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 */ 31 static 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 */ 49 static 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 */ 77 static 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 */ 98 static 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 */ 128 static 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 */ 154 static 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 */ 170 static 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: function to sync: synchronize_rcu(), synchronize_sched(), ... 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 */ 199 static 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: function to sync: synchronize_rcu(), synchronize_sched(), ... 244 */ 245 static 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: function to sync: synchronize_rcu(), synchronize_sched(), ... 259 */ 260 static 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 list-mutation 363 * primitives such as list_add_rcu(), but requires some implicit RCU 364 * read-side guarding. One example is running within a special 365 * exception-time environment where preemption is disabled and where 366 * lockdep cannot be invoked (in which case updaters must use RCU-sched, 367 * as in synchronize_sched(), call_rcu_sched(), and friends). Another 368 * example is when items are added to the list, but never deleted. 369 */ 370 #define list_entry_lockless(ptr, type, member) \ 371 container_of((typeof(ptr))READ_ONCE(ptr), type, member) 372 373 /** 374 * list_for_each_entry_lockless - iterate over rcu list of given type 375 * @pos: the type * to use as a loop cursor. 376 * @head: the head for your list. 377 * @member: the name of the list_struct within the struct. 378 * 379 * This primitive may safely run concurrently with the _rcu list-mutation 380 * primitives such as list_add_rcu(), but requires some implicit RCU 381 * read-side guarding. One example is running within a special 382 * exception-time environment where preemption is disabled and where 383 * lockdep cannot be invoked (in which case updaters must use RCU-sched, 384 * as in synchronize_sched(), call_rcu_sched(), and friends). Another 385 * example is when items are added to the list, but never deleted. 386 */ 387 #define list_for_each_entry_lockless(pos, head, member) \ 388 for (pos = list_entry_lockless((head)->next, typeof(*pos), member); \ 389 &pos->member != (head); \ 390 pos = list_entry_lockless(pos->member.next, typeof(*pos), member)) 391 392 /** 393 * list_for_each_entry_continue_rcu - continue iteration over list of given type 394 * @pos: the type * to use as a loop cursor. 395 * @head: the head for your list. 396 * @member: the name of the list_head within the struct. 397 * 398 * Continue to iterate over list of given type, continuing after 399 * the current position. 400 */ 401 #define list_for_each_entry_continue_rcu(pos, head, member) \ 402 for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ 403 &pos->member != (head); \ 404 pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) 405 406 /** 407 * hlist_del_rcu - deletes entry from hash list without re-initialization 408 * @n: the element to delete from the hash list. 409 * 410 * Note: list_unhashed() on entry does not return true after this, 411 * the entry is in an undefined state. It is useful for RCU based 412 * lockfree traversal. 413 * 414 * In particular, it means that we can not poison the forward 415 * pointers that may still be used for walking the hash list. 416 * 417 * The caller must take whatever precautions are necessary 418 * (such as holding appropriate locks) to avoid racing 419 * with another list-mutation primitive, such as hlist_add_head_rcu() 420 * or hlist_del_rcu(), running on this same list. 421 * However, it is perfectly legal to run concurrently with 422 * the _rcu list-traversal primitives, such as 423 * hlist_for_each_entry(). 424 */ 425 static inline void hlist_del_rcu(struct hlist_node *n) 426 { 427 __hlist_del(n); 428 n->pprev = LIST_POISON2; 429 } 430 431 /** 432 * hlist_replace_rcu - replace old entry by new one 433 * @old : the element to be replaced 434 * @new : the new element to insert 435 * 436 * The @old entry will be replaced with the @new entry atomically. 