1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_WAIT_H 3 #define _LINUX_WAIT_H 4 /* 5 * Linux wait queue related types and methods 6 */ 7 #include <linux/list.h> 8 #include <linux/stddef.h> 9 #include <linux/spinlock.h> 10 11 #include <asm/current.h> 12 #include <uapi/linux/wait.h> 13 14 typedef struct wait_queue_entry wait_queue_entry_t; 15 16 typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); 17 int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); 18 19 /* wait_queue_entry::flags */ 20 #define WQ_FLAG_EXCLUSIVE 0x01 21 #define WQ_FLAG_WOKEN 0x02 22 #define WQ_FLAG_BOOKMARK 0x04 23 24 /* 25 * A single wait-queue entry structure: 26 */ 27 struct wait_queue_entry { 28 unsigned int flags; 29 void *private; 30 wait_queue_func_t func; 31 struct list_head entry; 32 }; 33 34 struct wait_queue_head { 35 spinlock_t lock; 36 struct list_head head; 37 }; 38 typedef struct wait_queue_head wait_queue_head_t; 39 40 struct task_struct; 41 42 /* 43 * Macros for declaration and initialisaton of the datatypes 44 */ 45 46 #define __WAITQUEUE_INITIALIZER(name, tsk) { \ 47 .private = tsk, \ 48 .func = default_wake_function, \ 49 .entry = { NULL, NULL } } 50 51 #define DECLARE_WAITQUEUE(name, tsk) \ 52 struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk) 53 54 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ 55 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ 56 .head = { &(name).head, &(name).head } } 57 58 #define DECLARE_WAIT_QUEUE_HEAD(name) \ 59 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name) 60 61 extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *); 62 63 #define init_waitqueue_head(wq_head) \ 64 do { \ 65 static struct lock_class_key __key; \ 66 \ 67 __init_waitqueue_head((wq_head), #wq_head, &__key); \ 68 } while (0) 69 70 #ifdef CONFIG_LOCKDEP 71 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \ 72 ({ init_waitqueue_head(&name); name; }) 73 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \ 74 struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) 75 #else 76 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) 77 #endif 78 79 static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p) 80 { 81 wq_entry->flags = 0; 82 wq_entry->private = p; 83 wq_entry->func = default_wake_function; 84 } 85 86 static inline void 87 init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func) 88 { 89 wq_entry->flags = 0; 90 wq_entry->private = NULL; 91 wq_entry->func = func; 92 } 93 94 /** 95 * waitqueue_active -- locklessly test for waiters on the queue 96 * @wq_head: the waitqueue to test for waiters 97 * 98 * returns true if the wait list is not empty 99 * 100 * NOTE: this function is lockless and requires care, incorrect usage _will_ 101 * lead to sporadic and non-obvious failure. 102 * 103 * Use either while holding wait_queue_head::lock or when used for wakeups 104 * with an extra smp_mb() like: 105 * 106 * CPU0 - waker CPU1 - waiter 107 * 108 * for (;;) { 109 * @cond = true; prepare_to_wait(&wq_head, &wait, state); 110 * smp_mb(); // smp_mb() from set_current_state() 111 * if (waitqueue_active(wq_head)) if (@cond) 112 * wake_up(wq_head); break; 113 * schedule(); 114 * } 115 * finish_wait(&wq_head, &wait); 116 * 117 * Because without the explicit smp_mb() it's possible for the 118 * waitqueue_active() load to get hoisted over the @cond store such that we'll 119 * observe an empty wait list while the waiter might not observe @cond. 120 * 121 * Also note that this 'optimization' trades a spin_lock() for an smp_mb(), 122 * which (when the lock is uncontended) are of roughly equal cost. 123 */ 124 static inline int waitqueue_active(struct wait_queue_head *wq_head) 125 { 126 return !list_empty(&wq_head->head); 127 } 128 129 /** 130 * wq_has_sleeper - check if there are any waiting processes 131 * @wq_head: wait queue head 132 * 133 * Returns true if wq_head has waiting processes 134 * 135 * Please refer to the comment for waitqueue_active. 136 */ 137 static inline bool wq_has_sleeper(struct wait_queue_head *wq_head) 138 { 139 /* 140 * We need to be sure we are in sync with the 141 * add_wait_queue modifications to the wait queue. 142 * 143 * This memory barrier should be paired with one on the 144 * waiting side. 145 */ 146 smp_mb(); 147 return waitqueue_active(wq_head); 148 } 149 150 extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); 151 extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); 152 extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); 153 154 static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) 155 { 156 list_add(&wq_entry->entry, &wq_head->head); 157 } 158 159 /* 160 * Used for wake-one threads: 161 */ 162 static inline void 163 __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) 164 { 165 wq_entry->flags |= WQ_FLAG_EXCLUSIVE; 166 __add_wait_queue(wq_head, wq_entry); 167 } 168 169 static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) 170 { 171 list_add_tail(&wq_entry->entry, &wq_head->head); 