific page for an index (eg a page fault). 699 * 700 * Return: The page containing the file data for this index. 701 */ 702 static inline struct page *folio_file_page(struct folio *folio, pgoff_t index) 703 { 704 /* HugeTLBfs indexes the page cache in units of hpage_size */ 705 if (folio_test_hugetlb(folio)) 706 return &folio->page; 707 return folio_page(folio, index & (folio_nr_pages(folio) - 1)); 708 } 709 710 /** 711 * folio_contains - Does this folio contain this index? 712 * @folio: The folio. 713 * @index: The page index within the file. 714 * 715 * Context: The caller should have the page locked in order to prevent 716 * (eg) shmem from moving the page between the page cache and swap cache 717 * and changing its index in the middle of the operation. 718 * Return: true or false. 719 */ 720 static inline bool folio_contains(struct folio *folio, pgoff_t index) 721 { 722 /* HugeTLBfs indexes the page cache in units of hpage_size */ 723 if (folio_test_hugetlb(folio)) 724 return folio->index == index; 725 return index - folio_index(folio) < folio_nr_pages(folio); 726 } 727 728 /* 729 * Given the page we found in the page cache, return the page corresponding 730 * to this index in the file 731 */ 732 static inline struct page *find_subpage(struct page *head, pgoff_t index) 733 { 734 /* HugeTLBfs wants the head page regardless */ 735 if (PageHuge(head)) 736 return head; 737 738 return head + (index & (thp_nr_pages(head) - 1)); 739 } 740 741 unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start, 742 pgoff_t end, struct folio_batch *fbatch); 743 unsigned filemap_get_folios_contig(struct address_space *mapping, 744 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch); 745 unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start, 746 pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch); 747 748 struct page *grab_cache_page_write_begin(struct address_space *mapping, 749 pgoff_t index); 750 751 /* 752 * Returns locked page at given index in given cache, creating it if needed. 753 */ 754 static inline struct page *grab_cache_page(struct address_space *mapping, 755 pgoff_t index) 756 { 757 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping)); 758 } 759 760 struct folio *read_cache_folio(struct address_space *, pgoff_t index, 761 filler_t *filler, struct file *file); 762 struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index, 763 gfp_t flags); 764 struct page *read_cache_page(struct address_space *, pgoff_t index, 765 filler_t *filler, struct file *file); 766 extern struct page * read_cache_page_gfp(struct address_space *mapping, 767 pgoff_t index, gfp_t gfp_mask); 768 769 static inline struct page *read_mapping_page(struct address_space *mapping, 770 pgoff_t index, struct file *file) 771 { 772 return read_cache_page(mapping, index, NULL, file); 773 } 774 775 static inline struct folio *read_mapping_folio(struct address_space *mapping, 776 pgoff_t index, struct file *file) 777 { 778 return read_cache_folio(mapping, index, NULL, file); 779 } 780 781 /* 782 * Get index of the page within radix-tree (but not for hugetlb pages). 783 * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE) 784 */ 785 static inline pgoff_t page_to_index(struct page *page) 786 { 787 struct page *head; 788 789 if (likely(!PageTransTail(page))) 790 return page->index; 791 792 head = compound_head(page); 793 /* 794 * We don't initialize ->index for tail pages: calculate based on 795 * head page 796 */ 797 return head->index + page - head; 798 } 799 800 extern pgoff_t hugetlb_basepage_index(struct page *page); 801 802 /* 803 * Get the offset in PAGE_SIZE (even for hugetlb pages). 