1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_DCACHE_H 3 #define __LINUX_DCACHE_H 4 5 #include <linux/atomic.h> 6 #include <linux/list.h> 7 #include <linux/math.h> 8 #include <linux/rculist.h> 9 #include <linux/rculist_bl.h> 10 #include <linux/spinlock.h> 11 #include <linux/seqlock.h> 12 #include <linux/cache.h> 13 #include <linux/rcupdate.h> 14 #include <linux/lockref.h> 15 #include <linux/stringhash.h> 16 #include <linux/wait.h> 17 18 struct path; 19 struct file; 20 struct vfsmount; 21 22 /* 23 * linux/include/linux/dcache.h 24 * 25 * Dirent cache data structures 26 * 27 * (C) Copyright 1997 Thomas Schoebel-Theuer, 28 * with heavy changes by Linus Torvalds 29 */ 30 31 #define IS_ROOT(x) ((x) == (x)->d_parent) 32 33 /* The hash is always the low bits of hash_len */ 34 #ifdef __LITTLE_ENDIAN 35 #define HASH_LEN_DECLARE u32 hash; u32 len 36 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8)) 37 #else 38 #define HASH_LEN_DECLARE u32 len; u32 hash 39 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8)) 40 #endif 41 42 /* 43 * "quick string" -- eases parameter passing, but more importantly 44 * saves "metadata" about the string (ie length and the hash). 45 * 46 * hash comes first so it snuggles against d_parent in the 47 * dentry. 48 */ 49 struct qstr { 50 union { 51 struct { 52 HASH_LEN_DECLARE; 53 }; 54 u64 hash_len; 55 }; 56 const unsigned char *name; 57 }; 58 59 #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } 60 61 extern const struct qstr empty_name; 62 extern const struct qstr slash_name; 63 extern const struct qstr dotdot_name; 64 65 /* 66 * Try to keep struct dentry aligned on 64 byte cachelines (this will 67 * give reasonable cacheline footprint with larger lines without the 68 * large memory footprint increase). 69 */ 70 #ifdef CONFIG_64BIT 71 # define DNAME_INLINE_LEN 40 /* 192 bytes */ 72 #else 73 # ifdef CONFIG_SMP 74 # define DNAME_INLINE_LEN 36 /* 128 bytes */ 75 # else 76 # define DNAME_INLINE_LEN 44 /* 128 bytes */ 77 # endif 78 #endif 79 80 #define d_lock d_lockref.lock 81 82 struct dentry { 83 /* RCU lookup touched fields */ 84 unsigned int d_flags; /* protected by d_lock */ 85 seqcount_spinlock_t d_seq; /* per dentry seqlock */ 86 struct hlist_bl_node d_hash; /* lookup hash list */ 87 struct dentry *d_parent; /* parent directory */ 88 struct qstr d_name; 89 struct inode *d_inode; /* Where the name belongs to - NULL is 90 * negative */ 91 unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ 92 /* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */ 93 94 /* Ref lookup also touches following */ 95 const struct dentry_operations *d_op; 96 struct super_block *d_sb; /* The root of the dentry tree */ 97 unsigned long d_time; /* used by d_revalidate */ 98 void *d_fsdata; /* fs-specific data */ 99 /* --- cacheline 2 boundary (128 bytes) --- */ 100 struct lockref d_lockref; /* per-dentry lock and refcount 101 * keep separate from RCU lookup area if 102 * possible! 103 */ 104 105 union { 106 struct list_head d_lru; /* LRU list */ 107 wait_queue_head_t *d_wait; /* in-lookup ones only */ 108 }; 109 struct hlist_node d_sib; /* child of parent list */ 110 struct hlist_head d_children; /* our children */ 111 /* 112 * d_alias and d_rcu can share memory 113 */ 114 union { 115 struct hlist_node d_alias; /* inode alias list */ 116 struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ 117 struct rcu_head d_rcu; 118 } d_u; 119 }; 120 121 /* 122 * dentry->d_lock spinlock nesting subclasses: 123 * 124 * 0: normal 125 * 1: nested 126 */ 127 enum dentry_d_lock_class 128 { 129 DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ 130 DENTRY_D_LOCK_NESTED 