1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_RCULIST_H 3#define _LINUX_RCULIST_H 4 5#ifdef __KERNEL__ 6 7/* 8 * RCU-protected list version 9 */ 10#include <linux/list.h> 11#include <linux/rcupdate.h> 12 13/* 14 * Why is there no list_empty_rcu()? Because list_empty() serves this 15 * purpose. The list_empty() function fetches the RCU-protected pointer 16 * and compares it to the address of the list head, but neither dereferences 17 * this pointer itself nor provides this pointer to the caller. Therefore, 18 * it is not necessary to use rcu_dereference(), so that list_empty() can 19 * be used anywhere you would want to use a list_empty_rcu(). 20 */ 21 22/* 23 * INIT_LIST_HEAD_RCU - Initialize a list_head visible to RCU readers 24 * @list: list to be initialized 25 * 26 * You should instead use INIT_LIST_HEAD() for normal initialization and 27 * cleanup tasks, when readers have no access to the list being initialized. 28 * However, if the list being initialized is visible to readers, you 29 * need to keep the compiler from being too mischievous. 30 */ 31static inline void INIT_LIST_HEAD_RCU(struct list_head *list) 32{ 33 WRITE_ONCE(list->next, list); 34 WRITE_ONCE(list->prev, list); 35} 36 37/* 38 * return the ->next pointer of a list_head in an rcu safe 39 * way, we must not access it directly 40 */ 41#define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next))) 42 43/* 44 * Insert a new entry between two known consecutive entries. 45 * 46 * This is only for internal list manipulation where we know 47 * the prev/next entries already! 48 */ 49static inline void __list_add_rcu(struct list_head *new, 50 struct list_head *prev, struct list_head *next) 51{ 52 if (!__list_add_valid(new, prev, next)) 53 return; 54 55 new->next = next; 56 new->prev = prev; 57 rcu_assign_pointer(list_next_rcu(prev), new); 58 next->prev = new; 59} 60 61/** 62 * list_add_rcu - add a new entry to rcu-protected list 63 * @new: new entry to be added 64 * @head: list head to add it after 65 * 66 * Insert a new entry after the specified head. 67 * This is good for implementing stacks. 68 * 69 * The caller must take whatever precautions are necessary 70 * (such as holding appropriate locks) to avoid racing 71 * with another list-mutation primitive, such as list_add_rcu() 72 * or list_del_rcu(), running on this same list. 73 * However, it is perfectly legal to run concurrently with 74 * the _rcu list-traversal primitives, such as 75 * list_for_each_entry_rcu(). 76 */ 77static inline void list_add_rcu(struct list_head *new, struct list_head *head) 78{ 79 __list_add_rcu(new, head, head->next); 80} 81 82/** 83 * list_add_tail_rcu - add a new entry to rcu-protected list 84 * @new: new entry to be added 85 * @head: list head to add it before 86 * 87 * Insert a new entry before the specified head. 88 * This is useful for implementing queues. 89 * 90 * The caller must take whatever precautions are necessary 91 * (such as holding appropriate locks) to avoid racing 92 * with another list-mutation primitive, such as list_add_tail_rcu() 93 * or list_del_rcu(), running on this same list. 94 * However, it is perfectly legal to run concurrently with 95 * the _rcu list-traversal primitives, such as 96 * list_for_each_entry_rcu(). 97 */ 98static inline void list_add_tail_rcu(struct list_head *new, 99 struct list_head *head) 100{ 101 __list_add_rcu(new, head->prev, head); 102} 103 104/** 105 * list_del_rcu - deletes entry from list without re-initialization 106 * @entry: the element to delete from the list. 107 * 108 * Note: list_empty() on entry does not return true after this, 109 * the entry is in an undefined state. It is useful for RCU based 110 * lockfree traversal. 111 * 112 * In particular, it means that we can not poison the forward 113 * pointers that may still be used for walking the list. 114 * 115 * The caller must take whatever precautions are necessary 116 * (such as holding appropriate locks) to avoid racing 117 * with another list-mutation primitive, such as list_del_rcu() 118 * or list_add_rcu(), running on this same list. 119 * However, it is perfectly legal to run concurrently with 120 * the _rcu list-traversal primitives, such as 121 * list_for_each_entry_rcu(). 122 * 123 * Note that the caller is not permitted to immediately free 124 * the newly deleted entry. Instead, either synchronize_rcu() 125 * or call_rcu() must be used to defer freeing until an RCU 126 * grace period has elapsed. 