1 #ifndef _LINUX_WAIT_H 2 #define _LINUX_WAIT_H 3 /* 4 * Linux wait queue related types and methods 5 */ 6 #include <linux/list.h> 7 #include <linux/stddef.h> 8 #include <linux/spinlock.h> 9 #include <asm/current.h> 10 #include <uapi/linux/wait.h> 11 12 typedef struct __wait_queue wait_queue_t; 13 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key); 14 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key); 15 16 /* __wait_queue::flags */ 17 #define WQ_FLAG_EXCLUSIVE 0x01 18 #define WQ_FLAG_WOKEN 0x02 19 20 struct __wait_queue { 21 unsigned int flags; 22 void *private; 23 wait_queue_func_t func; 24 struct list_head task_list; 25 }; 26 27 struct wait_bit_key { 28 void *flags; 29 int bit_nr; 30 #define WAIT_ATOMIC_T_BIT_NR -1 31 unsigned long timeout; 32 }; 33 34 struct wait_bit_queue { 35 struct wait_bit_key key; 36 wait_queue_t wait; 37 }; 38 39 struct __wait_queue_head { 40 spinlock_t lock; 41 struct list_head task_list; 42 }; 43 typedef struct __wait_queue_head wait_queue_head_t; 44 45 struct task_struct; 46 47 /* 48 * Macros for declaration and initialisaton of the datatypes 49 */ 50 51 #define __WAITQUEUE_INITIALIZER(name, tsk) { \ 52 .private = tsk, \ 53 .func = default_wake_function, \ 54 .task_list = { NULL, NULL } } 55 56 #define DECLARE_WAITQUEUE(name, tsk) \ 57 wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk) 58 59 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ 60 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ 61 .task_list = { &(name).task_list, &(name).task_list } } 62 63 #define DECLARE_WAIT_QUEUE_HEAD(name) \ 64 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name) 65 66 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \ 67 { .flags = word, .bit_nr = bit, } 68 69 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \ 70 { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, } 71 72 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *); 73 74 #define init_waitqueue_head(q) \ 75 do { \ 76 static struct lock_class_key __key; \ 77 \ 78 __init_waitqueue_head((q), #q, &__key); \ 79 } while (0) 80 81 #ifdef CONFIG_LOCKDEP 82 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \ 83 ({ init_waitqueue_head(&name); name; }) 84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \ 85 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) 86 #else 87 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) 88 #endif 89 90 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) 91 { 92 q->flags = 0; 93 q->private = p; 94 q->func = default_wake_function; 95 } 96 97 static inline void 98 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func) 99 { 100 q->flags = 0; 101 q->private = NULL; 102 q->func = func; 103 } 104 105 /** 106 * waitqueue_active -- locklessly test for waiters on the queue 107 * @q: the waitqueue to test for waiters 108 * 109 * returns true if the wait list is not empty 110 * 111 * NOTE: this function is lockless and requires care, incorrect usage _will_ 112 * lead to sporadic and non-obvious failure. 113 * 114 * Use either while holding wait_queue_head_t::lock or when used for wakeups 115 * with an extra smp_mb() like: 116 * 117 * CPU0 - waker CPU1 - waiter 118 * 119 * for (;;) { 120 * @cond = true; prepare_to_wait(&wq, &wait, state); 121 * smp_mb(); // smp_mb() from set_current_state() 122 * if (waitqueue_active(wq)) if (@cond) 123 * wake_up(wq); break; 124 * schedule(); 125 * } 126 * finish_wait(&wq, &wait); 127 * 128 * Because without the explicit smp_mb() it's possible for the 129 * waitqueue_active() load to get hoisted over the @cond store such that we'll 130 * observe an empty wait list while the waiter might not observe @cond. 131 * 132 * Also note that this 'optimization' trades a spin_lock() for an smp_mb(), 133 * which (when the lock is uncontended) are of roughly equal cost. 134 */ 135 static inline int waitqueue_active(wait_queue_head_t *q) 136 { 137 return !list_empty(&q->task_list); 138 } 139 140 /** 141 * wq_has_sleeper - check if there are any waiting processes 142 * @wq: wait queue head 143 * 144 * Returns true if wq has waiting processes 145 * 146 * Please refer to the comment for waitqueue_active. 147 */ 148 static inline bool wq_has_sleeper(wait_queue_head_t *wq) 149 { 150 /* 151 * We need to be sure we are in sync with the 152 * add_wait_queue modifications to the wait queue. 153 * 154 * This memory barrier should be paired with one on the 155 * waiting side. 156 */ 157 smp_mb(); 158 return waitqueue_active(wq); 159 } 160 161 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait); 162 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait); 163 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait); 164 165 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new) 166 { 167 list_add(&new->task_list, &head->task_list); 168 } 169 170 /* 171 * Used for wake-one threads: 172 */ 173 static inline void 174 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait) 175 { 176 wait->flags |= WQ_FLAG_EXCLUSIVE; 177 __add_wait_queue(q, wait); 178 } 179 180 static inline void __add_wait_queue_tail(wait_queue_head_t *head, 181 wait_queue_t *new) 182 { 183 list_add_tail(&new->task_list, &head->task_list); 184 } 185 186 static inline void 187 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait) 188 { 189 wait->flags |= WQ_FLAG_EXCLUSIVE; 190 __add_wait_queue_tail(q, wait); 191 } 192 193 static inline void 194 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old) 195 { 196 list_del(&old->task_list); 197 } 198 199 typedef int wait_bit_action_f(struct wait_bit_key *, int mode); 200 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key); 201 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key); 202 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key); 203 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr); 204 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr); 205 void __wake_up_bit(wait_queue_head_t *, void *, int); 206 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); 207 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); 208 void wake_up_bit(void *, int); 209 void wake_up_atomic_t(atomic_t *); 210 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned); 211 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long); 212 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned); 213 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned); 214 wait_queue_head_t *bit_waitqueue(void *, int); 215 216 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) 217 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) 218 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) 219 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1) 220 #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0) 221 222 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) 223 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL) 224 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL) 225 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1) 226 227 /* 228 * Wakeup macros to be used to report events to the targets. 229 */ 230 #define wake_up_poll(x, m) \ 231 __wake_up(x, TASK_NORMAL, 1, (void *) (m)) 232 #define wake_up_locked_poll(x, m) \ 233 __wake_up_locked_key((x), TASK_NORMAL, (void *) (m)) 234 #define wake_up_interruptible_poll(x, m) \ 235 __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m)) 236 #define wake_up_interruptible_sync_poll(x, m) \ 237 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m)) 238 239 #define ___wait_cond_timeout(condition) \ 240 ({ \ 241 bool __cond = (condition); \ 242 if (__cond && !__ret) \ 243 __ret = 1; \ 244 __cond || !__ret; \ 245 }) 246 247 #define ___wait_is_interruptible(state) \ 248 (!__builtin_constant_p(state) || \ 249 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \ 250 251 /* 252 * The below macro ___wait_event() has an explicit shadow of the __ret 253 * variable when used from the wait_event_*() macros. 254 * 255 * This is so that both can use the ___wait_cond_timeout() construct 256 * to wrap the condition. 257 * 258 * The type inconsistency of the wait_event_*() __ret variable is also 259 * on purpose; we use long where we can return timeout values and int 260 * otherwise. 261 */ 262 263 #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \ 264 ({ \ 265 __label__ __out; \ 266 wait_queue_t __wait; \ 267 long __ret = ret; /* explicit shadow */ \ 268 \ 269 INIT_LIST_HEAD(&__wait.task_list); \ 270 if (exclusive) \ 271 __wait.flags = WQ_FLAG_EXCLUSIVE; \ 272 else \ 273 __wait.flags = 0; \ 274 \ 275 for (;;) { \ 276 long __int = prepare_to_wait_event(&wq, &__wait, state);\ 277 \ 278 if (condition) \ 279 break; \ 280 \ 281 if (___wait_is_interruptible(state) && __int) { \ 282 __ret = __int; \ 283 if (exclusive) { \ 284 abort_exclusive_wait(&wq, &__wait, \ 285 state, NULL); \ 286 goto __out; \ 287 } \ 288 break; \ 289 } \ 290 \ 291 cmd; \ 292 } \ 293 finish_wait(&wq, &__wait); \ 294 __out: __ret; \ 295 }) 296 297 #define __wait_event(wq, condition) \ 298 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 299 schedule()) 300 301 /** 302 * wait_event - sleep until a condition gets true 303 * @wq: the waitqueue to wait on 304 * @condition: a C expression for the event to wait for 305 * 306 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 307 * @condition evaluates to true. The @condition is checked each time 308 * the waitqueue @wq is woken up. 309 * 310 * wake_up() has to be called after changing any variable that could 311 * change the result of the wait condition. 312 */ 313 #define wait_event(wq, condition) \ 314 do { \ 315 might_sleep(); \ 316 if (condition) \ 317 break; \ 318 __wait_event(wq, condition); \ 319 } while (0) 320 321 #define __io_wait_event(wq, condition) \ 322 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 323 io_schedule()) 324 325 /* 326 * io_wait_event() -- like wait_event() but with io_schedule() 327 */ 328 #define io_wait_event(wq, condition) \ 329 do { \ 330 might_sleep(); \ 331 if (condition) \ 332 break; \ 333 __io_wait_event(wq, condition); \ 334 } while (0) 335 336 #define __wait_event_freezable(wq, condition) \ 337 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \ 338 schedule(); try_to_freeze()) 339 340 /** 341 * wait_event_freezable - sleep (or freeze) until a condition gets true 342 * @wq: the waitqueue to wait on 343 * @condition: a C expression for the event to wait for 344 * 345 * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute 346 * to system load) until the @condition evaluates to true. The 347 * @condition is checked each time the waitqueue @wq 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 #define wait_event_freezable(wq, condition) \ 353 ({ \ 354 int __ret = 0; \ 355 might_sleep(); \ 356 if (!