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         long __ret = ret;       /* explicit shadow */                   \
 210         sigset_t __blocked;                                             \
 211                                                                         \
 212         __blocked = cfs_block_sigsinv(0);                               \
 213         init_wait(&__wq_entry);                                         \
 214         if (exclusive)                                                  \
 215                 __wq_entry.flags = WQ_FLAG_EXCLUSIVE;                   \
 216         for (;;) {                                                      \
 217                 prepare_to_wait_event(&wq_head,                         \
 218                                    &__wq_entry,                         \
 219                                    TASK_INTERRUPTIBLE);                 \
 220                                                                         \
 221                 if (condition)                                          \
 222                         break;                                          \
 223                 /* See justification in __l_wait_event */               \
 224                 if (signal_pending(current))                            \
 225                         cfs_clear_sigpending();                         \
 226                                                                         \
 227                 cmd;                                                    \
 228         }                                                               \
 229         finish_wait(&wq_head, &__wq_entry);                             \
 230         cfs_restore_sigs(__blocked);                                    \
 231         __ret;                                                          \
 232 })
 233
 234 #define wait_event_idle(wq_head, condition)                             \
 235 do {                                                                    \
 236         might_sleep();                                                  \
 237         if (!(condition))                                               \
 238                 ___wait_event_idle(wq_head, condition, 0, 0, schedule());\
 239 } while (0)
 240
 241 #define wait_event_idle_exclusive(wq_head, condition)                   \
 242 do {                                                                    \
 243         might_sleep();                                                  \
 244         if (!(condition))                                               \
 245                 ___wait_event_idle(wq_head, condition, 1, 0, schedule());\
 246 } while (0)
 247
 248 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)\
 249         ___wait_event_idle(wq_head, ___wait_cond_timeout1(condition),   \
 250                            1, timeout,                                  \
 251                            __ret = schedule_timeout(__ret))
 252
 253 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)  \
 254 ({                                                                      \
 255         long __ret = timeout;                                           \
 256         might_sleep();                                                  \
 257         if (!___wait_cond_timeout1(condition))                          \
 258                 __ret = __wait_event_idle_exclusive_timeout(            \
 259                         wq_head, condition, timeout);                   \
 260         __ret;                                                          \
 261 })
 262
 263 #define __wait_event_idle_exclusive_timeout_cmd(wq_head, condition,     \
 264                                                 timeout, cmd1, cmd2)    \
 265         ___wait_event_idle(wq_head, ___wait_cond_timeout1(condition),   \
 266                            1, timeout,                                  \
 267                            cmd1; __ret = schedule_timeout(__ret); cmd2)
 268
 269 #define wait_event_idle_exclusive_timeout_cmd(wq_head, condition, timeout,\
 270                                               cmd1, cmd2)               \
 271 ({                                                                      \
 272         long __ret = timeout;                                           \
 273         might_sleep();                                                  \
 274         if (!___wait_cond_timeout1(condition))                          \
 275                 __ret = __wait_event_idle_exclusive_timeout_cmd(        \
 276                         wq_head, condition, timeout, cmd1, cmd2);       \
 277         __ret;                                                          \
 278 })
 279
 280 #define __wait_event_idle_timeout(wq_head, condition, timeout)          \
 281         ___wait_event_idle(wq_head, ___wait_cond_timeout1(condition),   \
 282                            0, timeout,                                  \
 283                            __ret = schedule_timeout(__ret))
 284
 285 #define wait_event_idle_timeout(wq_head, condition, timeout)            \
 286 ({                                                                      \
 287         long __ret = timeout;                                           \
 288         might_sleep();                                                  \
 289         if (!___wait_cond_timeout1(condition))                          \
 290                 __ret = __wait_event_idle_timeout(wq_head, condition,   \
 291                                                   timeout);             \
 292         __ret;                                                          \
 293 })
 294
 295 #else /* TASK_IDLE */
 296 #ifndef wait_event_idle
 297 /**
 298  * wait_event_idle - wait for a condition without contributing to system load
 299  * @wq_head: the waitqueue to wait on
 300  * @condition: a C expression for the event to wait for
 301  *
 302  * The process is put to sleep (TASK_IDLE) until the
 303  * @condition evaluates to true.
 304  * The @condition is checked each time the waitqueue @wq_head is woken up.
 305  *
 306  * wake_up() has to be called after changing any variable that could
 307  * change the result of the wait condition.
 308  *
 309  */
 310 #define wait_event_idle(wq_head, condition)                             \
 311 do {                                                                    \
 312         might_sleep();                                                  \
 313         if (!(condition))                                               \
 314                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0,      \
 315                               schedule());                              \
 316 } while (0)
 317 #endif
 318 #ifndef wait_event_idle_exclusive
 319 /**
 320  * wait_event_idle_exclusive - wait for a condition without contributing to
 321  *               system load
 322  * @wq_head: the waitqueue to wait on
 323  * @condition: a C expression for the event to wait for
 324  *
 325  * The process is put to sleep (TASK_IDLE) until the
 326  * @condition evaluates to true.
 327  * The @condition is checked each time the waitqueue @wq_head is woken up.
