Whamcloud - gitweb
5a3f548a59f7026a1a1b17851946de075be6f3fd
[fs/lustre-release.git] / libcfs / include / libcfs / linux / linux-wait.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LIBCFS_LINUX_WAIT_BIT_H
3 #define __LIBCFS_LINUX_WAIT_BIT_H
4
5 /* Make sure we can see if we have TASK_NOLOAD */
6 #include <linux/sched.h>
7 /*
8  * Linux wait-bit related types and methods:
9  */
10 #ifdef HAVE_WAIT_BIT_HEADER_H
11 #include <linux/wait_bit.h>
12 #endif
13 #include <linux/wait.h>
14
15 #ifndef HAVE_WAIT_QUEUE_ENTRY
16 #define wait_queue_entry_t wait_queue_t
17 #endif
18
19 #ifndef HAVE_WAIT_BIT_HEADER_H
20 struct wait_bit_queue_entry {
21         struct wait_bit_key     key;
22         wait_queue_entry_t      wq_entry;
23 };
24
25 #define ___wait_is_interruptible(state)                                         \
26         (!__builtin_constant_p(state) ||                                        \
27                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
28
29 #endif /* ! HAVE_WAIT_BIT_HEADER_H */
30
31 #ifndef HAVE_PREPARE_TO_WAIT_EVENT
32 extern long prepare_to_wait_event(wait_queue_head_t *wq_head,
33                                   wait_queue_entry_t *wq_entry, int state);
34 #endif
35
36 /* ___wait_cond_timeout changed number of args in v3.12-rc1-78-g35a2af94c7ce
37  * so let's define our own ___wait_cond_timeout1
38  */
39
40 #define ___wait_cond_timeout1(condition)                                \
41 ({                                                                      \
42         bool __cond = (condition);                                      \
43         if (__cond && !__ret)                                           \
44                 __ret = 1;                                              \
45         __cond || !__ret;                                               \
46 })
47
48 #ifndef HAVE_CLEAR_AND_WAKE_UP_BIT
49 /**
50  * clear_and_wake_up_bit - clear a bit and wake up anyone waiting on that bit
51  *
52  * @bit: the bit of the word being waited on
53  * @word: the word being waited on, a kernel virtual address
54  *
55  * You can use this helper if bitflags are manipulated atomically rather than
56  * non-atomically under a lock.
57  */
58 static inline void clear_and_wake_up_bit(int bit, void *word)
59 {
60         clear_bit_unlock(bit, word);
61         /* See wake_up_bit() for which memory barrier you need to use. */
62         smp_mb__after_atomic();
63         wake_up_bit(word, bit);
64 }
65 #endif /* ! HAVE_CLEAR_AND_WAKE_UP_BIT */
66
67 #ifndef HAVE_WAIT_VAR_EVENT
68 extern void __init wait_bit_init(void);
69 extern void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry,
70                                 void *var, int flags);
71 extern void wake_up_var(void *var);
72 extern wait_queue_head_t *__var_waitqueue(void *p);
73
74 #define ___wait_var_event(var, condition, state, exclusive, ret, cmd)   \
75 ({                                                                      \
76         __label__ __out;                                                \
77         wait_queue_head_t *__wq_head = __var_waitqueue(var);            \
78         struct wait_bit_queue_entry __wbq_entry;                        \
79         long __ret = ret; /* explicit shadow */                         \
80                                                                         \
81         init_wait_var_entry(&__wbq_entry, var,                          \
82                             exclusive ? WQ_FLAG_EXCLUSIVE : 0);         \
83         for (;;) {                                                      \
84                 long __int = prepare_to_wait_event(__wq_head,           \
85                                                    &__wbq_entry.wq_entry, \
86                                                    state);              \
87                 if (condition)                                          \
88                         break;                                          \
89                                                                         \
90                 if (___wait_is_interruptible(state) && __int) {         \