(condition)) \ 357 __ret = __wait_event_freezable(wq, condition); \ 358 __ret; \ 359 }) 360 361 #define __wait_event_timeout(wq, condition, timeout) \ 362 ___wait_event(wq, ___wait_cond_timeout(condition), \ 363 TASK_UNINTERRUPTIBLE, 0, timeout, \ 364 __ret = schedule_timeout(__ret)) 365 366 /** 367 * wait_event_timeout - sleep until a condition gets true or a timeout elapses 368 * @wq: the waitqueue to wait on 369 * @condition: a C expression for the event to wait for 370 * @timeout: timeout, in jiffies 371 * 372 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 373 * @condition evaluates to true. The @condition is checked each time 374 * the waitqueue @wq is woken up. 375 * 376 * wake_up() has to be called after changing any variable that could 377 * change the result of the wait condition. 378 * 379 * Returns: 380 * 0 if the @condition evaluated to %false after the @timeout elapsed, 381 * 1 if the @condition evaluated to %true after the @timeout elapsed, 382 * or the remaining jiffies (at least 1) if the @condition evaluated 383 * to %true before the @timeout elapsed. 384 */ 385 #define wait_event_timeout(wq, condition, timeout) \ 386 ({ \ 387 long __ret = timeout; \ 388 might_sleep(); \ 389 if (!___wait_cond_timeout(condition)) \ 390 __ret = __wait_event_timeout(wq, condition, timeout); \ 391 __ret; \ 392 }) 393 394 #define __wait_event_freezable_timeout(wq, condition, timeout) \ 395 ___wait_event(wq, ___wait_cond_timeout(condition), \ 396 TASK_INTERRUPTIBLE, 0, timeout, \ 397 __ret = schedule_timeout(__ret); try_to_freeze()) 398 399 /* 400 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid 401 * increasing load and is freezable. 402 */ 403 #define wait_event_freezable_timeout(wq, condition, timeout) \ 404 ({ \ 405 long __ret = timeout; \ 406 might_sleep(); \ 407 if (!___wait_cond_timeout(condition)) \ 408 __ret = __wait_event_freezable_timeout(wq, condition, timeout); \ 409 __ret; \ 410 }) 411 412 #define __wait_event_exclusive_cmd(wq, condition, cmd1, cmd2) \ 413 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 1, 0, \ 414 cmd1; schedule(); cmd2) 415 /* 416 * Just like wait_event_cmd(), except it sets exclusive flag 417 */ 418 #define wait_event_exclusive_cmd(wq, condition, cmd1, cmd2) \ 419 do { \ 420 if (condition) \ 421 break; \ 422 __wait_event_exclusive_cmd(wq, condition, cmd1, cmd2); \ 423 } while (0) 424 425 #define __wait_event_cmd(wq, condition, cmd1, cmd2) \ 426 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 427 cmd1; schedule(); cmd2) 428 429 /** 430 * wait_event_cmd - sleep until a condition gets true 431 * @wq: the waitqueue to wait on 432 * @condition: a C expression for the event to wait for 433 * @cmd1: the command will be executed before sleep 434 * @cmd2: the command will be executed after sleep 435 * 436 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 437 * @condition evaluates to true. The @condition is checked each time 438 * the waitqueue @wq is woken up. 439 * 440 * wake_up() has to be called after changing any variable that could 441 * change the result of the wait condition. 442 */ 443 #define wait_event_cmd(wq, condition, cmd1, cmd2) \ 444 do { \ 445 if (condition) \ 446 break; \ 447 __wait_event_cmd(wq, condition, cmd1, cmd2); \ 448 } while (0) 449 450 #define __wait_event_interruptible(wq, condition) \ 451 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \ 452 schedule()) 453 454 /** 455 * wait_event_interruptible - sleep until a condition gets true 456 * @wq: the waitqueue to wait on 457 * @condition: a C expression for the event to wait for 458 * 459 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 460 * @condition evaluates to true or a signal is received. 461 * The @condition is checked each time the waitqueue @wq is woken up. 462 * 463 * wake_up() has to be called after changing any variable that could 464 * change the result of the wait condition. 465 * 466 * The function will return -ERESTARTSYS if it was interrupted by a 467 * signal and 0 if @condition evaluated to true. 468 */ 469 #define wait_event_interruptible(wq, condition) \ 470 ({ \ 471 int __ret = 0; \ 472 might_sleep(); \ 473 if (!(condition)) \ 474 __ret = __wait_event_interruptible(wq, condition); \ 475 __ret; \ 476 }) 477 478 #define __wait_event_interruptible_timeout(wq, condition, timeout) \ 479 ___wait_event(wq, ___wait_cond_timeout(condition), \ 480 TASK_INTERRUPTIBLE, 0, timeout, \ 481 __ret = schedule_timeout(__ret)) 482 483 /** 484 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses 485 * @wq: the waitqueue to wait on 486 * @condition: a C expression for the event to wait for 487 * @timeout: timeout, in jiffies 488 * 489 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 490 * @condition evaluates to true or a signal is received. 491 * The @condition is checked each time the waitqueue @wq is woken up. 492 * 493 * wake_up() has to be called after changing any variable that could 494 * change the result of the wait condition. 495 * 496 * Returns: 497 * 0 if the @condition evaluated to %false after the @timeout elapsed, 498 * 1 if the @condition evaluated to %true after the @timeout elapsed, 499 * the remaining jiffies (at least 1) if the @condition evaluated 500 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was 501 * interrupted by a signal. 