172 } 173 174 static inline void 175 __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) 176 { 177 wq_entry->flags |= WQ_FLAG_EXCLUSIVE; 178 __add_wait_queue_entry_tail(wq_head, wq_entry); 179 } 180 181 static inline void 182 __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) 183 { 184 list_del(&wq_entry->entry); 185 } 186 187 void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); 188 void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); 189 void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head, 190 unsigned int mode, void *key, wait_queue_entry_t *bookmark); 191 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); 192 void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr); 193 void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr); 194 195 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) 196 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) 197 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) 198 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1) 199 #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0) 200 201 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) 202 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL) 203 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL) 204 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1) 205 206 /* 207 * Wakeup macros to be used to report events to the targets. 208 */ 209 #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m)) 210 #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m)) 211 #define wake_up_poll(x, m) \ 212 __wake_up(x, TASK_NORMAL, 1, poll_to_key(m)) 213 #define wake_up_locked_poll(x, m) \ 214 __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m)) 215 #define wake_up_interruptible_poll(x, m) \ 216 __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m)) 217 #define wake_up_interruptible_sync_poll(x, m) \ 218 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, poll_to_key(m)) 219 220 #define ___wait_cond_timeout(condition) \ 221 ({ \ 222 bool __cond = (condition); \ 223 if (__cond && !__ret) \ 224 __ret = 1; \ 225 __cond || !__ret; \ 226 }) 227 228 #define ___wait_is_interruptible(state) \ 229 (!__builtin_constant_p(state) || \ 230 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \ 231 232 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags); 233 234 /* 235 * The below macro ___wait_event() has an explicit shadow of the __ret 236 * variable when used from the wait_event_*() macros. 237 * 238 * This is so that both can use the ___wait_cond_timeout() construct 239 * to wrap the condition. 240 * 241 * The type inconsistency of the wait_event_*() __ret variable is also 242 * on purpose; we use long where we can return timeout values and int 243 * otherwise. 244 */ 245 246 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd) \ 247 ({ \ 248 __label__ __out; \ 249 struct wait_queue_entry __wq_entry; \ 250 long __ret = ret; /* explicit shadow */ \ 251 \ 252 init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ 253 for (;;) { \ 254 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\ 255 \ 256 if (condition) \ 257 break; \ 258 \ 259 if (___wait_is_interruptible(state) && __int) { \ 260 __ret = __int; \ 261 goto __out; \ 262 } \ 263 \ 264 cmd; \ 265 } \ 266 finish_wait(&wq_head, &__wq_entry); \ 267 __out: __ret; \ 268 }) 269 270 #define __wait_event(wq_head, condition) \ 271 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 272 schedule()) 273 274 /** 275 * wait_event - sleep until a condition gets true 276 * @wq_head: the waitqueue to wait on 277 * @condition: a C expression for the event to wait for 278 * 279 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 280 * @condition evaluates to true. The @condition is checked each time 281 * the waitqueue @wq_head is woken up. 282 * 283 * wake_up() has to be called after changing any variable that could 284 * change the result of the wait condition. 285 */ 286 #define wait_event(wq_head, condition) \ 287 do { \ 288 might_sleep(); \ 289 if (condition) \ 290 break; \ 291 __wait_event(wq_head, condition); \ 292 } while (0) 293 294 #define __io_wait_event(wq_head, condition) \ 295 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 296 io_schedule()) 297 298 /* 299 * io_wait_event() -- like wait_event() but with io_schedule() 300 */ 301 #define io_wait_event(wq_head, condition) \ 302 do { \ 303 might_sleep(); \ 304 if (condition) \ 305 break; \ 306 __io_wait_event(wq_head, condition); \ 307 } while (0) 308 309 #define __wait_event_freezable(wq_head, condition) \ 310 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \ 311 schedule(); try_to_freeze()) 312 313 /** 314 * wait_event_freezable - sleep (or freeze) until a condition gets true 315 * @wq_head: the waitqueue to wait on 316 * @condition: a C expression for the event to wait for 317 * 318 * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute 319 * to system load) until the @condition evaluates to true. The 320 * @condition is checked each time the waitqueue @wq_head is woken up. 321 * 322 * wake_up() has to be called after changing any variable that could 323 * change the result of the wait condition. 