804 * (TODO: hugetlb pages should have ->index in PAGE_SIZE) 805 */ 806 static inline pgoff_t page_to_pgoff(struct page *page) 807 { 808 if (unlikely(PageHuge(page))) 809 return hugetlb_basepage_index(page); 810 return page_to_index(page); 811 } 812 813 /* 814 * Return byte-offset into filesystem object for page. 815 */ 816 static inline loff_t page_offset(struct page *page) 817 { 818 return ((loff_t)page->index) << PAGE_SHIFT; 819 } 820 821 static inline loff_t page_file_offset(struct page *page) 822 { 823 return ((loff_t)page_index(page)) << PAGE_SHIFT; 824 } 825 826 /** 827 * folio_pos - Returns the byte position of this folio in its file. 828 * @folio: The folio. 829 */ 830 static inline loff_t folio_pos(struct folio *folio) 831 { 832 return page_offset(&folio->page); 833 } 834 835 /** 836 * folio_file_pos - Returns the byte position of this folio in its file. 837 * @folio: The folio. 838 * 839 * This differs from folio_pos() for folios which belong to a swap file. 840 * NFS is the only filesystem today which needs to use folio_file_pos(). 841 */ 842 static inline loff_t folio_file_pos(struct folio *folio) 843 { 844 return page_file_offset(&folio->page); 845 } 846 847 /* 848 * Get the offset in PAGE_SIZE (even for hugetlb folios). 849 * (TODO: hugetlb folios should have ->index in PAGE_SIZE) 850 */ 851 static inline pgoff_t folio_pgoff(struct folio *folio) 852 { 853 if (unlikely(folio_test_hugetlb(folio))) 854 return hugetlb_basepage_index(&folio->page); 855 return folio->index; 856 } 857 858 extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 859 unsigned long address); 860 861 static inline pgoff_t linear_page_index(struct vm_area_struct *vma, 862 unsigned long address) 863 { 864 pgoff_t pgoff; 865 if (unlikely(is_vm_hugetlb_page(vma))) 866 return linear_hugepage_index(vma, address); 867 pgoff = (address - vma->vm_start) >> PAGE_SHIFT; 868 pgoff += vma->vm_pgoff; 869 return pgoff; 870 } 871 872 struct wait_page_key { 873 struct folio *folio; 874 int bit_nr; 875 int page_match; 876 }; 877 878 struct wait_page_queue { 879 struct folio *folio; 880 int bit_nr; 881 wait_queue_entry_t wait; 882 }; 883 884 static inline bool wake_page_match(struct wait_page_queue *wait_page, 885 struct wait_page_key *key) 886 { 887 if (wait_page->folio != key->folio) 888 return false; 889 key->page_match = 1; 890 891 if (wait_page->bit_nr != key->bit_nr) 892 return false; 893 894 return true; 895 } 896 897 void __folio_lock(struct folio *folio); 898 int __folio_lock_killable(struct folio *folio); 899 bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, 900 unsigned int flags); 901 void unlock_page(struct page *page); 902 void folio_unlock(struct folio *folio); 903 904 /** 905 * folio_trylock() - Attempt to lock a folio. 906 * @folio: The folio to attempt to lock. 907 * 908 * Sometimes it is undesirable to wait for a folio to be unlocked (eg 909 * when the locks are being taken in the wrong order, or if making 910 * progress through a batch of folios is more important than processing 911 * them in order). Usually folio_lock() is the correct function to call. 912 * 913 * Context: Any context. 914 * Return: Whether the lock was successfully acquired. 915 */ 916 static inline bool folio_trylock(struct folio *folio) 917 { 918 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0))); 919 } 920 921 /* 922 * Return true if the page was successfully locked 923 */ 924 static inline int trylock_page(struct page *page) 925 { 926 return folio_trylock(page_folio(page)); 927 } 928 929 /** 930 * folio_lock() - Lock this folio. 931 * @folio: The folio to lock. 932 * 933 * The folio lock protects against many things, probably more than it 934 * should. It is primarily held while a folio is being brought uptodate, 935 * either from its backing file or from swap. It is also held while a 936 * folio is being truncated from its address_space, so holding the lock 937 * is sufficient to keep folio->mapping stable. 