502 */ 503 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 504 ({ \ 505 long __ret = timeout; \ 506 might_sleep(); \ 507 if (!___wait_cond_timeout(condition)) \ 508 __ret = __wait_event_interruptible_timeout(wq, \ 509 condition, timeout); \ 510 __ret; \ 511 }) 512 513 #define __wait_event_hrtimeout(wq, condition, timeout, state) \ 514 ({ \ 515 int __ret = 0; \ 516 struct hrtimer_sleeper __t; \ 517 \ 518 hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, \ 519 HRTIMER_MODE_REL); \ 520 hrtimer_init_sleeper(&__t, current); \ 521 if ((timeout).tv64 != KTIME_MAX) \ 522 hrtimer_start_range_ns(&__t.timer, timeout, \ 523 current->timer_slack_ns, \ 524 HRTIMER_MODE_REL); \ 525 \ 526 __ret = ___wait_event(wq, condition, state, 0, 0, \ 527 if (!__t.task) { \ 528 __ret = -ETIME; \ 529 break; \ 530 } \ 531 schedule()); \ 532 \ 533 hrtimer_cancel(&__t.timer); \ 534 destroy_hrtimer_on_stack(&__t.timer); \ 535 __ret; \ 536 }) 537 538 /** 539 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses 540 * @wq: the waitqueue to wait on 541 * @condition: a C expression for the event to wait for 542 * @timeout: timeout, as a ktime_t 543 * 544 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 545 * @condition evaluates to true or a signal is received. 546 * The @condition is checked each time the waitqueue @wq is woken up. 547 * 548 * wake_up() has to be called after changing any variable that could 549 * change the result of the wait condition. 550 * 551 * The function returns 0 if @condition became true, or -ETIME if the timeout 552 * elapsed. 553 */ 554 #define wait_event_hrtimeout(wq, condition, timeout) \ 555 ({ \ 556 int __ret = 0; \ 557 might_sleep(); \ 558 if (!(condition)) \ 559 __ret = __wait_event_hrtimeout(wq, condition, timeout, \ 560 TASK_UNINTERRUPTIBLE); \ 561 __ret; \ 562 }) 563 564 /** 565 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses 566 * @wq: the waitqueue to wait on 567 * @condition: a C expression for the event to wait for 568 * @timeout: timeout, as a ktime_t 569 * 570 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 571 * @condition evaluates to true or a signal is received. 572 * The @condition is checked each time the waitqueue @wq is woken up. 573 * 574 * wake_up() has to be called after changing any variable that could 575 * change the result of the wait condition. 576 * 577 * The function returns 0 if @condition became true, -ERESTARTSYS if it was 578 * interrupted by a signal, or -ETIME if the timeout elapsed. 579 */ 580 #define wait_event_interruptible_hrtimeout(wq, condition, timeout) \ 581 ({ \ 582 long __ret = 0; \ 583 might_sleep(); \ 584 if (!(condition)) \ 585 __ret = __wait_event_hrtimeout(wq, condition, timeout, \ 586 TASK_INTERRUPTIBLE); \ 587 __ret; \ 588 }) 589 590 #define __wait_event_interruptible_exclusive(wq, condition) \ 591 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \ 592 schedule()) 593 594 #define wait_event_interruptible_exclusive(wq, condition) \ 595 ({ \ 596 int __ret = 0; \ 597 might_sleep(); \ 598 if (!(condition)) \ 599 __ret = __wait_event_interruptible_exclusive(wq, condition);\ 600 __ret; \ 601 }) 602 603 604 #define __wait_event_freezable_exclusive(wq, condition) \ 605 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \ 606 schedule(); try_to_freeze()) 607 608 #define wait_event_freezable_exclusive(wq, condition) \ 609 ({ \ 610 int __ret = 0; \ 611 might_sleep(); \ 612 if (!(condition)) \ 613 __ret = __wait_event_freezable_exclusive(wq, condition);\ 614 __ret; \ 615 }) 616 617 618 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \ 619 ({ \ 620 int __ret = 0; \ 621 DEFINE_WAIT(__wait); \ 622 if (exclusive) \ 623 __wait.flags |= WQ_FLAG_EXCLUSIVE; \ 624 do { \ 625 if (likely(list_empty(&__wait.task_list))) \ 626 __add_wait_queue_tail(&(wq), &__wait); \ 627 set_current_state(TASK_INTERRUPTIBLE); \ 628 if (signal_pending(current)) { \ 629 __ret = -ERESTARTSYS; \ 630 break; \ 631 } \ 632 if (irq) \ 633 spin_unlock_irq(&(wq).lock); \ 634 else \ 635 spin_unlock(&(wq).lock); \ 636 schedule(); \ 637 if (irq) \ 638 spin_lock_irq(&(wq).lock); \ 639 else \ 640 spin_lock(&(wq).lock); \ 641 } while (!(condition)); \ 642 __remove_wait_queue(&(wq), &__wait); \ 643 __set_current_state(TASK_RUNNING); \ 644 __ret; \ 645 }) 646 647 648 /** 649 * wait_event_interruptible_locked - sleep until a condition gets true 650 * @wq: the waitqueue to wait on 651 * @condition: a C expression for the event to wait for 652 * 653 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 654 * @condition evaluates to true or a signal is received. 655 * The @condition is checked each time the waitqueue @wq is woken up. 656 * 657 * It must be called with wq.lock being held. This spinlock is 658 * unlocked while sleeping but @condition testing is done while lock 659 * is held and when this macro exits the lock is held. 660 * 661 * The lock is locked/unlocked using spin_lock()/spin_unlock() 662 * functions which must match the way they are locked/unlocked outside 663 * of this macro. 664 * 665 * wake_up_locked() has to be called after changing any variable that could 666 * change the result of the wait condition. 