127 */ 128static inline void list_del_rcu(struct list_head *entry) 129{ 130 __list_del_entry(entry); 131 entry->prev = LIST_POISON2; 132} 133 134/** 135 * hlist_del_init_rcu - deletes entry from hash list with re-initialization 136 * @n: the element to delete from the hash list. 137 * 138 * Note: list_unhashed() on the node return true after this. It is 139 * useful for RCU based read lockfree traversal if the writer side 140 * must know if the list entry is still hashed or already unhashed. 141 * 142 * In particular, it means that we can not poison the forward pointers 143 * that may still be used for walking the hash list and we can only 144 * zero the pprev pointer so list_unhashed() will return true after 145 * this. 146 * 147 * The caller must take whatever precautions are necessary (such as 148 * holding appropriate locks) to avoid racing with another 149 * list-mutation primitive, such as hlist_add_head_rcu() or 150 * hlist_del_rcu(), running on this same list. However, it is 151 * perfectly legal to run concurrently with the _rcu list-traversal 152 * primitives, such as hlist_for_each_entry_rcu(). 153 */ 154static inline void hlist_del_init_rcu(struct hlist_node *n) 155{ 156 if (!hlist_unhashed(n)) { 157 __hlist_del(n); 158 n->pprev = NULL; 159 } 160} 161 162/** 163 * list_replace_rcu - replace old entry by new one 164 * @old : the element to be replaced 165 * @new : the new element to insert 166 * 167 * The @old entry will be replaced with the @new entry atomically. 168 * Note: @old should not be empty. 169 */ 170static inline void list_replace_rcu(struct list_head *old, 171 struct list_head *new) 172{ 173 new->next = old->next; 174 new->prev = old->prev; 175 rcu_assign_pointer(list_next_rcu(new->prev), new); 176 new->next->prev = new; 177 old->prev = LIST_POISON2; 178} 179 180/** 181 * __list_splice_init_rcu - join an RCU-protected list into an existing list. 182 * @list: the RCU-protected list to splice 183 * @prev: points to the last element of the existing list 184 * @next: points to the first element of the existing list 185 * @sync: synchronize_rcu, synchronize_rcu_expedited, ... 186 * 187 * The list pointed to by @prev and @next can be RCU-read traversed 188 * concurrently with this function. 189 * 190 * Note that this function blocks. 191 * 192 * Important note: the caller must take whatever action is necessary to prevent 193 * any other updates to the existing list. In principle, it is possible to 194 * modify the list as soon as sync() begins execution. If this sort of thing 195 * becomes necessary, an alternative version based on call_rcu() could be 196 * created. But only if -really- needed -- there is no shortage of RCU API 197 * members. 198 */ 199static inline void __list_splice_init_rcu(struct list_head *list, 200 struct list_head *prev, 201 struct list_head *next, 202 void (*sync)(void)) 203{ 204 struct list_head *first = list->next; 205 struct list_head *last = list->prev; 206 207 /* 208 * "first" and "last" tracking list, so initialize it. RCU readers 209 * have access to this list, so we must use INIT_LIST_HEAD_RCU() 210 * instead of INIT_LIST_HEAD(). 211 */ 212 213 INIT_LIST_HEAD_RCU(list); 214 215 /* 216 * At this point, the list body still points to the source list. 217 * Wait for any readers to finish using the list before splicing 218 * the list body into the new list. Any new readers will see 219 * an empty list. 220 */ 221 222 sync(); 223 224 /* 225 * Readers are finished with the source list, so perform splice. 226 * The order is important if the new list is global and accessible 227 * to concurrent RCU readers. Note that RCU readers are not 228 * permitted to traverse the prev pointers without excluding 229 * this function. 230 */ 231 232 last->next = next; 233 rcu_assign_pointer(list_next_rcu(prev), first); 234 first->prev = prev; 235 next->prev = last; 236} 237 238/** 239 * list_splice_init_rcu - splice an RCU-protected list into an existing list, 240 * designed for stacks. 241 * @list: the RCU-protected list to splice 242 * @head: the place in the existing list to splice the first list into 243 * @sync: synchronize_rcu, synchronize_rcu_expedited, ... 244 */ 245static inline void list_splice_init_rcu(struct list_head *list, 246 struct list_head *head, 247 void (*sync)(void)) 248{ 249 if (!list_empty(list)) 250 __list_splice_init_rcu(list, head, head->next, sync); 251} 252 253/** 254 * list_splice_tail_init_rcu - splice an RCU-protected list into an existing 255 * list, designed for queues. 