91                         __ret = __int;                                  \
92                         goto __out;                                     \
93                 }                                                       \
94                                                                         \
95                 cmd;                                                    \
96         }                                                               \
97         finish_wait(__wq_head, &__wbq_entry.wq_entry);                  \
98 __out:  __ret;                                                          \
99 })
100
101 #define __wait_var_event(var, condition)                                \
102         ___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0,   \
103                           schedule())
104
105 #define wait_var_event(var, condition)                                  \
106 do {                                                                    \
107         might_sleep();                                                  \
108         if (condition)                                                  \
109                 break;                                                  \
110         __wait_var_event(var, condition);                               \
111 } while (0)
112
113 #define __wait_var_event_killable(var, condition)                       \
114         ___wait_var_event(var, condition, TASK_KILLABLE, 0, 0,          \
115                           schedule())
116
117 #define wait_var_event_killable(var, condition)                         \
118 ({                                                                      \
119         int __ret = 0;                                                  \
120         might_sleep();                                                  \
121         if (!(condition))                                               \
122                 __ret = __wait_var_event_killable(var, condition);      \
123         __ret;                                                          \
124 })
125
126 #define __wait_var_event_timeout(var, condition, timeout)               \
127         ___wait_var_event(var, ___wait_cond_timeout1(condition),        \
128                           TASK_UNINTERRUPTIBLE, 0, timeout,             \
129                           __ret = schedule_timeout(__ret))
130
131 #define wait_var_event_timeout(var, condition, timeout)                 \
132 ({                                                                      \
133         long __ret = timeout;                                           \
134         might_sleep();                                                  \
135         if (!___wait_cond_timeout1(condition))                          \
136                 __ret = __wait_var_event_timeout(var, condition, timeout); \
137         __ret;                                                          \
138 })
139 #endif /* ! HAVE_WAIT_VAR_EVENT */
140
141 /*
142  * prepare_to_wait_event() does not support an exclusive
143  * lifo wait.
144  * However it will not relink the wait_queue_entry if
145  * it is already linked.  So we link to the head of the
146  * queue here, and it will stay there.
147  */
148 static inline void prepare_to_wait_exclusive_head(
149         wait_queue_head_t *waitq, wait_queue_entry_t *link)
150 {
151         unsigned long flags;
152
153         spin_lock_irqsave(&(waitq->lock), flags);
154 #ifdef HAVE_WAIT_QUEUE_ENTRY_LIST
155         if (list_empty(&link->entry))
156 #else
157         if (list_empty(&link->task_list))
158 #endif
159                 __add_wait_queue_exclusive(waitq, link);
160         spin_unlock_irqrestore(&((waitq)->lock), flags);
161 }
162
163 #ifndef ___wait_event
164 /*
165  * The below macro ___wait_event() has an explicit shadow of the __ret
166  * variable when used from the wait_event_*() macros.
167  *
168  * This is so that both can use the ___wait_cond_timeout1() construct
169  * to wrap the condition.
170  *
171  * The type inconsistency of the wait_event_*() __ret variable is also
172  * on purpose; we use long where we can return timeout values and int
173  * otherwise.