667 * 668 * The function will return -ERESTARTSYS if it was interrupted by a 669 * signal and 0 if @condition evaluated to true. 670 */ 671 #define wait_event_interruptible_locked(wq, condition) \ 672 ((condition) \ 673 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0)) 674 675 /** 676 * wait_event_interruptible_locked_irq - sleep until a condition gets true 677 * @wq: the waitqueue to wait on 678 * @condition: a C expression for the event to wait for 679 * 680 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 681 * @condition evaluates to true or a signal is received. 682 * The @condition is checked each time the waitqueue @wq is woken up. 683 * 684 * It must be called with wq.lock being held. This spinlock is 685 * unlocked while sleeping but @condition testing is done while lock 686 * is held and when this macro exits the lock is held. 687 * 688 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq() 689 * functions which must match the way they are locked/unlocked outside 690 * of this macro. 691 * 692 * wake_up_locked() has to be called after changing any variable that could 693 * change the result of the wait condition. 694 * 695 * The function will return -ERESTARTSYS if it was interrupted by a 696 * signal and 0 if @condition evaluated to true. 697 */ 698 #define wait_event_interruptible_locked_irq(wq, condition) \ 699 ((condition) \ 700 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1)) 701 702 /** 703 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true 704 * @wq: the waitqueue to wait on 705 * @condition: a C expression for the event to wait for 706 * 707 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 708 * @condition evaluates to true or a signal is received. 709 * The @condition is checked each time the waitqueue @wq is woken up. 710 * 711 * It must be called with wq.lock being held. This spinlock is 712 * unlocked while sleeping but @condition testing is done while lock 713 * is held and when this macro exits the lock is held. 714 * 715 * The lock is locked/unlocked using spin_lock()/spin_unlock() 716 * functions which must match the way they are locked/unlocked outside 717 * of this macro. 718 * 719 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag 720 * set thus when other process waits process on the list if this 721 * process is awaken further processes are not considered. 722 * 723 * wake_up_locked() has to be called after changing any variable that could 724 * change the result of the wait condition. 725 * 726 * The function will return -ERESTARTSYS if it was interrupted by a 727 * signal and 0 if @condition evaluated to true. 728 */ 729 #define wait_event_interruptible_exclusive_locked(wq, condition) \ 730 ((condition) \ 731 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0)) 732 733 /** 734 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true 735 * @wq: the waitqueue to wait on 736 * @condition: a C expression for the event to wait for 737 * 738 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 739 * @condition evaluates to true or a signal is received. 740 * The @condition is checked each time the waitqueue @wq is woken up. 741 * 742 * It must be called with wq.lock being held. This spinlock is 743 * unlocked while sleeping but @condition testing is done while lock 744 * is held and when this macro exits the lock is held. 745 * 746 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq() 747 * functions which must match the way they are locked/unlocked outside 748 * of this macro. 749 * 750 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag 751 * set thus when other process waits process on the list if this 752 * process is awaken further processes are not considered. 753 * 754 * wake_up_locked() has to be called after changing any variable that could 755 * change the result of the wait condition. 756 * 757 * The function will return -ERESTARTSYS if it was interrupted by a 758 * signal and 0 if @condition evaluated to true. 759 */ 760 #define wait_event_interruptible_exclusive_locked_irq(wq, condition) \ 761 ((condition) \ 762 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1)) 763 764 765 #define __wait_event_killable(wq, condition) \ 766 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule()) 767 768 /** 769 * wait_event_killable - sleep until a condition gets true 770 * @wq: the waitqueue to wait on 771 * @condition: a C expression for the event to wait for 772 * 773 * The process is put to sleep (TASK_KILLABLE) until the 774 * @condition evaluates to true or a signal is received. 775 * The @condition is checked each time the waitqueue @wq is woken up. 776 * 777 * wake_up() has to be called after changing any variable that could 778 * change the result of the wait condition. 779 * 780 * The function will return -ERESTARTSYS if it was interrupted by a 781 * signal and 0 if @condition evaluated to true. 782 */ 783 #define wait_event_killable(wq, condition) \ 784 ({ \ 785 int __ret = 0; \ 786 might_sleep(); \ 787 if (!(condition)) \ 788 __ret = __wait_event_killable(wq, condition); \ 789 __ret; \ 790 }) 791 792 793 #define __wait_event_lock_irq(wq, condition, lock, cmd) \ 794 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ 795 spin_unlock_irq(&lock); \ 796 cmd; \ 797 schedule(); \ 798 spin_lock_irq(&lock)) 799 800 /** 801 * wait_event_lock_irq_cmd - sleep until a condition gets true. The 802 * condition is checked under the lock. This 803 * is expected to be called with the lock 804 * taken. 