938 * 939 * The folio lock is also held while write() is modifying the page to 940 * provide POSIX atomicity guarantees (as long as the write does not 941 * cross a page boundary). Other modifications to the data in the folio 942 * do not hold the folio lock and can race with writes, eg DMA and stores 943 * to mapped pages. 944 * 945 * Context: May sleep. If you need to acquire the locks of two or 946 * more folios, they must be in order of ascending index, if they are 947 * in the same address_space. If they are in different address_spaces, 948 * acquire the lock of the folio which belongs to the address_space which 949 * has the lowest address in memory first. 950 */ 951 static inline void folio_lock(struct folio *folio) 952 { 953 might_sleep(); 954 if (!folio_trylock(folio)) 955 __folio_lock(folio); 956 } 957 958 /** 959 * lock_page() - Lock the folio containing this page. 960 * @page: The page to lock. 961 * 962 * See folio_lock() for a description of what the lock protects. 963 * This is a legacy function and new code should probably use folio_lock() 964 * instead. 965 * 966 * Context: May sleep. Pages in the same folio share a lock, so do not 967 * attempt to lock two pages which share a folio. 968 */ 969 static inline void lock_page(struct page *page) 970 { 971 struct folio *folio; 972 might_sleep(); 973 974 folio = page_folio(page); 975 if (!folio_trylock(folio)) 976 __folio_lock(folio); 977 } 978 979 /** 980 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal. 981 * @folio: The folio to lock. 982 * 983 * Attempts to lock the folio, like folio_lock(), except that the sleep 984 * to acquire the lock is interruptible by a fatal signal. 985 * 986 * Context: May sleep; see folio_lock(). 987 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received. 988 */ 989 static inline int folio_lock_killable(struct folio *folio) 990 { 991 might_sleep(); 992 if (!folio_trylock(folio)) 993 return __folio_lock_killable(folio); 994 return 0; 995 } 996 997 /* 998 * folio_lock_or_retry - Lock the folio, unless this would block and the 999 * caller indicated that it can handle a retry. 1000 * 1001 * Return value and mmap_lock implications depend on flags; see 1002 * __folio_lock_or_retry(). 1003 */ 1004 static inline bool folio_lock_or_retry(struct folio *folio, 1005 struct mm_struct *mm, unsigned int flags) 1006 { 1007 might_sleep(); 1008 return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags); 1009 } 1010 1011 /* 1012 * This is exported only for folio_wait_locked/folio_wait_writeback, etc., 1013 * and should not be used directly. 1014 */ 1015 void folio_wait_bit(struct folio *folio, int bit_nr); 1016 int folio_wait_bit_killable(struct folio *folio, int bit_nr); 1017 1018 /* 1019 * Wait for a folio to be unlocked. 1020 * 1021 * This must be called with the caller "holding" the folio, 1022 * ie with increased folio reference count so that the folio won't 1023 * go away during the wait. 1024 */ 1025 static inline void folio_wait_locked(struct folio *folio) 1026 { 1027 if (folio_test_locked(folio)) 1028 folio_wait_bit(folio, PG_locked); 1029 } 1030 1031 static inline int folio_wait_locked_killable(struct folio *folio) 1032 { 1033 if (!folio_test_locked(folio)) 1034 return 0; 1035 return folio_wait_bit_killable(folio, PG_locked); 1036 } 1037 1038 static inline void wait_on_page_locked(struct page *page) 1039 { 1040 folio_wait_locked(page_folio(page)); 1041 } 1042 1043 static inline int wait_on_page_locked_killable(struct page *page) 1044 { 1045 return folio_wait_locked_killable(page_folio(page)); 1046 } 1047 1048 void wait_on_page_writeback(struct page *page); 1049 void