174  */
175
176 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)   \
177 ({                                                                      \
178         __label__ __out;                                                \
179         wait_queue_entry_ __wq_entry;                                   \
180         long __ret = ret;       /* explicit shadow */                   \
181                                                                         \
182         init_wait(&__wq_entry);                                         \
183         if (exclusive)                                                  \
184                 __wq_entry.flags = WQ_FLAG_EXCLUSIVE                    \
185         for (;;) {                                                      \
186                 long __int = prepare_to_wait_event(&wq_head,            \
187                                                   &__wq_entry, state);  \
188                                                                         \
189                 if (condition)                                          \
190                         break;                                          \
191                                                                         \
192                 if (___wait_is_interruptible(state) && __int) {         \
193                         __ret = __int;                                  \
194                         goto __out;                                     \
195                 }                                                       \
196                                                                         \
197                 cmd;                                                    \
198         }                                                               \
199         finish_wait(&wq_head, &__wq_entry);                             \
200 __out:  __ret;                                                          \
201 })
202 #endif
203
204 #ifndef TASK_NOLOAD
205
206 #define ___wait_event_idle(wq_head, condition, exclusive, ret, cmd)     \
207 ({                                                                      \
208         wait_queue_entry_t __wq_entry;                                  \
209         unsigned long flags;                                            \
210         long __ret = ret;       /* explicit shadow */                   \
211         sigset_t __old_blocked;                                         \
212                                                                         \
213         cfs_block_sigsinv(0, &__old_blocked);                           \
214         init_wait(&__wq_entry);                                         \
215         if (exclusive)                                                  \
216                 __wq_entry.flags = WQ_FLAG_EXCLUSIVE;                   \
217         for (;;) {                                                      \
218                 prepare_to_wait_event(&wq_head,                         \
219                                    &__wq_entry,                         \
220                                    TASK_INTERRUPTIBLE);                 \
221                                                                         \
222                 if (condition)                                          \
223                         break;                                          \
224                 /* We have to do this here because some signals */      \
225                 /* are not blockable - ie from strace(1).       */      \
226                 /* In these cases we want to schedule_timeout() */      \
227                 /* again, because we don't want that to return  */      \
228                 /* -EINTR when the RPC actually succeeded.      */      \
229                 /* the recalc_sigpending() below will deliver the */    \
230                 /* signal properly.                             */      \
231                 if (signal_pending(current)) {                          \
232                         spin_lock_irqsave(&current->sighand->siglock,   \
233                                           flags);                       \
234                         clear_tsk_thread_flag(current, TIF_SIGPENDING); \
235                         spin_unlock_irqrestore(&current->sighand->siglock,\
236                                                flags);                  \
237                 }                                                       \
238                 cmd;                                                    \
239         }                                                               \
240         finish_wait(&wq_head, &__wq_entry);                             \
241         cfs_restore_sigs(&__old_blocked);                               \
242         __ret;                                                          \
243 })
244
245 #define wait_event_idle(wq_head, condition)                             \
246 do {                                                                    \
247         might_sleep();                                                  \
248         if (!(condition))                                               \
249                 ___wait_event_idle(wq_head, condition, 0, 0, schedule());\
250 } while (0)
251
252 #define wait_event_idle_exclusive(wq_head, condition)                   \
253 do {                                                                    \
254         might_sleep();                                                  \
255         if (!(condition))                                               \
256                 ___wait_event_idle(wq_head, condition, 1, 0, schedule());\
257 } while (0)
258
259 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)\
260         ___wait_event_idle(wq_head, ___wait_cond_timeout1(condition),   \
261                            1, timeout,                                  \
262                            __ret = schedule_timeout(__ret))
263
264 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)  \
265 ({                                                                      \
266         long __ret = timeout;                                           \
267         might_sleep();                                                  \
268         if (!___wait_cond_timeout1(condition))                          \
269                 __ret = __wait_event_idle_exclusive_timeout(            \
270                         wq_head, condition, timeout);                   \
271         __ret;                                                          \
272 })
273
274 #define __wait_event_idle_exclusive_timeout_cmd(wq_head, condition,     \
275                                                 timeout, cmd1, cmd2)    \
276         ___wait_event_idle(wq_head, ___wait_cond_timeout1(condition),   \
277                            1, timeout,                                  \
278                            cmd1; __ret = schedule_timeout(__ret); cmd2)
279
280 #define wait_event_idle_exclusive_timeout_cmd(wq_head, condition, timeout,\
281                                               cmd1, cmd2)               \
282 ({                                                                      \
283         long __ret = timeout;                                           \
284         if (!___wait_cond_timeout1(condition))                          \
285                 __ret = __wait_event_idle_exclusive_timeout_cmd(        \
286                         wq_head, condition, timeout, cmd1, cmd2);       \
287         __ret;                                                          \
288 })
289
290 #define __wait_event_idle_timeout(wq_head, condition, timeout)          \
291         ___wait_event_idle(wq_head, ___wait_cond_timeout1(condition),   \
292                            0, timeout,                                  \
293                            __ret = schedule_timeout(__ret))
294
295 #define wait_event_idle_timeout(wq_head, condition, timeout)            \
296 ({                                                                      \
297         long __ret = timeout;                                           \
298         might_sleep();                                                  \
299         if (!___wait_cond_timeout1(condition))                          \
300                 __ret = __wait_event_idle_timeout(wq_head, condition,   \
301                                                   timeout);             \
302         __ret;                                                          \
303 })
304
305 #else /* TASK_IDLE */
306 #ifndef wait_event_idle
307 /**
308  * wait_event_idle - wait for a condition without contributing to system load
309  * @wq_head: the waitqueue to wait on
310  * @condition: a C expression for the event to wait for
311  *
312  * The process is put to sleep (TASK_IDLE) until the
313  * @condition evaluates to true.