256 * @list: the RCU-protected list to splice 257 * @head: the place in the existing list to splice the first list into 258 * @sync: synchronize_rcu, synchronize_rcu_expedited, ... 259 */ 260static inline void list_splice_tail_init_rcu(struct list_head *list, 261 struct list_head *head, 262 void (*sync)(void)) 263{ 264 if (!list_empty(list)) 265 __list_splice_init_rcu(list, head->prev, head, sync); 266} 267 268/** 269 * list_entry_rcu - get the struct for this entry 270 * @ptr: the &struct list_head pointer. 271 * @type: the type of the struct this is embedded in. 272 * @member: the name of the list_head within the struct. 273 * 274 * This primitive may safely run concurrently with the _rcu list-mutation 275 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). 276 */ 277#define list_entry_rcu(ptr, type, member) \ 278 container_of(READ_ONCE(ptr), type, member) 279 280/* 281 * Where are list_empty_rcu() and list_first_entry_rcu()? 282 * 283 * Implementing those functions following their counterparts list_empty() and 284 * list_first_entry() is not advisable because they lead to subtle race 285 * conditions as the following snippet shows: 286 * 287 * if (!list_empty_rcu(mylist)) { 288 * struct foo *bar = list_first_entry_rcu(mylist, struct foo, list_member); 289 * do_something(bar); 290 * } 291 * 292 * The list may not be empty when list_empty_rcu checks it, but it may be when 293 * list_first_entry_rcu rereads the ->next pointer. 294 * 295 * Rereading the ->next pointer is not a problem for list_empty() and 296 * list_first_entry() because they would be protected by a lock that blocks 297 * writers. 298 * 299 * See list_first_or_null_rcu for an alternative. 300 */ 301 302/** 303 * list_first_or_null_rcu - get the first element from a list 304 * @ptr: the list head to take the element from. 305 * @type: the type of the struct this is embedded in. 306 * @member: the name of the list_head within the struct. 307 * 308 * Note that if the list is empty, it returns NULL. 309 * 310 * This primitive may safely run concurrently with the _rcu list-mutation 311 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). 312 */ 313#define list_first_or_null_rcu(ptr, type, member) \ 314({ \ 315 struct list_head *__ptr = (ptr); \ 316 struct list_head *__next = READ_ONCE(__ptr->next); \ 317 likely(__ptr != __next) ? list_entry_rcu(__next, type, member) : NULL; \ 318}) 319 320/** 321 * list_next_or_null_rcu - get the first element from a list 322 * @head: the head for the list. 323 * @ptr: the list head to take the next element from. 324 * @type: the type of the struct this is embedded in. 325 * @member: the name of the list_head within the struct. 326 * 327 * Note that if the ptr is at the end of the list, NULL is returned. 328 * 329 * This primitive may safely run concurrently with the _rcu list-mutation 330 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). 331 */ 332#define list_next_or_null_rcu(head, ptr, type, member) \ 333({ \ 334 struct list_head *__head = (head); \ 335 struct list_head *__ptr = (ptr); \ 336 struct list_head *__next = READ_ONCE(__ptr->next); \ 337 likely(__next != __head) ? list_entry_rcu(__next, type, \ 338 member) : NULL; \ 339}) 340 341/** 342 * list_for_each_entry_rcu - iterate over rcu list of given type 343 * @pos: the type * to use as a loop cursor. 344 * @head: the head for your list. 345 * @member: the name of the list_head within the struct. 346 * 347 * This list-traversal primitive may safely run concurrently with 348 * the _rcu list-mutation primitives such as list_add_rcu() 349 * as long as the traversal is guarded by rcu_read_lock(). 350 */ 351#define list_for_each_entry_rcu(pos, head, member) \ 352 for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \ 353 &pos->member != (head); \ 354 pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) 355 356/** 357 * list_entry_lockless - get the struct for this entry 358 * @ptr: the &struct list_head pointer. 359 * @type: the type of the struct this is embedded in. 360 * @member: the name of the list_head within the struct. 361 * 362 * This primitive may safely run concurrently with the _rcu 363 * list-mutation primitives such as list_add_rcu(), but requires some 364 * implicit RCU read-side guarding. One example is running within a special 365 * exception-time environment where preemption is disabled and where lockdep 366 * cannot be invoked. Another example is when items are added to the list, 367 * but never deleted. 