folio_wait_writeback(struct folio *folio); 1050 int folio_wait_writeback_killable(struct folio *folio); 1051 void end_page_writeback(struct page *page); 1052 void folio_end_writeback(struct folio *folio); 1053 void wait_for_stable_page(struct page *page); 1054 void folio_wait_stable(struct folio *folio); 1055 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn); 1056 static inline void __set_page_dirty(struct page *page, 1057 struct address_space *mapping, int warn) 1058 { 1059 __folio_mark_dirty(page_folio(page), mapping, warn); 1060 } 1061 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb); 1062 void __folio_cancel_dirty(struct folio *folio); 1063 static inline void folio_cancel_dirty(struct folio *folio) 1064 { 1065 /* Avoid atomic ops, locking, etc. when not actually needed. */ 1066 if (folio_test_dirty(folio)) 1067 __folio_cancel_dirty(folio); 1068 } 1069 bool folio_clear_dirty_for_io(struct folio *folio); 1070 bool clear_page_dirty_for_io(struct page *page); 1071 void folio_invalidate(struct folio *folio, size_t offset, size_t length); 1072 int __set_page_dirty_nobuffers(struct page *page); 1073 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio); 1074 1075 #ifdef CONFIG_MIGRATION 1076 int filemap_migrate_folio(struct address_space *mapping, struct folio *dst, 1077 struct folio *src, enum migrate_mode mode); 1078 #else 1079 #define filemap_migrate_folio NULL 1080 #endif 1081 void page_endio(struct page *page, bool is_write, int err); 1082 1083 void folio_end_private_2(struct folio *folio); 1084 void folio_wait_private_2(struct folio *folio); 1085 int folio_wait_private_2_killable(struct folio *folio); 1086 1087 /* 1088 * Add an arbitrary waiter to a page's wait queue 1089 */ 1090 void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter); 1091 1092 /* 1093 * Fault in userspace address range. 1094 */ 1095 size_t fault_in_writeable(char __user *uaddr, size_t size); 1096 size_t fault_in_subpage_writeable(char __user *uaddr, size_t size); 1097 size_t fault_in_safe_writeable(const char __user *uaddr, size_t size); 1098 size_t fault_in_readable(const char __user *uaddr, size_t size); 1099 1100 int add_to_page_cache_lru(struct page *page, struct address_space *mapping, 1101 pgoff_t index, gfp_t gfp); 1102 int filemap_add_folio(struct address_space *mapping, struct folio *folio, 1103 pgoff_t index, gfp_t gfp); 1104 void filemap_remove_folio(struct folio *folio); 1105 void __filemap_remove_folio(struct folio *folio, void *shadow); 1106 void replace_page_cache_folio(struct folio *old, struct folio *new); 1107 void delete_from_page_cache_batch(struct address_space *mapping, 1108 struct folio_batch *fbatch); 1109 bool filemap_release_folio(struct folio *folio, gfp_t gfp); 1110 loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end, 1111 int whence); 1112 1113 /* Must be non-static for BPF error injection */ 1114 int __filemap_add_folio(struct address_space *mapping, struct folio *folio, 1115 pgoff_t index, gfp_t gfp, void **shadowp); 1116 1117 bool filemap_range_has_writeback(struct address_space *mapping, 1118 loff_t start_byte, loff_t end_byte); 1119 1120 /** 1121 * filemap_range_needs_writeback - check if range potentially needs writeback 1122 * @mapping: address space within which to check 1123 * @start_byte: offset in bytes where the range starts 1124 * @end_byte: offset in bytes where the range ends (inclusive) 1125 * 1126 * Find at least one page in the range supplied, usually used to check if 1127 * direct writing in this range will trigger a writeback. Used by O_DIRECT 1128 * read/write with IOCB_NOWAIT, to see if the caller needs to do 1129 * filemap_write_and_wait_range() before proceeding. 1130 * 1131 * Return: %true if the caller should do filemap_write_and_wait_range() before 1132 * doing O_DIRECT to a page in this range, %false otherwise. 