 328  *
 329  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 330  * set thus if other processes wait on the same list, when this
 331  * process is woken further processes are not considered.
 332  *
 333  * wake_up() has to be called after changing any variable that could
 334  * change the result of the wait condition.
 335  *
 336  */
 337 #define wait_event_idle_exclusive(wq_head, condition)                   \
 338 do {                                                                    \
 339         might_sleep();                                                  \
 340         if (!(condition))                                               \
 341                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0,      \
 342                               schedule());                              \
 343 } while (0)
 344 #endif
 345 #ifndef wait_event_idle_exclusive_timeout
 346 /**
 347  * wait_event_idle_exclusive_timeout - sleep without load until a condition
 348  *                       becomes true or a timeout elapses
 349  * @wq_head: the waitqueue to wait on
 350  * @condition: a C expression for the event to wait for
 351  * @timeout: timeout, in jiffies
 352  *
 353  * The process is put to sleep (TASK_IDLE) until the
 354  * @condition evaluates to true. The @condition is checked each time
 355  * the waitqueue @wq_head is woken up.
 356  *
 357  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 358  * set thus if other processes wait on the same list, when this
 359  * process is woken further processes are not considered.
 360  *
 361  * wake_up() has to be called after changing any variable that could
 362  * change the result of the wait condition.
 363  *
 364  * Returns:
 365  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 366  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 367  * or the remaining jiffies (at least 1) if the @condition evaluated
 368  * to %true before the @timeout elapsed.
 369  */
 370 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)  \
 371 ({                                                                      \
 372         long __ret = timeout;                                           \
 373         might_sleep();                                                  \
 374         if (!___wait_cond_timeout1(condition))                          \
 375                 __ret = __wait_event_idle_exclusive_timeout(wq_head,    \
 376                                                             condition,  \
 377                                                             timeout);   \
 378         __ret;                                                          \
 379 })
 380 #endif
 381 #ifndef wait_event_idle_exclusive_timeout_cmd
 382 #define __wait_event_idle_exclusive_timeout_cmd(wq_head, condition,     \
 383                                                 timeout, cmd1, cmd2)    \
 384         ___wait_event(wq_head, ___wait_cond_timeout1(condition),        \
 385                       TASK_IDLE, 1, timeout,                            \
 386                       cmd1; __ret = schedule_timeout(__ret); cmd2)
 387
 388 #define wait_event_idle_exclusive_timeout_cmd(wq_head, condition, timeout,\
 389                                               cmd1, cmd2)               \
 390 ({                                                                      \
 391         long __ret = timeout;                                           \
 392         might_sleep();                                                  \
 393         if (!___wait_cond_timeout1(condition))                          \
 394                 __ret = __wait_event_idle_exclusive_timeout_cmd(        \
 395                         wq_head, condition, timeout, cmd1, cmd2);       \
 396         __ret;                                                          \
 397 })
 398 #endif
 399
 400 #ifndef wait_event_idle_timeout
 401
 402 #define __wait_event_idle_timeout(wq_head, condition, timeout)          \
 403         ___wait_event(wq_head, ___wait_cond_timeout1(condition),        \
 404                       TASK_IDLE, 0, timeout,                            \
 405                       __ret = schedule_timeout(__ret))
 406
 407 /**
 408  * wait_event_idle_timeout - sleep without load until a condition becomes
 409  *                           true or a timeout elapses
 410  * @wq_head: the waitqueue to wait on
 411  * @condition: a C expression for the event to wait for
 412  * @timeout: timeout, in jiffies
 413  *
 414  * The process is put to sleep (TASK_IDLE) until the
 415  * @condition evaluates to true. The @condition is checked each time
 416  * the waitqueue @wq_head is woken up.
 417  *
 418  * wake_up() has to be called after changing any variable that could
 419  * change the result of the wait condition.
 420  *
 421  * Returns:
 422  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 423  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 424  * or the remaining jiffies (at least 1) if the @condition evaluated
 425  * to %true before the @timeout elapsed.