131 }; 132 133 enum d_real_type { 134 D_REAL_DATA, 135 D_REAL_METADATA, 136 }; 137 138 struct dentry_operations { 139 int (*d_revalidate)(struct dentry *, unsigned int); 140 int (*d_weak_revalidate)(struct dentry *, unsigned int); 141 int (*d_hash)(const struct dentry *, struct qstr *); 142 int (*d_compare)(const struct dentry *, 143 unsigned int, const char *, const struct qstr *); 144 int (*d_delete)(const struct dentry *); 145 int (*d_init)(struct dentry *); 146 void (*d_release)(struct dentry *); 147 void (*d_prune)(struct dentry *); 148 void (*d_iput)(struct dentry *, struct inode *); 149 char *(*d_dname)(struct dentry *, char *, int); 150 struct vfsmount *(*d_automount)(struct path *); 151 int (*d_manage)(const struct path *, bool); 152 struct dentry *(*d_real)(struct dentry *, enum d_real_type type); 153 } ____cacheline_aligned; 154 155 /* 156 * Locking rules for dentry_operations callbacks are to be found in 157 * Documentation/filesystems/locking.rst. Keep it updated! 158 * 159 * FUrther descriptions are found in Documentation/filesystems/vfs.rst. 160 * Keep it updated too! 161 */ 162 163 /* d_flags entries */ 164 #define DCACHE_OP_HASH BIT(0) 165 #define DCACHE_OP_COMPARE BIT(1) 166 #define DCACHE_OP_REVALIDATE BIT(2) 167 #define DCACHE_OP_DELETE BIT(3) 168 #define DCACHE_OP_PRUNE BIT(4) 169 170 #define DCACHE_DISCONNECTED BIT(5) 171 /* This dentry is possibly not currently connected to the dcache tree, in 172 * which case its parent will either be itself, or will have this flag as 173 * well. nfsd will not use a dentry with this bit set, but will first 174 * endeavour to clear the bit either by discovering that it is connected, 175 * or by performing lookup operations. Any filesystem which supports 176 * nfsd_operations MUST have a lookup function which, if it finds a 177 * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that 178 * dentry into place and return that dentry rather than the passed one, 179 * typically using d_splice_alias. */ 180 181 #define DCACHE_REFERENCED BIT(6) /* Recently used, don't discard. */ 182 183 #define DCACHE_DONTCACHE BIT(7) /* Purge from memory on final dput() */ 184 185 #define DCACHE_CANT_MOUNT BIT(8) 186 #define DCACHE_GENOCIDE BIT(9) 187 #define DCACHE_SHRINK_LIST BIT(10) 188 189 #define DCACHE_OP_WEAK_REVALIDATE BIT(11) 190 191 #define DCACHE_NFSFS_RENAMED BIT(12) 192 /* this dentry has been "silly renamed" and has to be deleted on the last 193 * dput() */ 194 #define DCACHE_FSNOTIFY_PARENT_WATCHED BIT(14) 195 /* Parent inode is watched by some fsnotify listener */ 196 197 #define DCACHE_DENTRY_KILLED BIT(15) 198 199 #define DCACHE_MOUNTED BIT(16) /* is a mountpoint */ 200 #define DCACHE_NEED_AUTOMOUNT BIT(17) /* handle automount on this dir */ 201 #define DCACHE_MANAGE_TRANSIT BIT(18) /* manage transit from this dirent */ 202 #define DCACHE_MANAGED_DENTRY \ 203 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) 204 205 #define DCACHE_LRU_LIST BIT(19) 206 207 #define DCACHE_ENTRY_TYPE (7 << 20) /* bits 20..22 are for storing type: */ 208 #define DCACHE_MISS_TYPE (0 << 20) /* Negative dentry */ 209 #define DCACHE_WHITEOUT_TYPE (1 << 20) /* Whiteout dentry (stop pathwalk) */ 210 #define DCACHE_DIRECTORY_TYPE (2 << 20) /* Normal directory */ 211 #define DCACHE_AUTODIR_TYPE (3 << 20) /* Lookupless directory (presumed automount) */ 212 #define DCACHE_REGULAR_TYPE (4 << 20) /* Regular file type */ 213 #define DCACHE_SPECIAL_TYPE (5 << 20) /* Other file type */ 214 #define DCACHE_SYMLINK_TYPE (6 << 20) /* Symlink */ 215 216 #define DCACHE_NOKEY_NAME BIT(25) /* Encrypted name encoded without key */ 217 #define DCACHE_OP_REAL BIT(26) 218 219 #define DCACHE_PAR_LOOKUP BIT(28) /* being looked up (with parent locked shared) */ 220 #define DCACHE_DENTRY_CURSOR BIT(29) 221 #define DCACHE_NORCU BIT(30) /* No RCU delay for freeing */ 222 223 extern seqlock_t rename_lock; 224 225 /* 226 * These are the low-level FS interfaces to the dcache.. 