1133 */ 1134 static inline bool filemap_range_needs_writeback(struct address_space *mapping, 1135 loff_t start_byte, 1136 loff_t end_byte) 1137 { 1138 if (!mapping->nrpages) 1139 return false; 1140 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && 1141 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) 1142 return false; 1143 return filemap_range_has_writeback(mapping, start_byte, end_byte); 1144 } 1145 1146 /** 1147 * struct readahead_control - Describes a readahead request. 1148 * 1149 * A readahead request is for consecutive pages. Filesystems which 1150 * implement the ->readahead method should call readahead_page() or 1151 * readahead_page_batch() in a loop and attempt to start I/O against 1152 * each page in the request. 1153 * 1154 * Most of the fields in this struct are private and should be accessed 1155 * by the functions below. 1156 * 1157 * @file: The file, used primarily by network filesystems for authentication. 1158 * May be NULL if invoked internally by the filesystem. 1159 * @mapping: Readahead this filesystem object. 1160 * @ra: File readahead state. May be NULL. 1161 */ 1162 struct readahead_control { 1163 struct file *file; 1164 struct address_space *mapping; 1165 struct file_ra_state *ra; 1166 /* private: use the readahead_* accessors instead */ 1167 pgoff_t _index; 1168 unsigned int _nr_pages; 1169 unsigned int _batch_count; 1170 bool _workingset; 1171 unsigned long _pflags; 1172 }; 1173 1174 #define DEFINE_READAHEAD(ractl, f, r, m, i) \ 1175 struct readahead_control ractl = { \ 1176 .file = f, \ 1177 .mapping = m, \ 1178 .ra = r, \ 1179 ._index = i, \ 1180 } 1181 1182 #define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE) 1183 1184 void page_cache_ra_unbounded(struct readahead_control *, 1185 unsigned long nr_to_read, unsigned long lookahead_count); 1186 void page_cache_sync_ra(struct readahead_control *, unsigned long req_count); 1187 void page_cache_async_ra(struct readahead_control *, struct folio *, 1188 unsigned long req_count); 1189 void readahead_expand(struct readahead_control *ractl, 1190 loff_t new_start, size_t new_len); 1191 1192 /** 1193 * page_cache_sync_readahead - generic file readahead 1194 * @mapping: address_space which holds the pagecache and I/O vectors 1195 * @ra: file_ra_state which holds the readahead state 1196 * @file: Used by the filesystem for authentication. 1197 * @index: Index of first page to be read. 1198 * @req_count: Total number of pages being read by the caller. 1199 * 1200 * page_cache_sync_readahead() should be called when a cache miss happened: 1201 * it will submit the read. The readahead logic may decide to piggyback more 1202 * pages onto the read request if access patterns suggest it will improve 1203 * performance. 1204 */ 1205 static inline 1206 void page_cache_sync_readahead(struct address_space *mapping, 1207 struct file_ra_state *ra, struct file *file, pgoff_t index, 1208 unsigned long req_count) 1209 { 1210 DEFINE_READAHEAD(ractl, file, ra, mapping, index); 1211 page_cache_sync_ra(&ractl, req_count); 1212 } 1213 1214 /** 1215 * page_cache_async_readahead - file readahead for marked pages 1216 * @mapping: address_space which holds the pagecache and I/O vectors 1217 * @ra: file_ra_state which holds the readahead state 1218 * @file: Used by the filesystem for authentication. 1219 * @folio: The folio at @index which triggered the readahead call. 1220 * @index: Index of first page to be read. 1221 * @req_count: Total number of pages being read by the caller. 1222 * 1223 * page_cache_async_readahead() should be called when a page is used which 1224 * is marked as PageReadahead; this is a marker to suggest that the application 1225 * has used up enough of the readahead window that we should start pulling in 1226 * more pages. 