437 */ 438 static inline void hlist_replace_rcu(struct hlist_node *old, 439 struct hlist_node *new) 440 { 441 struct hlist_node *next = old->next; 442 443 new->next = next; 444 new->pprev = old->pprev; 445 rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new); 446 if (next) 447 new->next->pprev = &new->next; 448 old->pprev = LIST_POISON2; 449 } 450 451 /* 452 * return the first or the next element in an RCU protected hlist 453 */ 454 #define hlist_first_rcu(head) (*((struct hlist_node __rcu **)(&(head)->first))) 455 #define hlist_next_rcu(node) (*((struct hlist_node __rcu **)(&(node)->next))) 456 #define hlist_pprev_rcu(node) (*((struct hlist_node __rcu **)((node)->pprev))) 457 458 /** 459 * hlist_add_head_rcu 460 * @n: the element to add to the hash list. 461 * @h: the list to add to. 462 * 463 * Description: 464 * Adds the specified element to the specified hlist, 465 * while permitting racing traversals. 466 * 467 * The caller must take whatever precautions are necessary 468 * (such as holding appropriate locks) to avoid racing 469 * with another list-mutation primitive, such as hlist_add_head_rcu() 470 * or hlist_del_rcu(), running on this same list. 471 * However, it is perfectly legal to run concurrently with 472 * the _rcu list-traversal primitives, such as 473 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 474 * problems on Alpha CPUs. Regardless of the type of CPU, the 475 * list-traversal primitive must be guarded by rcu_read_lock(). 476 */ 477 static inline void hlist_add_head_rcu(struct hlist_node *n, 478 struct hlist_head *h) 479 { 480 struct hlist_node *first = h->first; 481 482 n->next = first; 483 n->pprev = &h->first; 484 rcu_assign_pointer(hlist_first_rcu(h), n); 485 if (first) 486 first->pprev = &n->next; 487 } 488 489 /** 490 * hlist_add_tail_rcu 491 * @n: the element to add to the hash list. 492 * @h: the list to add to. 493 * 494 * Description: 495 * Adds the specified element to the specified hlist, 496 * while permitting racing traversals. 497 * 498 * The caller must take whatever precautions are necessary 499 * (such as holding appropriate locks) to avoid racing 500 * with another list-mutation primitive, such as hlist_add_head_rcu() 501 * or hlist_del_rcu(), running on this same list. 502 * However, it is perfectly legal to run concurrently with 503 * the _rcu list-traversal primitives, such as 504 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 505 * problems on Alpha CPUs. Regardless of the type of CPU, the 506 * list-traversal primitive must be guarded by rcu_read_lock(). 507 */ 508 static inline void hlist_add_tail_rcu(struct hlist_node *n, 509 struct hlist_head *h) 510 { 511 struct hlist_node *i, *last = NULL; 512 513 /* Note: write side code, so rcu accessors are not needed. */ 514 for (i = h->first; i; i = i->next) 515 last = i; 516 517 if (last) { 518 n->next = last->next; 519 n->pprev = &last->next; 520 rcu_assign_pointer(hlist_next_rcu(last), n); 521 } else { 522 hlist_add_head_rcu(n, h); 523 } 524 } 525 526 /** 527 * hlist_add_before_rcu 528 * @n: the new element to add to the hash list. 529 * @next: the existing element to add the new element before. 530 * 531 * Description: 532 * Adds the specified element to the specified hlist 533 * before the specified node while permitting racing traversals. 534 * 535 * The caller must take whatever precautions are necessary 536 * (such as holding appropriate locks) to avoid racing 537 * with another list-mutation primitive, such as hlist_add_head_rcu() 538 * or hlist_del_rcu(), running on this same list. 539 * However, it is perfectly legal to run concurrently with 540 * the _rcu list-traversal primitives, such as 541 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 542 * problems on Alpha CPUs. 543 */ 544 static inline void hlist_add_before_rcu(struct hlist_node *n, 545 struct hlist_node *next) 546 { 547 n->pprev = next->pprev; 548 n->next = next; 549 rcu_assign_pointer(hlist_pprev_rcu(n), n); 550 next->pprev = &n->next; 551 } 552 553 /** 554 * hlist_add_behind_rcu 555 * @n: the new element to add to the hash list. 556 * @prev: the existing element to add the new element after. 557 * 558 * Description: 559 * Adds the specified element to the specified hlist 560 * after the specified node while permitting racing traversals. 