368 */ 369#define list_entry_lockless(ptr, type, member) \ 370 container_of((typeof(ptr))READ_ONCE(ptr), type, member) 371 372/** 373 * list_for_each_entry_lockless - iterate over rcu list of given type 374 * @pos: the type * to use as a loop cursor. 375 * @head: the head for your list. 376 * @member: the name of the list_struct within the struct. 377 * 378 * This primitive may safely run concurrently with the _rcu 379 * list-mutation primitives such as list_add_rcu(), but requires some 380 * implicit RCU read-side guarding. One example is running within a special 381 * exception-time environment where preemption is disabled and where lockdep 382 * cannot be invoked. Another example is when items are added to the list, 383 * but never deleted. 384 */ 385#define list_for_each_entry_lockless(pos, head, member) \ 386 for (pos = list_entry_lockless((head)->next, typeof(*pos), member); \ 387 &pos->member != (head); \ 388 pos = list_entry_lockless(pos->member.next, typeof(*pos), member)) 389 390/** 391 * list_for_each_entry_continue_rcu - continue iteration over list of given type 392 * @pos: the type * to use as a loop cursor. 393 * @head: the head for your list. 394 * @member: the name of the list_head within the struct. 395 * 396 * Continue to iterate over list of given type, continuing after 397 * the current position which must have been in the list when the RCU read 398 * lock was taken. 399 * This would typically require either that you obtained the node from a 400 * previous walk of the list in the same RCU read-side critical section, or 401 * that you held some sort of non-RCU reference (such as a reference count) 402 * to keep the node alive *and* in the list. 403 * 404 * This iterator is similar to list_for_each_entry_from_rcu() except 405 * this starts after the given position and that one starts at the given 406 * position. 407 */ 408#define list_for_each_entry_continue_rcu(pos, head, member) \ 409 for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ 410 &pos->member != (head); \ 411 pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) 412 413/** 414 * list_for_each_entry_from_rcu - iterate over a list from current point 415 * @pos: the type * to use as a loop cursor. 416 * @head: the head for your list. 417 * @member: the name of the list_node within the struct. 418 * 419 * Iterate over the tail of a list starting from a given position, 420 * which must have been in the list when the RCU read lock was taken. 421 * This would typically require either that you obtained the node from a 422 * previous walk of the list in the same RCU read-side critical section, or 423 * that you held some sort of non-RCU reference (such as a reference count) 424 * to keep the node alive *and* in the list. 425 * 426 * This iterator is similar to list_for_each_entry_continue_rcu() except 427 * this starts from the given position and that one starts from the position 428 * after the given position. 429 */ 430#define list_for_each_entry_from_rcu(pos, head, member) \ 431 for (; &(pos)->member != (head); \ 432 pos = list_entry_rcu(pos->member.next, typeof(*(pos)), member)) 433 434/** 435 * hlist_del_rcu - deletes entry from hash list without re-initialization 436 * @n: the element to delete from the hash list. 437 * 438 * Note: list_unhashed() on entry does not return true after this, 439 * the entry is in an undefined state. It is useful for RCU based 440 * lockfree traversal. 441 * 442 * In particular, it means that we can not poison the forward 443 * pointers that may still be used for walking the hash list. 444 * 445 * The caller must take whatever precautions are necessary 446 * (such as holding appropriate locks) to avoid racing 447 * with another list-mutation primitive, such as hlist_add_head_rcu() 448 * or hlist_del_rcu(), running on this same list. 449 * However, it is perfectly legal to run concurrently with 450 * the _rcu list-traversal primitives, such as 451 * hlist_for_each_entry(). 452 */ 453static inline void hlist_del_rcu(struct hlist_node *n) 454{ 455 __hlist_del(n); 456 n->pprev = LIST_POISON2; 457} 458 459/** 460 * hlist_replace_rcu - replace old entry by new one 461 * @old : the element to be replaced 462 * @new : the new element to insert 463 * 464 * The @old entry will be replaced with the @new entry atomically. 