805 * @wq: the waitqueue to wait on 806 * @condition: a C expression for the event to wait for 807 * @lock: a locked spinlock_t, which will be released before cmd 808 * and schedule() and reacquired afterwards. 809 * @cmd: a command which is invoked outside the critical section before 810 * sleep 811 * 812 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 813 * @condition evaluates to true. The @condition is checked each time 814 * the waitqueue @wq is woken up. 815 * 816 * wake_up() has to be called after changing any variable that could 817 * change the result of the wait condition. 818 * 819 * This is supposed to be called while holding the lock. The lock is 820 * dropped before invoking the cmd and going to sleep and is reacquired 821 * afterwards. 822 */ 823 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd) \ 824 do { \ 825 if (condition) \ 826 break; \ 827 __wait_event_lock_irq(wq, condition, lock, cmd); \ 828 } while (0) 829 830 /** 831 * wait_event_lock_irq - sleep until a condition gets true. The 832 * condition is checked under the lock. This 833 * is expected to be called with the lock 834 * taken. 835 * @wq: the waitqueue to wait on 836 * @condition: a C expression for the event to wait for 837 * @lock: a locked spinlock_t, which will be released before schedule() 838 * and reacquired afterwards. 839 * 840 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the 841 * @condition evaluates to true. The @condition is checked each time 842 * the waitqueue @wq is woken up. 843 * 844 * wake_up() has to be called after changing any variable that could 845 * change the result of the wait condition. 846 * 847 * This is supposed to be called while holding the lock. The lock is 848 * dropped before going to sleep and is reacquired afterwards. 849 */ 850 #define wait_event_lock_irq(wq, condition, lock) \ 851 do { \ 852 if (condition) \ 853 break; \ 854 __wait_event_lock_irq(wq, condition, lock, ); \ 855 } while (0) 856 857 858 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd) \ 859 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \ 860 spin_unlock_irq(&lock); \ 861 cmd; \ 862 schedule(); \ 863 spin_lock_irq(&lock)) 864 865 /** 866 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true. 867 * The condition is checked under the lock. This is expected to 868 * be called with the lock taken. 869 * @wq: the waitqueue to wait on 870 * @condition: a C expression for the event to wait for 871 * @lock: a locked spinlock_t, which will be released before cmd and 872 * schedule() and reacquired afterwards. 873 * @cmd: a command which is invoked outside the critical section before 874 * sleep 875 * 876 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 877 * @condition evaluates to true or a signal is received. The @condition is 878 * checked each time the waitqueue @wq is woken up. 879 * 880 * wake_up() has to be called after changing any variable that could 881 * change the result of the wait condition. 882 * 883 * This is supposed to be called while holding the lock. The lock is 884 * dropped before invoking the cmd and going to sleep and is reacquired 885 * afterwards. 886 * 887 * The macro will return -ERESTARTSYS if it was interrupted by a signal 888 * and 0 if @condition evaluated to true. 889 */ 890 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \ 891 ({ \ 892 int __ret = 0; \ 893 if (!(condition)) \ 894 __ret = __wait_event_interruptible_lock_irq(wq, \ 895 condition, lock, cmd); \ 896 __ret; \ 897 }) 898 899 /** 900 * wait_event_interruptible_lock_irq - sleep until a condition gets true. 901 * The condition is checked under the lock. This is expected 902 * to be called with the lock taken. 903 * @wq: the waitqueue to wait on 904 * @condition: a C expression for the event to wait for 905 * @lock: a locked spinlock_t, which will be released before schedule() 906 * and reacquired afterwards. 907 * 908 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 909 * @condition evaluates to true or signal is received. The @condition is 910 * checked each time the waitqueue @wq is woken up. 911 * 912 * wake_up() has to be called after changing any variable that could 913 * change the result of the wait condition. 914 * 915 * This is supposed to be called while holding the lock. The lock is 916 * dropped before going to sleep and is reacquired afterwards. 917 * 918 * The macro will return -ERESTARTSYS if it was interrupted by a signal 919 * and 0 if @condition evaluated to true. 920 */ 921 #define wait_event_interruptible_lock_irq(wq, condition, lock) \ 922 ({ \ 923 int __ret = 0; \ 924 if (!(condition)) \ 925 __ret = __wait_event_interruptible_lock_irq(wq, \ 926 condition, lock,); \ 927 __ret; \ 928 }) 929 930 #define __wait_event_interruptible_lock_irq_timeout(wq, condition, \ 931 lock, timeout) \ 932 ___wait_event(wq, ___wait_cond_timeout(condition), \ 933 TASK_INTERRUPTIBLE, 0, timeout, \ 934 spin_unlock_irq(&lock); \ 935 __ret = schedule_timeout(__ret); \ 936 spin_lock_irq(&lock)); 937 938 /** 939 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets 940 * true or a timeout elapses. The condition is checked under 941 * the lock. This is expected to be called with the lock taken. 