561 * 562 * The caller must take whatever precautions are necessary 563 * (such as holding appropriate locks) to avoid racing 564 * with another list-mutation primitive, such as hlist_add_head_rcu() 565 * or hlist_del_rcu(), running on this same list. 566 * However, it is perfectly legal to run concurrently with 567 * the _rcu list-traversal primitives, such as 568 * hlist_for_each_entry_rcu(), used to prevent memory-consistency 569 * problems on Alpha CPUs. 570 */ 571 static inline void hlist_add_behind_rcu(struct hlist_node *n, 572 struct hlist_node *prev) 573 { 574 n->next = prev->next; 575 n->pprev = &prev->next; 576 rcu_assign_pointer(hlist_next_rcu(prev), n); 577 if (n->next) 578 n->next->pprev = &n->next; 579 } 580 581 #define __hlist_for_each_rcu(pos, head) \ 582 for (pos = rcu_dereference(hlist_first_rcu(head)); \ 583 pos; \ 584 pos = rcu_dereference(hlist_next_rcu(pos))) 585 586 /** 587 * hlist_for_each_entry_rcu - iterate over rcu list of given type 588 * @pos: the type * to use as a loop cursor. 589 * @head: the head for your list. 590 * @member: the name of the hlist_node within the struct. 591 * 592 * This list-traversal primitive may safely run concurrently with 593 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 594 * as long as the traversal is guarded by rcu_read_lock(). 595 */ 596 #define hlist_for_each_entry_rcu(pos, head, member) \ 597 for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\ 598 typeof(*(pos)), member); \ 599 pos; \ 600 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ 601 &(pos)->member)), typeof(*(pos)), member)) 602 603 /** 604 * hlist_for_each_entry_rcu_notrace - iterate over rcu list of given type (for tracing) 605 * @pos: the type * to use as a loop cursor. 606 * @head: the head for your list. 607 * @member: the name of the hlist_node within the struct. 608 * 609 * This list-traversal primitive may safely run concurrently with 610 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 611 * as long as the traversal is guarded by rcu_read_lock(). 612 * 613 * This is the same as hlist_for_each_entry_rcu() except that it does 614 * not do any RCU debugging or tracing. 615 */ 616 #define hlist_for_each_entry_rcu_notrace(pos, head, member) \ 617 for (pos = hlist_entry_safe (rcu_dereference_raw_notrace(hlist_first_rcu(head)),\ 618 typeof(*(pos)), member); \ 619 pos; \ 620 pos = hlist_entry_safe(rcu_dereference_raw_notrace(hlist_next_rcu(\ 621 &(pos)->member)), typeof(*(pos)), member)) 622 623 /** 624 * hlist_for_each_entry_rcu_bh - iterate over rcu list of given type 625 * @pos: the type * to use as a loop cursor. 626 * @head: the head for your list. 627 * @member: the name of the hlist_node within the struct. 628 * 629 * This list-traversal primitive may safely run concurrently with 630 * the _rcu list-mutation primitives such as hlist_add_head_rcu() 631 * as long as the traversal is guarded by rcu_read_lock(). 632 */ 633 #define hlist_for_each_entry_rcu_bh(pos, head, member) \ 634 for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_first_rcu(head)),\ 635 typeof(*(pos)), member); \ 636 pos; \ 637 pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu(\ 638 &(pos)->member)), typeof(*(pos)), member)) 639 640 /** 641 * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point 642 * @pos: the type * to use as a loop cursor. 643 * @member: the name of the hlist_node within the struct. 644 */ 645 #define hlist_for_each_entry_continue_rcu(pos, member) \ 646 for (pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \ 647 &(pos)->member)), typeof(*(pos)), member); \ 648 pos; \ 649 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \ 650 &(pos)->member)), typeof(*(pos)), member)) 651 652 /** 653 * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point 654 * @pos: the type * to use as a loop cursor. 655 * @member: the name of the hlist_node within the struct. 656 */ 657 #define hlist_for_each_entry_continue_rcu_bh(pos, member) \ 658 for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \ 659 &(pos)->member)), typeof(*(pos)), member); \ 660 pos; \ 661 pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \ 662 &(pos)->member)), typeof(*(pos)), member)) 663 664 /** 665 * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point 666 * @pos: the type * to use as a loop cursor. 667 * @member: the name of the hlist_node within the struct. 668 */ 669 #define hlist_for_each_entry_from_rcu(pos, member) \ 670 for (; pos; \ 671 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \ 672 &(pos)->member)), typeof(*(pos)), member)) 673 674 #endif /* __KERNEL__ */ 675 #endif 676