324 */ 325 #define wait_event_freezable(wq_head, condition) \ 326 ({ \ 327 int __ret = 0; \ 328 might_sleep(); \ 329 if (!(condition)) \ 330 __ret = __wait_event_freezable(wq_head, condition); \ 331 __ret; \ 332 }) 333 334 #define __wait_event_timeout(wq_head, condition, timeout) \ 335 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 336 TASK_UNINTERRUPTIBLE, 0, timeout, \ 337 __ret = schedule_timeout(__ret)) 338 339 /** 340 * wait_event_timeout - sleep until a condition gets true or a timeout elapses 341 * @wq_head: the waitqueue to wait on 342 * @condition: a C expression for the event to wait for 343 * @timeout: timeout, in jiffies 344 * 345 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 346 * @condition evaluates to true. The @condition is checked each time 347 * the waitqueue @wq_head is woken up. 348 * 349 * wake_up() has to be called after changing any variable that could 350 * change the result of the wait condition. 351 * 352 * Returns: 353 * 0 if the @condition evaluated to %false after the @timeout elapsed, 354 * 1 if the @condition evaluated to %true after the @timeout elapsed, 355 * or the remaining jiffies (at least 1) if the @condition evaluated 356 * to %true before the @timeout elapsed. 357 */ 358 #define wait_event_timeout(wq_head, condition, timeout) \ 359 ({ \ 360 long __ret = timeout; \ 361 might_sleep(); \ 362 if (!___wait_cond_timeout(condition)) \ 363 __ret = __wait_event_timeout(wq_head, condition, timeout); \ 364 __ret; \ 365 }) 366 367 #define __wait_event_freezable_timeout(wq_head, condition, timeout) \ 368 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 369 TASK_INTERRUPTIBLE, 0, timeout, \ 370 __ret = schedule_timeout(__ret); try_to_freeze()) 371 372 /* 373 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid 374 * increasing load and is freezable. 375 */ 376 #define wait_event_freezable_timeout(wq_head, condition, timeout) \ 377 ({ \ 378 long __ret = timeout; \ 379 might_sleep(); \ 380 if (!___wait_cond_timeout(condition)) \ 381 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \ 382 __ret; \ 383 }) 384 385 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \ 386 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0, \ 387 cmd1; schedule(); cmd2) 388 /* 389 * Just like wait_event_cmd(), except it sets exclusive flag 390 */ 391 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \ 392 do { \ 393 if (condition) \ 394 break; \ 395 __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2); \ 396 } while (0) 397 398 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2) \ 399 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 400 cmd1; schedule(); cmd2) 401 402 /** 403 * wait_event_cmd - sleep until a condition gets true 404 * @wq_head: the waitqueue to wait on 405 * @condition: a C expression for the event to wait for 406 * @cmd1: the command will be executed before sleep 407 * @cmd2: the command will be executed after sleep 408 * 409 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 410 * @condition evaluates to true. The @condition is checked each time 411 * the waitqueue @wq_head is woken up. 412 * 413 * wake_up() has to be called after changing any variable that could 414 * change the result of the wait condition. 415 */ 416 #define wait_event_cmd(wq_head, condition, cmd1, cmd2) \ 417 do { \ 418 if (condition) \ 419 break; \ 420 __wait_event_cmd(wq_head, condition, cmd1, cmd2); \ 421 } while (0) 422 423 #define __wait_event_interruptible(wq_head, condition) \ 424 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \ 425 schedule()) 426 427 /** 428 * wait_event_interruptible - sleep until a condition gets true 429 * @wq_head: the waitqueue to wait on 430 * @condition: a C expression for the event to wait for 431 * 432 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 433 * @condition evaluates to true or a signal is received. 434 * The @condition is checked each time the waitqueue @wq_head is woken up. 435 * 436 * wake_up() has to be called after changing any variable that could 437 * change the result of the wait condition. 438 * 439 * The function will return -ERESTARTSYS if it was interrupted by a 440 * signal and 0 if @condition evaluated to true. 441 */ 442 #define wait_event_interruptible(wq_head, condition) \ 443 ({ \ 444 int __ret = 0; \ 445 might_sleep(); \ 446 if (!(condition)) \ 447 __ret = __wait_event_interruptible(wq_head, condition); \ 448 __ret; \ 449 }) 450 451 #define __wait_event_interruptible_timeout(wq_head, condition, timeout) \ 452 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 453 TASK_INTERRUPTIBLE, 0, timeout, \ 454 __ret = schedule_timeout(__ret)) 455 456 /** 457 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses 458 * @wq_head: the waitqueue to wait on 459 * @condition: a C expression for the event to wait for 460 * @timeout: timeout, in jiffies 461 * 462 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 463 * @condition evaluates to true or a signal is received. 