942 * @wq: the waitqueue to wait on 943 * @condition: a C expression for the event to wait for 944 * @lock: a locked spinlock_t, which will be released before schedule() 945 * and reacquired afterwards. 946 * @timeout: timeout, in jiffies 947 * 948 * The process is put to sleep (TASK_INTERRUPTIBLE) until the 949 * @condition evaluates to true or signal is received. The @condition is 950 * checked each time the waitqueue @wq is woken up. 951 * 952 * wake_up() has to be called after changing any variable that could 953 * change the result of the wait condition. 954 * 955 * This is supposed to be called while holding the lock. The lock is 956 * dropped before going to sleep and is reacquired afterwards. 957 * 958 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it 959 * was interrupted by a signal, and the remaining jiffies otherwise 960 * if the condition evaluated to true before the timeout elapsed. 961 */ 962 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \ 963 timeout) \ 964 ({ \ 965 long __ret = timeout; \ 966 if (!___wait_cond_timeout(condition)) \ 967 __ret = __wait_event_interruptible_lock_irq_timeout( \ 968 wq, condition, lock, timeout); \ 969 __ret; \ 970 }) 971 972 /* 973 * Waitqueues which are removed from the waitqueue_head at wakeup time 974 */ 975 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state); 976 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state); 977 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state); 978 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait); 979 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key); 980 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout); 981 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); 982 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); 983 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); 984 985 #define DEFINE_WAIT_FUNC(name, function) \ 986 wait_queue_t name = { \ 987 .private = current, \ 988 .func = function, \ 989 .task_list = LIST_HEAD_INIT((name).task_list), \ 990 } 991 992 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function) 993 994 #define DEFINE_WAIT_BIT(name, word, bit) \ 995 struct wait_bit_queue name = { \ 996 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \ 997 .wait = { \ 998 .private = current, \ 999 .func = wake_bit_function, \ 1000 .task_list = \ 1001 LIST_HEAD_INIT((name).wait.task_list), \ 1002 }, \ 1003 } 1004 1005 #define init_wait(wait) \ 1006 do { \ 1007 (wait)->private = current; \ 1008 (wait)->func = autoremove_wake_function; \ 1009 INIT_LIST_HEAD(&(wait)->task_list); \ 1010 (wait)->flags = 0; \ 1011 } while (0) 1012 1013 1014 extern int bit_wait(struct wait_bit_key *, int); 1015 extern int bit_wait_io(struct wait_bit_key *, int); 1016 extern int bit_wait_timeout(struct wait_bit_key *, int); 1017 extern int bit_wait_io_timeout(struct wait_bit_key *, int); 1018 1019 /** 1020 * wait_on_bit - wait for a bit to be cleared 1021 * @word: the word being waited on, a kernel virtual address 1022 * @bit: the bit of the word being waited on 1023 * @mode: the task state to sleep in 1024 * 1025 * There is a standard hashed waitqueue table for generic use. This 1026 * is the part of the hashtable's accessor API that waits on a bit. 1027 * For instance, if one were to have waiters on a bitflag, one would 1028 * call wait_on_bit() in threads waiting for the bit to clear. 1029 * One uses wait_on_bit() where one is waiting for the bit to clear, 1030 * but has no intention of setting it. 1031 * Returned value will be zero if the bit was cleared, or non-zero 1032 * if the process received a signal and the mode permitted wakeup 1033 * on that signal. 1034 */ 1035 static inline int 1036 wait_on_bit(unsigned long *word, int bit, unsigned mode) 1037 { 1038 might_sleep(); 1039 if (!test_bit(bit, word)) 1040 return 0; 1041 return out_of_line_wait_on_bit(word, bit, 1042 bit_wait, 1043 mode); 1044 } 1045 1046 /** 1047 * wait_on_bit_io - wait for a bit to be cleared 1048 * @word: the word being waited on, a kernel virtual address 1049 * @bit: the bit of the word being waited on 1050 * @mode: the task state to sleep in 1051 * 1052 * Use the standard hashed waitqueue table to wait for a bit 1053 * to be cleared. This is similar to wait_on_bit(), but calls 1054 * io_schedule() instead of schedule() for the actual waiting. 1055 * 1056 * Returned value will be zero if the bit was cleared, or non-zero 1057 * if the process received a signal and the mode permitted wakeup 1058 * on that signal. 1059 */ 1060 static inline int 1061 wait_on_bit_io(unsigned long *word, int bit, unsigned mode) 1062 { 1063 might_sleep(); 1064 if (!test_bit(bit, word)) 1065 return 0; 1066 return out_of_line_wait_on_bit(word, bit, 1067 bit_wait_io, 1068 mode); 1069 } 1070 1071 /** 1072 * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses 1073 * @word: the word being waited on, a kernel virtual address 1074 * @bit: the bit of the word being waited on 1075 * @mode: the task state to sleep in 1076 * @timeout: timeout, in jiffies 1077 * 1078 * Use the standard hashed waitqueue table to wait for a bit 1079 * to be cleared. This is similar to wait_on_bit(), except also takes a 1080 * timeout parameter. 1081 * 1082 * Returned value will be zero if the bit was cleared before the 1083 * @timeout elapsed, or non-zero if the @timeout elapsed or process 1084 * received a signal and the mode permitted wakeup on that signal. 