227 */ 228 extern void d_instantiate(struct dentry *, struct inode *); 229 extern void d_instantiate_new(struct dentry *, struct inode *); 230 extern void __d_drop(struct dentry *dentry); 231 extern void d_drop(struct dentry *dentry); 232 extern void d_delete(struct dentry *); 233 extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); 234 235 /* allocate/de-allocate */ 236 extern struct dentry * d_alloc(struct dentry *, const struct qstr *); 237 extern struct dentry * d_alloc_anon(struct super_block *); 238 extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, 239 wait_queue_head_t *); 240 extern struct dentry * d_splice_alias(struct inode *, struct dentry *); 241 extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); 242 extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent, 243 const struct qstr *name); 244 extern struct dentry * d_exact_alias(struct dentry *, struct inode *); 245 extern struct dentry *d_find_any_alias(struct inode *inode); 246 extern struct dentry * d_obtain_alias(struct inode *); 247 extern struct dentry * d_obtain_root(struct inode *); 248 extern void shrink_dcache_sb(struct super_block *); 249 extern void shrink_dcache_parent(struct dentry *); 250 extern void d_invalidate(struct dentry *); 251 252 /* only used at mount-time */ 253 extern struct dentry * d_make_root(struct inode *); 254 255 extern void d_mark_tmpfile(struct file *, struct inode *); 256 extern void d_tmpfile(struct file *, struct inode *); 257 258 extern struct dentry *d_find_alias(struct inode *); 259 extern void d_prune_aliases(struct inode *); 260 261 extern struct dentry *d_find_alias_rcu(struct inode *); 262 263 /* test whether we have any submounts in a subdir tree */ 264 extern int path_has_submounts(const struct path *); 265 266 /* 267 * This adds the entry to the hash queues. 268 */ 269 extern void d_rehash(struct dentry *); 270 271 extern void d_add(struct dentry *, struct inode *); 272 273 /* used for rename() and baskets */ 274 extern void d_move(struct dentry *, struct dentry *); 275 extern void d_exchange(struct dentry *, struct dentry *); 276 extern struct dentry *d_ancestor(struct dentry *, struct dentry *); 277 278 extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); 279 extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); 280 d_count(const struct dentry * dentry)281 static inline unsigned d_count(const struct dentry *dentry) 282 { 283 return dentry->d_lockref.count; 284 } 285 286 ino_t d_parent_ino(struct dentry *dentry); 287 288 /* 289 * helper function for dentry_operations.d_dname() members 290 */ 291 extern __printf(3, 4) 292 char *dynamic_dname(char *, int, const char *, ...); 293 294 extern char *__d_path(const struct path *, const struct path *, char *, int); 295 extern char *d_absolute_path(const struct path *, char *, int); 296 extern char *d_path(const struct path *, char *, int); 297 extern char *dentry_path_raw(const struct dentry *, char *, int); 298 extern char *dentry_path(const struct dentry *, char *, int); 299 300 /* Allocation counts.. */ 301 302 /** 303 * dget_dlock - get a reference to a dentry 304 * @dentry: dentry to get a reference to 305 * 306 * Given a live dentry, increment the reference count and return the dentry. 