464 * The @condition is checked each time the waitqueue @wq_head is woken up. 465 * 466 * wake_up() has to be called after changing any variable that could 467 * change the result of the wait condition. 468 * 469 * Returns: 470 * 0 if the @condition evaluated to %false after the @timeout elapsed, 471 * 1 if the @condition evaluated to %true after the @timeout elapsed, 472 * the remaining jiffies (at least 1) if the @condition evaluated 473 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was 474 * interrupted by a signal. 475 */ 476 #define wait_event_interruptible_timeout(wq_head, condition, timeout) \ 477 ({ \ 478 long __ret = timeout; \ 479 might_sleep(); \ 480 if (!___wait_cond_timeout(condition)) \ 481 __ret = __wait_event_interruptible_timeout(wq_head, \ 482 condition, timeout); \ 483 __ret; \ 484 }) 485 486 #define __wait_event_hrtimeout(wq_head, condition, timeout, state) \ 487 ({ \ 488 int __ret = 0; \ 489 struct hrtimer_sleeper __t; \ 490 \ 491 hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); \ 492 hrtimer_init_sleeper(&__t, current); \ 493 if ((timeout) != KTIME_MAX) \ 494 hrtimer_start_range_ns(&__t.timer, timeout, \ 495 current->timer_slack_ns, \ 496 HRTIMER_MODE_REL); \ 497 \ 498 __ret = ___wait_event(wq_head, condition, state, 0, 0, \ 499 if (!__t.task) { \ 500 __ret = -ETIME; \ 501 break; \ 502 } \ 503 schedule()); \ 504 \ 505 hrtimer_cancel(&__t.timer); \ 506 destroy_hrtimer_on_stack(&__t.timer); \ 507 __ret; \ 508 }) 509 510 /** 511 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses 512 * @wq_head: the waitqueue to wait on 513 * @condition: a C expression for the event to wait for 514 * @timeout: timeout, as a ktime_t 515 * 516 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 517 * @condition evaluates to true or a signal is received. 518 * The @condition is checked each time the waitqueue @wq_head is woken up. 519 * 520 * wake_up() has to be called after changing any variable that could 521 * change the result of the wait condition. 522 * 523 * The function returns 0 if @condition became true, or -ETIME if the timeout 524 * elapsed. 525 */ 526 #define wait_event_hrtimeout(wq_head, condition, timeout) \ 527 ({ \ 528 int __ret = 0; \ 529 might_sleep(); \ 530 if (!(condition)) \ 531 __ret = __wait_event_hrtimeout(wq_head, condition, timeout, \ 532 TASK_UNINTERRUPTIBLE); \ 533 __ret; \ 534 }) 535 536 /** 537 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses 538 * @wq: the waitqueue to wait on 539 * @condition: a C expression for the event to wait for 540 * @timeout: timeout, as a ktime_t 541 * 542 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 543 * @condition evaluates to true or a signal is received. 544 * The @condition is checked each time the waitqueue @wq is woken up. 545 * 546 * wake_up() has to be called after changing any variable that could 547 * change the result of the wait condition. 548 * 549 * The function returns 0 if @condition became true, -ERESTARTSYS if it was 550 * interrupted by a signal, or -ETIME if the timeout elapsed. 551 */ 552 #define wait_event_interruptible_hrtimeout(wq, condition, timeout) \ 553 ({ \ 554 long __ret = 0; \ 555 might_sleep(); \ 556 if (!(condition)) \ 557 __ret = __wait_event_hrtimeout(wq, condition, timeout, \ 558 TASK_INTERRUPTIBLE); \ 559 __ret; \ 560 }) 561 562 #define __wait_event_interruptible_exclusive(wq, condition) \ 563 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \ 564 schedule()) 565 566 #define wait_event_interruptible_exclusive(wq, condition) \ 567 ({ \ 568 int __ret = 0; \ 569 might_sleep(); \ 570 if (!(condition)) \ 571 __ret = __wait_event_interruptible_exclusive(wq, condition); \ 572 __ret; \ 573 }) 574 575 #define __wait_event_killable_exclusive(wq, condition) \ 576 ___wait_event(wq, condition, TASK_KILLABLE, 1, 0, \ 577 schedule()) 578 579 #define wait_event_killable_exclusive(wq, condition) \ 580 ({ \ 581 int __ret = 0; \ 582 might_sleep(); \ 583 if (!(condition)) \ 584 __ret = __wait_event_killable_exclusive(wq, condition); \ 585 __ret; \ 586 }) 587 588 589 #define __wait_event_freezable_exclusive(wq, condition) \ 590 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \ 591 schedule(); try_to_freeze()) 592 593 #define wait_event_freezable_exclusive(wq, condition) \ 594 ({ \ 595 int __ret = 0; \ 596 might_sleep(); \ 597 if (!(condition)) \ 598 __ret = __wait_event_freezable_exclusive(wq, condition); \ 599 __ret; \ 600 }) 601 602 /** 603 * wait_event_idle - wait for a condition without contributing to system load 604 * @wq_head: the waitqueue to wait on 605 * @condition: a C expression for the event to wait for 606 * 607 * The process is put to sleep (TASK_IDLE) until the 608 * @condition evaluates to true. 609 * The @condition is checked each time the waitqueue @wq_head is woken up. 610 * 611 * wake_up() has to be called after changing any variable that could 612 * change the result of the wait condition. 