314  * The @condition is checked each time the waitqueue @wq_head is woken up.
315  *
316  * wake_up() has to be called after changing any variable that could
317  * change the result of the wait condition.
318  *
319  */
320 #define wait_event_idle(wq_head, condition)                             \
321 do {                                                                    \
322         might_sleep();                                                  \
323         if (!(condition))                                               \
324                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0,      \
325                               schedule());                              \
326 } while (0)
327 #endif
328 #ifndef wait_event_idle_exclusive
329 /**
330  * wait_event_idle_exclusive - wait for a condition without contributing to
331  *               system load
332  * @wq_head: the waitqueue to wait on
333  * @condition: a C expression for the event to wait for
334  *
335  * The process is put to sleep (TASK_IDLE) until the
336  * @condition evaluates to true.
337  * The @condition is checked each time the waitqueue @wq_head is woken up.
338  *
339  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
340  * set thus if other processes wait on the same list, when this
341  * process is woken further processes are not considered.
342  *
343  * wake_up() has to be called after changing any variable that could
344  * change the result of the wait condition.
345  *
346  */
347 #define wait_event_idle_exclusive(wq_head, condition)                   \
348 do {                                                                    \
349         might_sleep();                                                  \
350         if (!(condition))                                               \
351                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0,      \
352                               schedule());                              \
353 } while (0)
354 #endif
355 #ifndef wait_event_idle_exclusive_timeout
356 /**
357  * wait_event_idle_exclusive_timeout - sleep without load until a condition
358  *                       becomes true or a timeout elapses
359  * @wq_head: the waitqueue to wait on
360  * @condition: a C expression for the event to wait for
361  * @timeout: timeout, in jiffies
362  *
363  * The process is put to sleep (TASK_IDLE) until the
364  * @condition evaluates to true. The @condition is checked each time
365  * the waitqueue @wq_head is woken up.
366  *
367  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
368  * set thus if other processes wait on the same list, when this
369  * process is woken further processes are not considered.
370  *
371  * wake_up() has to be called after changing any variable that could
372  * change the result of the wait condition.
373  *
374  * Returns:
375  * 0 if the @condition evaluated to %false after the @timeout elapsed,
376  * 1 if the @condition evaluated to %true after the @timeout elapsed,
377  * or the remaining jiffies (at least 1) if the @condition evaluated
378  * to %true before the @timeout elapsed.