307 * Caller must hold @dentry->d_lock. Making sure that dentry is alive is 308 * caller's resonsibility. There are many conditions sufficient to guarantee 309 * that; e.g. anything with non-negative refcount is alive, so's anything 310 * hashed, anything positive, anyone's parent, etc. 311 */ dget_dlock(struct dentry * dentry)312 static inline struct dentry *dget_dlock(struct dentry *dentry) 313 { 314 dentry->d_lockref.count++; 315 return dentry; 316 } 317 318 319 /** 320 * dget - get a reference to a dentry 321 * @dentry: dentry to get a reference to 322 * 323 * Given a dentry or %NULL pointer increment the reference count 324 * if appropriate and return the dentry. A dentry will not be 325 * destroyed when it has references. Conversely, a dentry with 326 * no references can disappear for any number of reasons, starting 327 * with memory pressure. In other words, that primitive is 328 * used to clone an existing reference; using it on something with 329 * zero refcount is a bug. 330 * 331 * NOTE: it will spin if @dentry->d_lock is held. From the deadlock 332 * avoidance point of view it is equivalent to spin_lock()/increment 333 * refcount/spin_unlock(), so calling it under @dentry->d_lock is 334 * always a bug; so's calling it under ->d_lock on any of its descendents. 335 * 336 */ dget(struct dentry * dentry)337 static inline struct dentry *dget(struct dentry *dentry) 338 { 339 if (dentry) 340 lockref_get(&dentry->d_lockref); 341 return dentry; 342 } 343 344 extern struct dentry *dget_parent(struct dentry *dentry); 345 346 /** 347 * d_unhashed - is dentry hashed 348 * @dentry: entry to check 349 * 350 * Returns true if the dentry passed is not currently hashed. 351 */ d_unhashed(const struct dentry * dentry)352 static inline int d_unhashed(const struct dentry *dentry) 353 { 354 return hlist_bl_unhashed(&dentry->d_hash); 355 } 356 d_unlinked(const struct dentry * dentry)357 static inline int d_unlinked(const struct dentry *dentry) 358 { 359 return d_unhashed(dentry) && !IS_ROOT(dentry); 360 } 361 cant_mount(const struct dentry * dentry)362 static inline int cant_mount(const struct dentry *dentry) 363 { 364 return (dentry->d_flags & DCACHE_CANT_MOUNT); 365 } 366 dont_mount(struct dentry * dentry)367 static inline void dont_mount(struct dentry *dentry) 368 { 369 spin_lock(&dentry->d_lock); 370 dentry->d_flags |= DCACHE_CANT_MOUNT; 371 spin_unlock(&dentry->d_lock); 372 } 373 374 extern void __d_lookup_unhash_wake(struct dentry *dentry); 375 d_in_lookup(const struct dentry * dentry)376 static inline int d_in_lookup(const struct dentry *dentry) 377 { 378 return dentry->d_flags & DCACHE_PAR_LOOKUP; 379 } 380 d_lookup_done(struct dentry * dentry)381 static inline void d_lookup_done(struct dentry *dentry) 382 { 383 if (unlikely(d_in_lookup(dentry))) 384 __d_lookup_unhash_wake(dentry); 385 } 386 387 extern void dput(struct dentry *); 388 d_managed(const struct dentry * dentry)389 static inline bool d_managed(const struct dentry *dentry) 390 { 391 return dentry->d_flags & DCACHE_MANAGED_DENTRY; 392 } 393 d_mountpoint(const struct dentry * dentry)394 static inline bool d_mountpoint(const struct dentry *dentry) 395 { 396 return dentry->d_flags & DCACHE_MOUNTED; 397 } 398 399 /* 400 * Directory cache entry type accessor functions. 