1227 */ 1228 static inline 1229 void page_cache_async_readahead(struct address_space *mapping, 1230 struct file_ra_state *ra, struct file *file, 1231 struct folio *folio, pgoff_t index, unsigned long req_count) 1232 { 1233 DEFINE_READAHEAD(ractl, file, ra, mapping, index); 1234 page_cache_async_ra(&ractl, folio, req_count); 1235 } 1236 1237 static inline struct folio *__readahead_folio(struct readahead_control *ractl) 1238 { 1239 struct folio *folio; 1240 1241 BUG_ON(ractl->_batch_count > ractl->_nr_pages); 1242 ractl->_nr_pages -= ractl->_batch_count; 1243 ractl->_index += ractl->_batch_count; 1244 1245 if (!ractl->_nr_pages) { 1246 ractl->_batch_count = 0; 1247 return NULL; 1248 } 1249 1250 folio = xa_load(&ractl->mapping->i_pages, ractl->_index); 1251 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 1252 ractl->_batch_count = folio_nr_pages(folio); 1253 1254 return folio; 1255 } 1256 1257 /** 1258 * readahead_page - Get the next page to read. 1259 * @ractl: The current readahead request. 1260 * 1261 * Context: The page is locked and has an elevated refcount. The caller 1262 * should decreases the refcount once the page has been submitted for I/O 1263 * and unlock the page once all I/O to that page has completed. 1264 * Return: A pointer to the next page, or %NULL if we are done. 1265 */ 1266 static inline struct page *readahead_page(struct readahead_control *ractl) 1267 { 1268 struct folio *folio = __readahead_folio(ractl); 1269 1270 return &folio->page; 1271 } 1272 1273 /** 1274 * readahead_folio - Get the next folio to read. 1275 * @ractl: The current readahead request. 1276 * 1277 * Context: The folio is locked. The caller should unlock the folio once 1278 * all I/O to that folio has completed. 1279 * Return: A pointer to the next folio, or %NULL if we are done. 1280 */ 1281 static inline struct folio *readahead_folio(struct readahead_control *ractl) 1282 { 1283 struct folio *folio = __readahead_folio(ractl); 1284 1285 if (folio) 1286 folio_put(folio); 1287 return folio; 1288 } 1289 1290 static inline unsigned int __readahead_batch(struct readahead_control *rac, 1291 struct page **array, unsigned int array_sz) 1292 { 1293 unsigned int i = 0; 1294 XA_STATE(xas, &rac->mapping->i_pages, 0); 1295 struct page *page; 1296 1297 BUG_ON(rac->_batch_count > rac->_nr_pages); 1298 rac->_nr_pages -= rac->_batch_count; 1299 rac->_index += rac->_batch_count; 1300 rac->_batch_count = 0; 1301 1302 xas_set(&xas, rac->_index); 1303 rcu_read_lock(); 1304 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) { 1305 if (xas_retry(&xas, page)) 1306 continue; 1307 VM_BUG_ON_PAGE(!PageLocked(page), page); 1308 VM_BUG_ON_PAGE(PageTail(page), page); 1309 array[i++] = page; 1310 rac->_batch_count += thp_nr_pages(page); 1311 if (i == array_sz) 1312 break; 1313 } 1314 rcu_read_unlock(); 1315 1316 return i; 1317 } 1318 1319 /** 1320 * readahead_page_batch - Get a batch of pages to read. 1321 * @rac: The current readahead request. 1322 * @array: An array of pointers to struct page. 1323 * 1324 * Context: The pages are locked and have an elevated refcount. The caller 1325 * should decreases the refcount once the page has been submitted for I/O 1326 * and unlock the page once all I/O to that page has completed. 1327 * Return: The number of pages placed in the array. 0 indicates the request 1328 * is complete. 1329 */ 1330 #define readahead_page_batch(rac, array) \ 1331 __readahead_batch(rac, array, ARRAY_SIZE(array)) 1332 1333 /** 1334 * readahead_pos - The byte offset into the file of this readahead request. 1335 * @rac: The readahead request. 