379  */
380 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)  \
381 ({                                                                      \
382         long __ret = timeout;                                           \
383         might_sleep();                                                  \
384         if (!___wait_cond_timeout1(condition))                          \
385                 __ret = __wait_event_idle_exclusive_timeout(wq_head,    \
386                                                             condition,  \
387                                                             timeout);   \
388         __ret;                                                          \
389 })
390 #endif
391 #ifndef wait_event_idle_exclusive_timeout_cmd
392 #define __wait_event_idle_exclusive_timeout_cmd(wq_head, condition,     \
393                                                 timeout, cmd1, cmd2)    \
394         ___wait_event(wq_head, ___wait_cond_timeout1(condition),        \
395                       TASK_IDLE, 1, timeout,                            \
396                       cmd1; __ret = schedule_timeout(__ret); cmd2)
397
398 #define wait_event_idle_exclusive_timeout_cmd(wq_head, condition, timeout,\
399                                               cmd1, cmd2)               \
400 ({                                                                      \
401         long __ret = timeout;                                           \
402         if (!___wait_cond_timeout1(condition))                          \
403                 __ret = __wait_event_idle_exclusive_timeout_cmd(        \
404                         wq_head, condition, timeout, cmd1, cmd2);       \
405         __ret;                                                          \
406 })
407 #endif
408
409 #ifndef wait_event_idle_timeout
410
411 #define __wait_event_idle_timeout(wq_head, condition, timeout)          \
412         ___wait_event(wq_head, ___wait_cond_timeout1(condition),        \
413                       TASK_IDLE, 0, timeout,                            \
414                       __ret = schedule_timeout(__ret))
415
416 /**
417  * wait_event_idle_timeout - sleep without load until a condition becomes
418  *                           true or a timeout elapses
419  * @wq_head: the waitqueue to wait on
420  * @condition: a C expression for the event to wait for
421  * @timeout: timeout, in jiffies
422  *
423  * The process is put to sleep (TASK_IDLE) until the
424  * @condition evaluates to true. The @condition is checked each time
425  * the waitqueue @wq_head is woken up.
426  *
427  * wake_up() has to be called after changing any variable that could
428  * change the result of the wait condition.
429  *
430  * Returns:
431  * 0 if the @condition evaluated to %false after the @timeout elapsed,
432  * 1 if the @condition evaluated to %true after the @timeout elapsed,
433  * or the remaining jiffies (at least 1) if the @condition evaluated
434  * to %true before the @timeout elapsed.
435  */
436 #define wait_event_idle_timeout(wq_head, condition, timeout)            \
437 ({                                                                      \
438         long __ret = timeout;                                           \
439         might_sleep();                                                  \
440         if (!___wait_cond_timeout1(condition))                          \
441                 __ret = __wait_event_idle_timeout(wq_head, condition,   \
442                                                   timeout);             \
443         __ret;                                                          \
444 })
445 #endif
446 #endif /* TASK_IDLE */
447
448 /* ___wait_event_lifo is used for lifo exclusive 'idle' waits */
449 #ifdef TASK_NOLOAD
450
451 #define ___wait_event_lifo(wq_head, condition, ret, cmd)                \
452 ({                                                                      \
453         wait_queue_entry_t       __wq_entry;                            \
454         long __ret = ret;       /* explicit shadow */                   \
455                                                                         \
456         init_wait(&__wq_entry);                                         \
457         __wq_entry.flags =  WQ_FLAG_EXCLUSIVE;                          \
458         for (;;) {                                                      \
459                 prepare_to_wait_exclusive_head(&wq_head, &__wq_entry);  \
460                 prepare_to_wait_event(&wq_head, &__wq_entry, TASK_IDLE);\
461                                                                         \
462                 if (condition)                                          \
463                         break;                                          \
464                                                                         \
465                 cmd;                                                    \
466         }                                                               \
467         finish_wait(&wq_head, &__wq_entry);                             \
468         __ret;                                                          \
469 })
470 #else
471 #define ___wait_event_lifo(wq_head, condition, ret, cmd)                \
472 ({                                                                      \
473         wait_queue_entry_t __wq_entry;                                  \
474         unsigned long flags;                                            \
475         long __ret = ret;       /* explicit shadow */                   \
476         sigset_t __old_blocked;                                         \
477                                                                         \