465 */ 466static inline void hlist_replace_rcu(struct hlist_node *old, 467 struct hlist_node *new) 468{ 469 struct hlist_node *next = old->next; 470 471 new->next = next; 472 new->pprev = old->pprev; 473 rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new); 474 if (next) 475 new->next->pprev = &new->next; 476 old->pprev = LIST_POISON2; 477} 478 479/* 480 * return the first or the next element in an RCU protected hlist 481 */ 482#define hlist_first_rcu(head) (*((struct hlist_node __rcu **)(&(head)->first))) 483#define hlist_next_rcu(node) (*((struct hlist_node __rcu **)(&(node)->next))) 484#define hlist_pprev_rcu(node) (*((struct hlist_node __rcu **)((node)->pprev))) 485 486/** 487 * hlist_add_head_rcu 488 * @n: the element to add to the hash list. 489 * @h: the list to add to. 490 * 491 * Description: 492 * Adds the specified element to the specified hlist, 493 * while permitting racing traversals. 494 * 495 * The caller must take whatever precautions are necessary 496 * (such as holding appropriate locks) to avoid racing 497 * with another list-mutation primitive, such as hlist_add_head_rcu() 498 * or hlist_del_rcu(), running on this same list. 499 * However, it is perfectly legal to run concurrently with 500 * the _rcu list-traversal primitives, such as 501 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 502 * problems on Alpha CPUs. Regardless of the type of CPU, the 503 * list-traversal primitive must be guarded by rcu_read_lock(). 504 */ 505static inline void hlist_add_head_rcu(struct hlist_node *n, 506 struct hlist_head *h) 507{ 508 struct hlist_node *first = h->first; 509 510 n->next = first; 511 n->pprev = &h->first; 512 rcu_assign_pointer(hlist_first_rcu(h), n); 513 if (first) 514 first->pprev = &n->next; 515} 516 517/** 518 * hlist_add_tail_rcu 519 * @n: the element to add to the hash list. 520 * @h: the list to add to. 521 * 522 * Description: 523 * Adds the specified element to the specified hlist, 524 * while permitting racing traversals. 525 * 526 * The caller must take whatever precautions are necessary 527 * (such as holding appropriate locks) to avoid racing 528 * with another list-mutation primitive, such as hlist_add_head_rcu() 529 * or hlist_del_rcu(), running on this same list. 530 * However, it is perfectly legal to run concurrently with 531 * the _rcu list-traversal primitives, such as 532 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 533 * problems on Alpha CPUs. Regardless of the type of CPU, the 534 * list-traversal primitive must be guarded by rcu_read_lock(). 535 */ 536static inline void hlist_add_tail_rcu(struct hlist_node *n, 537 struct hlist_head *h) 538{ 539 struct hlist_node *i, *last = NULL; 540 541 /* Note: write side code, so rcu accessors are not needed. */ 542 for (i = h->first; i; i = i->next) 543 last = i; 544 545 if (last) { 546 n->next = last->next; 547 n->pprev = &last->next; 548 rcu_assign_pointer(hlist_next_rcu(last), n); 549 } else { 550 hlist_add_head_rcu(n, h); 551 } 552} 553 554/** 555 * hlist_add_before_rcu 556 * @n: the new element to add to the hash list. 557 * @next: the existing element to add the new element before. 558 * 559 * Description: 560 * Adds the specified element to the specified hlist 561 * before the specified node while permitting racing traversals. 562 * 563 * The caller must take whatever precautions are necessary 564 * (such as holding appropriate locks) to avoid racing 565 * with another list-mutation primitive, such as hlist_add_head_rcu() 566 * or hlist_del_rcu(), running on this same list. 567 * However, it is perfectly legal to run concurrently with 568 * the _rcu list-traversal primitives, such as 569 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 570 * problems on Alpha CPUs. 571 */ 572static inline void hlist_add_before_rcu(struct hlist_node *n, 573 struct hlist_node *next) 574{ 575 n->pprev = next->pprev; 576 n->next = next; 577 rcu_assign_pointer(hlist_pprev_rcu(n), n); 578 next->pprev = &n->next; 579} 580 581/** 582 * hlist_add_behind_rcu 583 * @n: the new element to add to the hash list. 584 * @prev: the existing element to add the new element after. 585 * 586 * Description: 587 * Adds the specified element to the specified hlist 588 * after the specified node while permitting racing traversals. 