 426  */
 427 #define wait_event_idle_timeout(wq_head, condition, timeout)            \
 428 ({                                                                      \
 429         long __ret = timeout;                                           \
 430         might_sleep();                                                  \
 431         if (!___wait_cond_timeout1(condition))                          \
 432                 __ret = __wait_event_idle_timeout(wq_head, condition,   \
 433                                                   timeout);             \
 434         __ret;                                                          \
 435 })
 436 #endif
 437 #endif /* TASK_IDLE */
 438
 439 /* ___wait_event_lifo is used for lifo exclusive 'idle' waits */
 440 #ifdef TASK_NOLOAD
 441
 442 #define ___wait_event_lifo(wq_head, condition, ret, cmd)                \
 443 ({                                                                      \
 444         wait_queue_entry_t       __wq_entry;                            \
 445         long __ret = ret;       /* explicit shadow */                   \
 446                                                                         \
 447         init_wait(&__wq_entry);                                         \
 448         __wq_entry.flags =  WQ_FLAG_EXCLUSIVE;                          \
 449         for (;;) {                                                      \
 450                 prepare_to_wait_exclusive_head(&wq_head, &__wq_entry);  \
 451                 prepare_to_wait_event(&wq_head, &__wq_entry, TASK_IDLE);\
 452                                                                         \
 453                 if (condition)                                          \
 454                         break;                                          \
 455                                                                         \
 456                 cmd;                                                    \
 457         }                                                               \
 458         finish_wait(&wq_head, &__wq_entry);                             \
 459         __ret;                                                          \
 460 })
 461 #else
 462 #define ___wait_event_lifo(wq_head, condition, ret, cmd)                \
 463 ({                                                                      \
 464         wait_queue_entry_t __wq_entry;                                  \
 465         long __ret = ret;       /* explicit shadow */                   \
 466         sigset_t __blocked;                                             \
 467                                                                         \
 468         __blocked = cfs_block_sigsinv(0);                               \
 469         init_wait(&__wq_entry);                                         \
 470         __wq_entry.flags = WQ_FLAG_EXCLUSIVE;                           \
 471         for (;;) {                                                      \
 472                 prepare_to_wait_exclusive_head(&wq_head, &__wq_entry);  \
 473                 prepare_to_wait_event(&wq_head, &__wq_entry,            \
 474                                       TASK_INTERRUPTIBLE);              \
 475                                                                         \
 476                 if (condition)                                          \
 477                         break;                                          \
 478                 /* See justification in __l_wait_event */               \
 479                 if (signal_pending(current))                            \
 480                         cfs_clear_sigpending();                         \
 481                                                                         \
 482                 cmd;                                                    \
 483         }                                                               \
 484         cfs_restore_sigs(__blocked);                                    \
 485         finish_wait(&wq_head, &__wq_entry);                             \
 486         __ret;                                                          \
 487 })
 488 #endif
 489
 490 #define wait_event_idle_exclusive_lifo(wq_head, condition)              \
 491 do {                                                                    \
 492         might_sleep();                                                  \
 493         if (!(condition))                                               \
 494                 ___wait_event_lifo(wq_head, condition, 0, schedule());  \
 495 } while (0)
 496
 497 #define __wait_event_idle_lifo_timeout(wq_head, condition, timeout)     \
 498         ___wait_event_lifo(wq_head, ___wait_cond_timeout1(condition),   \
 499                            timeout,                                     \
 500                            __ret = schedule_timeout(__ret))
 501
 502 #define wait_event_idle_exclusive_lifo_timeout(wq_head, condition, timeout)\
 503 ({                                                                      \
 504         long __ret = timeout;                                           \
 505         might_sleep();                                                  \
 506         if (!___wait_cond_timeout1(condition))                          \
 507                 __ret = __wait_event_idle_lifo_timeout(wq_head,         \
 508                                                        condition,       \
 509                                                        timeout);        \
 510         __ret;                                                          \
 511 })
 512
 513 /* l_wait_event_abortable() is a bit like wait_event_killable()
 514  * except there is a fixed set of signals which will abort:
 515  * LUSTRE_FATAL_SIGS
 516  */
 517 #define LUSTRE_FATAL_SIGS                                        \
 518         (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGTERM) | \
 519          sigmask(SIGQUIT) | sigmask(SIGALRM))
 520
 521 #define l_wait_event_abortable(wq, condition)                           \
 522 ({                                                                      \
 523         sigset_t __new_blocked, __old_blocked;                          \
 524         int __ret = 0;                                                  \
 525         siginitsetinv(&__new_blocked, LUSTRE_FATAL_SIGS);               \
 526         sigprocmask(SIG_BLOCK, &__new_blocked, &__old_blocked);         \
 527         __ret = wait_event_interruptible(wq, condition);                \
 528         sigprocmask(SIG_SETMASK, &__old_blocked, NULL);                 \
 529         __ret;                                                          \
 530 })
 531
 532 #define l_wait_event_abortable_timeout(wq, condition, timeout)          \
 533 ({                                                                      \
 534         sigset_t __new_blocked, __old_blocked;                          \
 535         int __ret = 0;                                                  \
 536         siginitsetinv(&__new_blocked, LUSTRE_FATAL_SIGS);               \
 537         sigprocmask(SIG_BLOCK, &__new_blocked, &__old_blocked);         \
 538         __ret = wait_event_interruptible_timeout(wq, condition, timeout);\
 539         sigprocmask(SIG_SETMASK, &__old_blocked, NULL);                 \
 540         __ret;                                                          \
 541 })
 542
 543 #define l_wait_event_abortable_exclusive(wq, condition)                 \
 544 ({                                                                      \
 545         sigset_t __new_blocked, __old_blocked;                          \
 546         int __ret = 0;                                                  \
 547         siginitsetinv(&__new_blocked, LUSTRE_FATAL_SIGS);               \
 548         sigprocmask(SIG_BLOCK, &__new_blocked, &__old_blocked);         \
 549         __ret = wait_event_interruptible_exclusive(wq, condition);      \
 550         sigprocmask(SIG_SETMASK, &__old_blocked, NULL);                 \
 551         __ret;                                                          \
 552 })
 553
 554 #endif /* __LICBFS_LINUX_WAIT_BIT_H */