613 * 614 */ 615 #define wait_event_idle(wq_head, condition) \ 616 do { \ 617 might_sleep(); \ 618 if (!(condition)) \ 619 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \ 620 } while (0) 621 622 /** 623 * wait_event_idle_exclusive - wait for a condition with contributing to system load 624 * @wq_head: the waitqueue to wait on 625 * @condition: a C expression for the event to wait for 626 * 627 * The process is put to sleep (TASK_IDLE) until the 628 * @condition evaluates to true. 629 * The @condition is checked each time the waitqueue @wq_head is woken up. 630 * 631 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag 632 * set thus if other processes wait on the same list, when this 633 * process is woken further processes are not considered. 634 * 635 * wake_up() has to be called after changing any variable that could 636 * change the result of the wait condition. 637 * 638 */ 639 #define wait_event_idle_exclusive(wq_head, condition) \ 640 do { \ 641 might_sleep(); \ 642 if (!(condition)) \ 643 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \ 644 } while (0) 645 646 #define __wait_event_idle_timeout(wq_head, condition, timeout) \ 647 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 648 TASK_IDLE, 0, timeout, \ 649 __ret = schedule_timeout(__ret)) 650 651 /** 652 * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses 653 * @wq_head: the waitqueue to wait on 654 * @condition: a C expression for the event to wait for 655 * @timeout: timeout, in jiffies 656 * 657 * The process is put to sleep (TASK_IDLE) until the 658 * @condition evaluates to true. The @condition is checked each time 659 * the waitqueue @wq_head is woken up. 660 * 661 * wake_up() has to be called after changing any variable that could 662 * change the result of the wait condition. 663 * 664 * Returns: 665 * 0 if the @condition evaluated to %false after the @timeout elapsed, 666 * 1 if the @condition evaluated to %true after the @timeout elapsed, 667 * or the remaining jiffies (at least 1) if the @condition evaluated 668 * to %true before the @timeout elapsed. 669 */ 670 #define wait_event_idle_timeout(wq_head, condition, timeout) \ 671 ({ \ 672 long __ret = timeout; \ 673 might_sleep(); \ 674 if (!___wait_cond_timeout(condition)) \ 675 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \ 676 __ret; \ 677 }) 678 679 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \ 680 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 681 TASK_IDLE, 1, timeout, \ 682 __ret = schedule_timeout(__ret)) 683 684 /** 685 * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses 686 * @wq_head: the waitqueue to wait on 687 * @condition: a C expression for the event to wait for 688 * @timeout: timeout, in jiffies 689 * 690 * The process is put to sleep (TASK_IDLE) until the 691 * @condition evaluates to true. The @condition is checked each time 692 * the waitqueue @wq_head is woken up. 693 * 694 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag 695 * set thus if other processes wait on the same list, when this 696 * process is woken further processes are not considered. 697 * 698 * wake_up() has to be called after changing any variable that could 699 * change the result of the wait condition. 700 * 701 * Returns: 702 * 0 if the @condition evaluated to %false after the @timeout elapsed, 703 * 1 if the @condition evaluated to %true after the @timeout elapsed, 704 * or the remaining jiffies (at least 1) if the @condition evaluated 705 * to %true before the @timeout elapsed. 706 */ 707 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \ 708 ({ \ 709 long __ret = timeout; \ 710 might_sleep(); \ 711 if (!___wait_cond_timeout(condition)) \ 712 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\ 713 __ret; \ 714 }) 715 716 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *); 717 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *); 718 719 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \ 720 ({ \ 721 int __ret; \ 722 DEFINE_WAIT(__wait); \ 723 if (exclusive) \ 724 __wait.flags |= WQ_FLAG_EXCLUSIVE; \ 725 do { \ 726 __ret = fn(&(wq), &__wait); \ 727 if (__ret) \ 728 break; \ 729 } while (!(condition)); \ 730 __remove_wait_queue(&(wq), &__wait); \ 731 __set_current_state(TASK_RUNNING); \ 732 __ret; \ 733 }) 734 735 736 /** 737 * wait_event_interruptible_locked - sleep until a condition gets true 738 * @wq: the waitqueue to wait on 739 * @condition: a C expression for the event to wait for 740 * 741 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 742 * @condition evaluates to true or a signal is received. 743 * The @condition is checked each time the waitqueue @wq is woken up. 744 * 745 * It must be called with wq.lock being held. This spinlock is 746 * unlocked while sleeping but @condition testing is done while lock 747 * is held and when this macro exits the lock is held. 748 * 749 * The lock is locked/unlocked using spin_lock()/spin_unlock() 750 * functions which must match the way they are locked/unlocked outside 751 * of this macro. 