401 */ __d_entry_type(const struct dentry * dentry)402 static inline unsigned __d_entry_type(const struct dentry *dentry) 403 { 404 return dentry->d_flags & DCACHE_ENTRY_TYPE; 405 } 406 d_is_miss(const struct dentry * dentry)407 static inline bool d_is_miss(const struct dentry *dentry) 408 { 409 return __d_entry_type(dentry) == DCACHE_MISS_TYPE; 410 } 411 d_is_whiteout(const struct dentry * dentry)412 static inline bool d_is_whiteout(const struct dentry *dentry) 413 { 414 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; 415 } 416 d_can_lookup(const struct dentry * dentry)417 static inline bool d_can_lookup(const struct dentry *dentry) 418 { 419 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; 420 } 421 d_is_autodir(const struct dentry * dentry)422 static inline bool d_is_autodir(const struct dentry *dentry) 423 { 424 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; 425 } 426 d_is_dir(const struct dentry * dentry)427 static inline bool d_is_dir(const struct dentry *dentry) 428 { 429 return d_can_lookup(dentry) || d_is_autodir(dentry); 430 } 431 d_is_symlink(const struct dentry * dentry)432 static inline bool d_is_symlink(const struct dentry *dentry) 433 { 434 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; 435 } 436 d_is_reg(const struct dentry * dentry)437 static inline bool d_is_reg(const struct dentry *dentry) 438 { 439 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; 440 } 441 d_is_special(const struct dentry * dentry)442 static inline bool d_is_special(const struct dentry *dentry) 443 { 444 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; 445 } 446 d_is_file(const struct dentry * dentry)447 static inline bool d_is_file(const struct dentry *dentry) 448 { 449 return d_is_reg(dentry) || d_is_special(dentry); 450 } 451 d_is_negative(const struct dentry * dentry)452 static inline bool d_is_negative(const struct dentry *dentry) 453 { 454 // TODO: check d_is_whiteout(dentry) also. 455 return d_is_miss(dentry); 456 } 457 d_flags_negative(unsigned flags)458 static inline bool d_flags_negative(unsigned flags) 459 { 460 return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE; 461 } 462 d_is_positive(const struct dentry * dentry)463 static inline bool d_is_positive(const struct dentry *dentry) 464 { 465 return !d_is_negative(dentry); 466 } 467 468 /** 469 * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) 470 * @dentry: The dentry in question 471 * 472 * Returns true if the dentry represents either an absent name or a name that 473 * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent 474 * a true miss, a whiteout that isn't represented by a 0,0 chardev or a 475 * fallthrough marker in an opaque directory. 476 * 477 * Note! (1) This should be used *only* by a filesystem to examine its own 478 * dentries. It should not be used to look at some other filesystem's 479 * dentries. (2) It should also be used in combination with d_inode() to get 480 * the inode. (3) The dentry may have something attached to ->d_lower and the 481 * type field of the flags may be set to something other than miss or whiteout. 482 */ d_really_is_negative(const struct dentry * dentry)483 static inline bool d_really_is_negative(const struct dentry *dentry) 484 { 485 return dentry->d_inode == NULL; 486 } 487 488 /** 489 * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) 490 * @dentry: The dentry in question 491 * 492 * Returns true if the dentry represents a name that maps to an inode 493 * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if 494 * that is represented on medium as a 0,0 chardev. 495 * 496 * Note! (1) This should be used *only* by a filesystem to examine its own 497 * dentries. It should not be used to look at some other filesystem's 498 * dentries. (2) It should also be used in combination with d_inode() to get 499 * the inode. 