478         cfs_block_sigsinv(0, &__old_blocked);                           \
479         init_wait(&__wq_entry);                                         \
480         __wq_entry.flags = WQ_FLAG_EXCLUSIVE;                           \
481         for (;;) {                                                      \
482                 prepare_to_wait_exclusive_head(&wq_head, &__wq_entry);  \
483                 prepare_to_wait_event(&wq_head, &__wq_entry,            \
484                                       TASK_INTERRUPTIBLE);              \
485                                                                         \
486                 if (condition)                                          \
487                         break;                                          \
488                 /* See justification in ___wait_event_idle */           \
489                 if (signal_pending(current)) {                          \
490                         spin_lock_irqsave(&current->sighand->siglock,   \
491                                           flags);                       \
492                         clear_tsk_thread_flag(current, TIF_SIGPENDING); \
493                         spin_unlock_irqrestore(&current->sighand->siglock,\
494                                                flags);                  \
495                 }                                                       \
496                 cmd;                                                    \
497         }                                                               \
498         cfs_restore_sigs(&__old_blocked);                               \
499         finish_wait(&wq_head, &__wq_entry);                             \
500         __ret;                                                          \
501 })
502 #endif
503
504 #define wait_event_idle_exclusive_lifo(wq_head, condition)              \
505 do {                                                                    \
506         might_sleep();                                                  \
507         if (!(condition))                                               \
508                 ___wait_event_lifo(wq_head, condition, 0, schedule());  \
509 } while (0)
510
511 #define __wait_event_idle_lifo_timeout(wq_head, condition, timeout)     \
512         ___wait_event_lifo(wq_head, ___wait_cond_timeout1(condition),   \
513                            timeout,                                     \
514                            __ret = schedule_timeout(__ret))
515
516 #define wait_event_idle_exclusive_lifo_timeout(wq_head, condition, timeout)\
517 ({                                                                      \
518         long __ret = timeout;                                           \
519         might_sleep();                                                  \
520         if (!___wait_cond_timeout1(condition))                          \
521                 __ret = __wait_event_idle_lifo_timeout(wq_head,         \
522                                                        condition,       \
523                                                        timeout);        \
524         __ret;                                                          \
525 })
526
527 /* l_wait_event_abortable() is a bit like wait_event_killable()
528  * except there is a fixed set of signals which will abort:
529  * LUSTRE_FATAL_SIGS
530  */
531 #define LUSTRE_FATAL_SIGS                                        \
532         (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGTERM) | \
533          sigmask(SIGQUIT) | sigmask(SIGALRM))
534
535 #define l_wait_event_abortable(wq, condition)                           \
536 ({                                                                      \
537         sigset_t __new_blocked, __old_blocked;                          \
538         int __ret = 0;                                                  \
539         siginitsetinv(&__new_blocked, LUSTRE_FATAL_SIGS);               \
540         sigprocmask(SIG_BLOCK, &__new_blocked, &__old_blocked);         \
541         __ret = wait_event_interruptible(wq, condition);                \
542         sigprocmask(SIG_SETMASK, &__old_blocked, NULL);                 \
543         __ret;                                                          \
544 })
545
546 #define l_wait_event_abortable_timeout(wq, condition, timeout)          \
547 ({                                                                      \
548         sigset_t __new_blocked, __old_blocked;                          \
549         int __ret = 0;                                                  \
550         siginitsetinv(&__new_blocked, LUSTRE_FATAL_SIGS);               \
551         sigprocmask(SIG_BLOCK, &__new_blocked, &__old_blocked);         \
552         __ret = wait_event_interruptible_timeout(wq, condition, timeout);\
553         sigprocmask(SIG_SETMASK, &__old_blocked, NULL);                 \
554         __ret;                                                          \
555 })
556
557 #define l_wait_event_abortable_exclusive(wq, condition)                 \
558 ({                                                                      \
559         sigset_t __new_blocked, __old_blocked;                          \
560         int __ret = 0;                                                  \
561         siginitsetinv(&__new_blocked, LUSTRE_FATAL_SIGS);               \
562         sigprocmask(SIG_BLOCK, &__new_blocked, &__old_blocked);         \
563         __ret = wait_event_interruptible_exclusive(wq, condition);      \
564         sigprocmask(SIG_SETMASK, &__old_blocked, NULL);                 \
565         __ret;                                                          \
566 })
567
568 #endif /* __LICBFS_LINUX_WAIT_BIT_H */