752 * 753 * wake_up_locked() has to be called after changing any variable that could 754 * change the result of the wait condition. 755 * 756 * The function will return -ERESTARTSYS if it was interrupted by a 757 * signal and 0 if @condition evaluated to true. 758 */ 759 #define wait_event_interruptible_locked(wq, condition) \ 760 ((condition) \ 761 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr)) 762 763 /** 764 * wait_event_interruptible_locked_irq - sleep until a condition gets true 765 * @wq: the waitqueue to wait on 766 * @condition: a C expression for the event to wait for 767 * 768 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 769 * @condition evaluates to true or a signal is received. 770 * The @condition is checked each time the waitqueue @wq is woken up. 771 * 772 * It must be called with wq.lock being held. This spinlock is 773 * unlocked while sleeping but @condition testing is done while lock 774 * is held and when this macro exits the lock is held. 775 * 776 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq() 777 * functions which must match the way they are locked/unlocked outside 778 * of this macro. 779 * 780 * wake_up_locked() has to be called after changing any variable that could 781 * change the result of the wait condition. 782 * 783 * The function will return -ERESTARTSYS if it was interrupted by a 784 * signal and 0 if @condition evaluated to true. 785 */ 786 #define wait_event_interruptible_locked_irq(wq, condition) \ 787 ((condition) \ 788 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq)) 789 790 /** 791 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true 792 * @wq: the waitqueue to wait on 793 * @condition: a C expression for the event to wait for 794 * 795 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 796 * @condition evaluates to true or a signal is received. 797 * The @condition is checked each time the waitqueue @wq is woken up. 798 * 799 * It must be called with wq.lock being held. This spinlock is 800 * unlocked while sleeping but @condition testing is done while lock 801 * is held and when this macro exits the lock is held. 802 * 803 * The lock is locked/unlocked using spin_lock()/spin_unlock() 804 * functions which must match the way they are locked/unlocked outside 805 * of this macro. 806 * 807 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag 808 * set thus when other process waits process on the list if this 809 * process is awaken further processes are not considered. 810 * 811 * wake_up_locked() has to be called after changing any variable that could 812 * change the result of the wait condition. 813 * 814 * The function will return -ERESTARTSYS if it was interrupted by a 815 * signal and 0 if @condition evaluated to true. 816 */ 817 #define wait_event_interruptible_exclusive_locked(wq, condition) \ 818 ((condition) \ 819 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr)) 820 821 /** 822 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true 823 * @wq: the waitqueue to wait on 824 * @condition: a C expression for the event to wait for 825 * 826 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 827 * @condition evaluates to true or a signal is received. 828 * The @condition is checked each time the waitqueue @wq is woken up. 829 * 830 * It must be called with wq.lock being held. This spinlock is 831 * unlocked while sleeping but @condition testing is done while lock 832 * is held and when this macro exits the lock is held. 833 * 834 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq() 835 * functions which must match the way they are locked/unlocked outside 836 * of this macro. 837 * 838 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag 839 * set thus when other process waits process on the list if this 840 * process is awaken further processes are not considered. 841 * 842 * wake_up_locked() has to be called after changing any variable that could 843 * change the result of the wait condition. 844 * 845 * The function will return -ERESTARTSYS if it was interrupted by a 846 * signal and 0 if @condition evaluated to true. 847 */ 848 #define wait_event_interruptible_exclusive_locked_irq(wq, condition) \ 849 ((condition) \ 850 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq)) 851 852 853 #define __wait_event_killable(wq, condition) \ 854 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule()) 855 856 /** 857 * wait_event_killable - sleep until a condition gets true 858 * @wq_head: the waitqueue to wait on 859 * @condition: a C expression for the event to wait for 860 * 861 * The process is put to sleep (TASK_KILLABLE) until the 862 * @condition evaluates to true or a signal is received. 