500 */ d_really_is_positive(const struct dentry * dentry)501 static inline bool d_really_is_positive(const struct dentry *dentry) 502 { 503 return dentry->d_inode != NULL; 504 } 505 simple_positive(const struct dentry * dentry)506 static inline int simple_positive(const struct dentry *dentry) 507 { 508 return d_really_is_positive(dentry) && !d_unhashed(dentry); 509 } 510 511 extern int sysctl_vfs_cache_pressure; 512 vfs_pressure_ratio(unsigned long val)513 static inline unsigned long vfs_pressure_ratio(unsigned long val) 514 { 515 return mult_frac(val, sysctl_vfs_cache_pressure, 100); 516 } 517 518 /** 519 * d_inode - Get the actual inode of this dentry 520 * @dentry: The dentry to query 521 * 522 * This is the helper normal filesystems should use to get at their own inodes 523 * in their own dentries and ignore the layering superimposed upon them. 524 */ d_inode(const struct dentry * dentry)525 static inline struct inode *d_inode(const struct dentry *dentry) 526 { 527 return dentry->d_inode; 528 } 529 530 /** 531 * d_inode_rcu - Get the actual inode of this dentry with READ_ONCE() 532 * @dentry: The dentry to query 533 * 534 * This is the helper normal filesystems should use to get at their own inodes 535 * in their own dentries and ignore the layering superimposed upon them. 536 */ d_inode_rcu(const struct dentry * dentry)537 static inline struct inode *d_inode_rcu(const struct dentry *dentry) 538 { 539 return READ_ONCE(dentry->d_inode); 540 } 541 542 /** 543 * d_backing_inode - Get upper or lower inode we should be using 544 * @upper: The upper layer 545 * 546 * This is the helper that should be used to get at the inode that will be used 547 * if this dentry were to be opened as a file. The inode may be on the upper 548 * dentry or it may be on a lower dentry pinned by the upper. 549 * 550 * Normal filesystems should not use this to access their own inodes. 551 */ d_backing_inode(const struct dentry * upper)552 static inline struct inode *d_backing_inode(const struct dentry *upper) 553 { 554 struct inode *inode = upper->d_inode; 555 556 return inode; 557 } 558 559 /** 560 * d_real - Return the real dentry 561 * @dentry: the dentry to query 562 * @type: the type of real dentry (data or metadata) 563 * 564 * If dentry is on a union/overlay, then return the underlying, real dentry. 565 * Otherwise return the dentry itself. 566 * 567 * See also: Documentation/filesystems/vfs.rst 568 */ d_real(struct dentry * dentry,enum d_real_type type)569 static inline struct dentry *d_real(struct dentry *dentry, enum d_real_type type) 570 { 571 if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) 572 return dentry->d_op->d_real(dentry, type); 573 else 574 return dentry; 575 } 576 577 /** 578 * d_real_inode - Return the real inode hosting the data 579 * @dentry: The dentry to query 580 * 581 * If dentry is on a union/overlay, then return the underlying, real inode. 582 * Otherwise return d_inode(). 583 */ d_real_inode(const struct dentry * dentry)584 static inline struct inode *d_real_inode(const struct dentry *dentry) 585 { 586 /* This usage of d_real() results in const dentry */ 587 return d_inode(d_real((struct dentry *) dentry, D_REAL_DATA)); 588 } 589 590 struct name_snapshot { 591 struct qstr name; 592 unsigned char inline_name[DNAME_INLINE_LEN]; 593 }; 594 void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); 595 void release_dentry_name_snapshot(struct name_snapshot *); 596 d_first_child(const struct dentry * dentry)597 static inline struct dentry *d_first_child(const struct dentry *dentry) 598 { 599 return hlist_entry_safe(dentry->d_children.first, struct dentry, d_sib); 600 } 601 d_next_sibling(const struct dentry * dentry)602 static inline struct dentry *d_next_sibling(const struct dentry *dentry) 603 { 604 return hlist_entry_safe(dentry->d_sib.next, struct dentry, d_sib); 605 } 606 607 #endif /* __LINUX_DCACHE_H */ 608