1336 */ 1337 static inline loff_t readahead_pos(struct readahead_control *rac) 1338 { 1339 return (loff_t)rac->_index * PAGE_SIZE; 1340 } 1341 1342 /** 1343 * readahead_length - The number of bytes in this readahead request. 1344 * @rac: The readahead request. 1345 */ 1346 static inline size_t readahead_length(struct readahead_control *rac) 1347 { 1348 return rac->_nr_pages * PAGE_SIZE; 1349 } 1350 1351 /** 1352 * readahead_index - The index of the first page in this readahead request. 1353 * @rac: The readahead request. 1354 */ 1355 static inline pgoff_t readahead_index(struct readahead_control *rac) 1356 { 1357 return rac->_index; 1358 } 1359 1360 /** 1361 * readahead_count - The number of pages in this readahead request. 1362 * @rac: The readahead request. 1363 */ 1364 static inline unsigned int readahead_count(struct readahead_control *rac) 1365 { 1366 return rac->_nr_pages; 1367 } 1368 1369 /** 1370 * readahead_batch_length - The number of bytes in the current batch. 1371 * @rac: The readahead request. 1372 */ 1373 static inline size_t readahead_batch_length(struct readahead_control *rac) 1374 { 1375 return rac->_batch_count * PAGE_SIZE; 1376 } 1377 1378 static inline unsigned long dir_pages(struct inode *inode) 1379 { 1380 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >> 1381 PAGE_SHIFT; 1382 } 1383 1384 /** 1385 * folio_mkwrite_check_truncate - check if folio was truncated 1386 * @folio: the folio to check 1387 * @inode: the inode to check the folio against 1388 * 1389 * Return: the number of bytes in the folio up to EOF, 1390 * or -EFAULT if the folio was truncated. 1391 */ 1392 static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio, 1393 struct inode *inode) 1394 { 1395 loff_t size = i_size_read(inode); 1396 pgoff_t index = size >> PAGE_SHIFT; 1397 size_t offset = offset_in_folio(folio, size); 1398 1399 if (!folio->mapping) 1400 return -EFAULT; 1401 1402 /* folio is wholly inside EOF */ 1403 if (folio_next_index(folio) - 1 < index) 1404 return folio_size(folio); 1405 /* folio is wholly past EOF */ 1406 if (folio->index > index || !offset) 1407 return -EFAULT; 1408 /* folio is partially inside EOF */ 1409 return offset; 1410 } 1411 1412 /** 1413 * page_mkwrite_check_truncate - check if page was truncated 1414 * @page: the page to check 1415 * @inode: the inode to check the page against 1416 * 1417 * Returns the number of bytes in the page up to EOF, 1418 * or -EFAULT if the page was truncated. 1419 */ 1420 static inline int page_mkwrite_check_truncate(struct page *page, 1421 struct inode *inode) 1422 { 1423 loff_t size = i_size_read(inode); 1424 pgoff_t index = size >> PAGE_SHIFT; 1425 int offset = offset_in_page(size); 1426 1427 if (page->mapping != inode->i_mapping) 1428 return -EFAULT; 1429 1430 /* page is wholly inside EOF */ 1431 if (page->index < index) 1432 return PAGE_SIZE; 1433 /* page is wholly past EOF */ 1434 if (page->index > index || !offset) 1435 return -EFAULT; 1436 /* page is partially inside EOF */ 1437 return offset; 1438 } 1439 1440 /** 1441 * i_blocks_per_folio - How many blocks fit in this folio. 1442 * @inode: The inode which contains the blocks. 1443 * @folio: The folio. 1444 * 1445 * If the block size is larger than the size of this folio, return zero. 1446 * 1447 * Context: The caller should hold a refcount on the folio to prevent it 1448 * from being split. 1449 * Return: The number of filesystem blocks covered by this folio. 1450 */ 1451 static inline 1452 unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio) 1453 { 1454 return folio_size(folio) >> inode->i_blkbits; 1455 } 1456 1457 static inline 1458 unsigned int i_blocks_per_page(struct inode *inode, struct page *page) 1459 { 1460 return i_blocks_per_folio(inode, page_folio(page)); 1461 } 1462 #endif /* _LINUX_PAGEMAP_H */ 1463