863 * The @condition is checked each time the waitqueue @wq_head is woken up. 864 * 865 * wake_up() has to be called after changing any variable that could 866 * change the result of the wait condition. 867 * 868 * The function will return -ERESTARTSYS if it was interrupted by a 869 * signal and 0 if @condition evaluated to true. 870 */ 871 #define wait_event_killable(wq_head, condition) \ 872 ({ \ 873 int __ret = 0; \ 874 might_sleep(); \ 875 if (!(condition)) \ 876 __ret = __wait_event_killable(wq_head, condition); \ 877 __ret; \ 878 }) 879 880 #define __wait_event_killable_timeout(wq_head, condition, timeout) \ 881 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 882 TASK_KILLABLE, 0, timeout, \ 883 __ret = schedule_timeout(__ret)) 884 885 /** 886 * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses 887 * @wq_head: the waitqueue to wait on 888 * @condition: a C expression for the event to wait for 889 * @timeout: timeout, in jiffies 890 * 891 * The process is put to sleep (TASK_KILLABLE) until the 892 * @condition evaluates to true or a kill signal is received. 893 * The @condition is checked each time the waitqueue @wq_head is woken up. 894 * 895 * wake_up() has to be called after changing any variable that could 896 * change the result of the wait condition. 897 * 898 * Returns: 899 * 0 if the @condition evaluated to %false after the @timeout elapsed, 900 * 1 if the @condition evaluated to %true after the @timeout elapsed, 901 * the remaining jiffies (at least 1) if the @condition evaluated 902 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was 903 * interrupted by a kill signal. 904 * 905 * Only kill signals interrupt this process. 906 */ 907 #define wait_event_killable_timeout(wq_head, condition, timeout) \ 908 ({ \ 909 long __ret = timeout; \ 910 might_sleep(); \ 911 if (!___wait_cond_timeout(condition)) \ 912 __ret = __wait_event_killable_timeout(wq_head, \ 913 condition, timeout); \ 914 __ret; \ 915 }) 916 917 918 #define __wait_event_lock_irq(wq_head, condition, lock, cmd) \ 919 (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 920 spin_unlock_irq(&lock); \ 921 cmd; \ 922 schedule(); \ 923 spin_lock_irq(&lock)) 924 925 /** 926 * wait_event_lock_irq_cmd - sleep until a condition gets true. The 927 * condition is checked under the lock. This 928 * is expected to be called with the lock 929 * taken. 930 * @wq_head: the waitqueue to wait on 931 * @condition: a C expression for the event to wait for 932 * @lock: a locked spinlock_t, which will be released before cmd 933 * and schedule() and reacquired afterwards. 934 * @cmd: a command which is invoked outside the critical section before 935 * sleep 936 * 937 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 938 * @condition evaluates to true. The @condition is checked each time 939 * the waitqueue @wq_head is woken up. 940 * 941 * wake_up() has to be called after changing any variable that could 942 * change the result of the wait condition. 943 * 944 * This is supposed to be called while holding the lock. The lock is 945 * dropped before invoking the cmd and going to sleep and is reacquired 946 * afterwards. 947 */ 948 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd) \ 949 do { \ 950 if (condition) \ 951 break; \ 952 __wait_event_lock_irq(wq_head, condition, lock, cmd); \ 953 } while (0) 954 955 /** 956 * wait_event_lock_irq - sleep until a condition gets true. The 957 * condition is checked under the lock. This 958 * is expected to be called with the lock 959 * taken. 960 * @wq_head: the waitqueue to wait on 961 * @condition: a C expression for the event to wait for 962 * @lock: a locked spinlock_t, which will be released before schedule() 963 * and reacquired afterwards. 964 * 965 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 966 * @condition evaluates to true. The @condition is checked each time 967 * the waitqueue @wq_head is woken up. 968 * 969 * wake_up() has to be called after changing any variable that could 970 * change the result of the wait condition. 971 * 972 * This is supposed to be called while holding the lock. The lock is 973 * dropped before going to sleep and is reacquired afterwards. 974 */ 975 #define wait_event_lock_irq(wq_head, condition, lock) \ 976 do { \ 977 if (condition) \ 978 break; \ 979 __wait_event_lock_irq(wq_head, condition, lock, ); \ 980 } while (0) 981 982 983 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd) \ 984 ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \ 985 spin_unlock_irq(&lock); \ 986 cmd; \ 987 schedule(); \ 988 spin_lock_irq(&lock)) 989 990 /** 991 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true. 992 * The condition is checked under the lock. This is expected to 993 * be called with the lock taken. 994 * @wq_head: the waitqueue to wait on 995 * @condition: a C expression for the event to wait for 996 * @lock: a locked spinlock_t, which will be released before cmd and 997 * schedule() and reacquired afterwards. 