1085 */ 1086 static inline int 1087 wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode, 1088 unsigned long timeout) 1089 { 1090 might_sleep(); 1091 if (!test_bit(bit, word)) 1092 return 0; 1093 return out_of_line_wait_on_bit_timeout(word, bit, 1094 bit_wait_timeout, 1095 mode, timeout); 1096 } 1097 1098 /** 1099 * wait_on_bit_action - wait for a bit to be cleared 1100 * @word: the word being waited on, a kernel virtual address 1101 * @bit: the bit of the word being waited on 1102 * @action: the function used to sleep, which may take special actions 1103 * @mode: the task state to sleep in 1104 * 1105 * Use the standard hashed waitqueue table to wait for a bit 1106 * to be cleared, and allow the waiting action to be specified. 1107 * This is like wait_on_bit() but allows fine control of how the waiting 1108 * is done. 1109 * 1110 * Returned value will be zero if the bit was cleared, or non-zero 1111 * if the process received a signal and the mode permitted wakeup 1112 * on that signal. 1113 */ 1114 static inline int 1115 wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action, 1116 unsigned mode) 1117 { 1118 might_sleep(); 1119 if (!test_bit(bit, word)) 1120 return 0; 1121 return out_of_line_wait_on_bit(word, bit, action, mode); 1122 } 1123 1124 /** 1125 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it 1126 * @word: the word being waited on, a kernel virtual address 1127 * @bit: the bit of the word being waited on 1128 * @mode: the task state to sleep in 1129 * 1130 * There is a standard hashed waitqueue table for generic use. This 1131 * is the part of the hashtable's accessor API that waits on a bit 1132 * when one intends to set it, for instance, trying to lock bitflags. 1133 * For instance, if one were to have waiters trying to set bitflag 1134 * and waiting for it to clear before setting it, one would call 1135 * wait_on_bit() in threads waiting to be able to set the bit. 1136 * One uses wait_on_bit_lock() where one is waiting for the bit to 1137 * clear with the intention of setting it, and when done, clearing it. 1138 * 1139 * Returns zero if the bit was (eventually) found to be clear and was 1140 * set. Returns non-zero if a signal was delivered to the process and 1141 * the @mode allows that signal to wake the process. 1142 */ 1143 static inline int 1144 wait_on_bit_lock(unsigned long *word, int bit, unsigned mode) 1145 { 1146 might_sleep(); 1147 if (!test_and_set_bit(bit, word)) 1148 return 0; 1149 return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode); 1150 } 1151 1152 /** 1153 * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it 1154 * @word: the word being waited on, a kernel virtual address 1155 * @bit: the bit of the word being waited on 1156 * @mode: the task state to sleep in 1157 * 1158 * Use the standard hashed waitqueue table to wait for a bit 1159 * to be cleared and then to atomically set it. This is similar 1160 * to wait_on_bit(), but calls io_schedule() instead of schedule() 1161 * for the actual waiting. 1162 * 1163 * Returns zero if the bit was (eventually) found to be clear and was 1164 * set. Returns non-zero if a signal was delivered to the process and 1165 * the @mode allows that signal to wake the process. 1166 */ 1167 static inline int 1168 wait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode) 1169 { 1170 might_sleep(); 1171 if (!test_and_set_bit(bit, word)) 1172 return 0; 1173 return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode); 1174 } 1175 1176 /** 1177 * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it 1178 * @word: the word being waited on, a kernel virtual address 1179 * @bit: the bit of the word being waited on 1180 * @action: the function used to sleep, which may take special actions 1181 * @mode: the task state to sleep in 1182 * 1183 * Use the standard hashed waitqueue table to wait for a bit 1184 * to be cleared and then to set it, and allow the waiting action 1185 * to be specified. 1186 * This is like wait_on_bit() but allows fine control of how the waiting 1187 * is done. 1188 * 1189 * Returns zero if the bit was (eventually) found to be clear and was 1190 * set. Returns non-zero if a signal was delivered to the process and 1191 * the @mode allows that signal to wake the process. 1192 */ 1193 static inline int 1194 wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action, 1195 unsigned mode) 1196 { 1197 might_sleep(); 1198 if (!test_and_set_bit(bit, word)) 1199 return 0; 1200 return out_of_line_wait_on_bit_lock(word, bit, action, mode); 1201 } 1202 1203 /** 1204 * wait_on_atomic_t - Wait for an atomic_t to become 0 1205 * @val: The atomic value being waited on, a kernel virtual address 1206 * @action: the function used to sleep, which may take special actions 1207 * @mode: the task state to sleep in 1208 * 1209 * Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for 1210 * the purpose of getting a waitqueue, but we set the key to a bit number 1211 * outside of the target 'word'. 1212 */ 1213 static inline 1214 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode) 1215 { 1216 might_sleep(); 1217 if (atomic_read(val) == 0) 1218 return 0; 1219 return out_of_line_wait_on_atomic_t(val, action, mode); 1220 } 1221 1222 #endif /* _LINUX_WAIT_H */ 1223