589 * 590 * The caller must take whatever precautions are necessary 591 * (such as holding appropriate locks) to avoid racing 592 * with another list-mutation primitive, such as hlist_add_head_rcu() 593 * or hlist_del_rcu(), running on this same list. 594 * However, it is perfectly legal to run concurrently with 595 * the _rcu list-traversal primitives, such as 596 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 597 * problems on Alpha CPUs. 598 */ 599static inline void hlist_add_behind_rcu(struct hlist_node *n, 600 struct hlist_node *prev) 601{ 602 n->next = prev->next; 603 n->pprev = &prev->next; 604 rcu_assign_pointer(hlist_next_rcu(prev), n); 605 if (n->next) 606 n->next->pprev = &n->next; 607} 608 609#define __hlist_for_each_rcu(pos, head) \ 610 for (pos = rcu_dereference(hlist_first_rcu(head)); \ 611 pos; \ 612 pos = rcu_dereference(hlist_next_rcu(pos))) 613 614/** 615 * hlist_for_each_entry_rcu - iterate over rcu list of given type 616 * @pos: the type * to use as a loop cursor. 617 * @head: the head for your list. 618 * @member: the name of the hlist_node within the struct. 619 * 620 * This list-traversal primitive may safely run concurrently with 621 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 622 * as long as the traversal is guarded by rcu_read_lock(). 623 */ 624#define hlist_for_each_entry_rcu(pos, head, member) \ 625 for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ 626 typeof(*(pos)), member); \ 627 pos; \ 628 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ 629 &(pos)->member)), typeof(*(pos)), member)) 630 631/** 632 * hlist_for_each_entry_rcu_notrace - iterate over rcu list of given type (for tracing) 633 * @pos: the type * to use as a loop cursor. 634 * @head: the head for your list. 635 * @member: the name of the hlist_node within the struct. 636 * 637 * This list-traversal primitive may safely run concurrently with 638 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 639 * as long as the traversal is guarded by rcu_read_lock(). 640 * 641 * This is the same as hlist_for_each_entry_rcu() except that it does 642 * not do any RCU debugging or tracing. 643 */ 644#define hlist_for_each_entry_rcu_notrace(pos, head, member) \ 645 for (pos = hlist_entry_safe (rcu_dereference_raw_notrace(hlist_first_rcu(head)),\ 646 typeof(*(pos)), member); \ 647 pos; \ 648 pos = hlist_entry_safe(rcu_dereference_raw_notrace(hlist_next_rcu(\ 649 &(pos)->member)), typeof(*(pos)), member)) 650 651/** 652 * hlist_for_each_entry_rcu_bh - iterate over rcu list of given type 653 * @pos: the type * to use as a loop cursor. 654 * @head: the head for your list. 655 * @member: the name of the hlist_node within the struct. 656 * 657 * This list-traversal primitive may safely run concurrently with 658 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 659 * as long as the traversal is guarded by rcu_read_lock(). 660 */ 661#define hlist_for_each_entry_rcu_bh(pos, head, member) \ 662 for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_first_rcu(head)),\ 663 typeof(*(pos)), member); \ 664 pos; \ 665 pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu(\ 666 &(pos)->member)), typeof(*(pos)), member)) 667 668/** 669 * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point 670 * @pos: the type * to use as a loop cursor. 671 * @member: the name of the hlist_node within the struct. 672 */ 673#define hlist_for_each_entry_continue_rcu(pos, member) \ 674 for (pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \ 675 &(pos)->member)), typeof(*(pos)), member); \ 676 pos; \ 677 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \ 678 &(pos)->member)), typeof(*(pos)), member)) 679 680/** 681 * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point 682 * @pos: the type * to use as a loop cursor. 683 * @member: the name of the hlist_node within the struct. 684 */ 685#define hlist_for_each_entry_continue_rcu_bh(pos, member) \ 686 for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \ 687 &(pos)->member)), typeof(*(pos)), member); \ 688 pos; \ 689 pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \ 690 &(pos)->member)), typeof(*(pos)), member)) 691 692/** 693 * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point 694 * @pos: the type * to use as a loop cursor. 695 * @member: the name of the hlist_node within the struct. 696 */ 697#define hlist_for_each_entry_from_rcu(pos, member) \ 698 for (; pos; \ 699 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \ 700 &(pos)->member)), typeof(*(pos)), member)) 701 702#endif /* __KERNEL__ */ 703#endif 704