998 * @cmd: a command which is invoked outside the critical section before 999 * sleep 1000 * 1001 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 1002 * @condition evaluates to true or a signal is received. The @condition is 1003 * checked each time the waitqueue @wq_head is woken up. 1004 * 1005 * wake_up() has to be called after changing any variable that could 1006 * change the result of the wait condition. 1007 * 1008 * This is supposed to be called while holding the lock. The lock is 1009 * dropped before invoking the cmd and going to sleep and is reacquired 1010 * afterwards. 1011 * 1012 * The macro will return -ERESTARTSYS if it was interrupted by a signal 1013 * and 0 if @condition evaluated to true. 1014 */ 1015 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd) \ 1016 ({ \ 1017 int __ret = 0; \ 1018 if (!(condition)) \ 1019 __ret = __wait_event_interruptible_lock_irq(wq_head, \ 1020 condition, lock, cmd); \ 1021 __ret; \ 1022 }) 1023 1024 /** 1025 * wait_event_interruptible_lock_irq - sleep until a condition gets true. 1026 * The condition is checked under the lock. This is expected 1027 * to be called with the lock taken. 1028 * @wq_head: the waitqueue to wait on 1029 * @condition: a C expression for the event to wait for 1030 * @lock: a locked spinlock_t, which will be released before schedule() 1031 * and reacquired afterwards. 1032 * 1033 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 1034 * @condition evaluates to true or signal is received. The @condition is 1035 * checked each time the waitqueue @wq_head is woken up. 1036 * 1037 * wake_up() has to be called after changing any variable that could 1038 * change the result of the wait condition. 1039 * 1040 * This is supposed to be called while holding the lock. The lock is 1041 * dropped before going to sleep and is reacquired afterwards. 1042 * 1043 * The macro will return -ERESTARTSYS if it was interrupted by a signal 1044 * and 0 if @condition evaluated to true. 1045 */ 1046 #define wait_event_interruptible_lock_irq(wq_head, condition, lock) \ 1047 ({ \ 1048 int __ret = 0; \ 1049 if (!(condition)) \ 1050 __ret = __wait_event_interruptible_lock_irq(wq_head, \ 1051 condition, lock,); \ 1052 __ret; \ 1053 }) 1054 1055 #define __wait_event_interruptible_lock_irq_timeout(wq_head, condition, \ 1056 lock, timeout) \ 1057 ___wait_event(wq_head, ___wait_cond_timeout(condition), \ 1058 TASK_INTERRUPTIBLE, 0, timeout, \ 1059 spin_unlock_irq(&lock); \ 1060 __ret = schedule_timeout(__ret); \ 1061 spin_lock_irq(&lock)); 1062 1063 /** 1064 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets 1065 * true or a timeout elapses. The condition is checked under 1066 * the lock. This is expected to be called with the lock taken. 1067 * @wq_head: the waitqueue to wait on 1068 * @condition: a C expression for the event to wait for 1069 * @lock: a locked spinlock_t, which will be released before schedule() 1070 * and reacquired afterwards. 1071 * @timeout: timeout, in jiffies 1072 * 1073 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 1074 * @condition evaluates to true or signal is received. The @condition is 1075 * checked each time the waitqueue @wq_head is woken up. 1076 * 1077 * wake_up() has to be called after changing any variable that could 1078 * change the result of the wait condition. 1079 * 1080 * This is supposed to be called while holding the lock. The lock is 1081 * dropped before going to sleep and is reacquired afterwards. 1082 * 1083 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it 1084 * was interrupted by a signal, and the remaining jiffies otherwise 1085 * if the condition evaluated to true before the timeout elapsed. 1086 */ 1087 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock, \ 1088 timeout) \ 1089 ({ \ 1090 long __ret = timeout; \ 1091 if (!___wait_cond_timeout(condition)) \ 1092 __ret = __wait_event_interruptible_lock_irq_timeout( \ 1093 wq_head, condition, lock, timeout); \ 1094 __ret; \ 1095 }) 1096 1097 /* 1098 * Waitqueues which are removed from the waitqueue_head at wakeup time 1099 */ 1100 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); 1101 void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); 1102 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); 1103 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); 1104 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout); 1105 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); 1106 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); 1107 1108 #define DEFINE_WAIT_FUNC(name, function) \ 1109 struct wait_queue_entry name = { \ 1110 .private = current, \ 1111 .func = function, \ 1112 .entry = LIST_HEAD_INIT((name).entry), \ 1113 } 1114 1115 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function) 1116 1117 #define init_wait(wait) \ 1118 do { \ 1119 (wait)->private = current; \ 1120 (wait)->func = autoremove_wake_function; \ 1121 INIT_LIST_HEAD(&(wait)->entry); \ 1122 (wait)->flags = 0; \ 1123 } while (0) 1124 1125 #endif /* _LINUX_WAIT_H */ 1126