sys/kern/subr_taskqueue.c

   1 /*-
   2  * Copyright (c) 2000 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/bus.h>
  33 #include <sys/interrupt.h>
  34 #include <sys/kernel.h>
  35 #include <sys/kthread.h>
  36 #include <sys/limits.h>
  37 #include <sys/lock.h>
  38 #include <sys/malloc.h>
  39 #include <sys/mutex.h>
  40 #include <sys/proc.h>
  41 #include <sys/sched.h>
  42 #include <sys/taskqueue.h>
  43 #include <sys/unistd.h>
  44 #include <machine/stdarg.h>
  45
  46 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  47 static void     *taskqueue_giant_ih;
  48 static void     *taskqueue_ih;
  49 static void      taskqueue_fast_enqueue(void *);
  50 static void      taskqueue_swi_enqueue(void *);
  51 static void      taskqueue_swi_giant_enqueue(void *);
  52
  53 struct taskqueue_busy {
  54         struct task     *tb_running;
  55         TAILQ_ENTRY(taskqueue_busy) tb_link;
  56 };
  57
  58 struct taskqueue {
  59         STAILQ_HEAD(, task)     tq_queue;
  60         taskqueue_enqueue_fn    tq_enqueue;
  61         void                    *tq_context;
  62         TAILQ_HEAD(, taskqueue_busy) tq_active;
  63         struct mtx              tq_mutex;
  64         struct thread           **tq_threads;
  65         int                     tq_tcount;
  66         int                     tq_spin;
  67         int                     tq_flags;
  68         int                     tq_callouts;
  69         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  70         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  71 };
  72
  73 #define TQ_FLAGS_ACTIVE         (1 << 0)
  74 #define TQ_FLAGS_BLOCKED        (1 << 1)
  75 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  76
  77 #define DT_CALLOUT_ARMED        (1 << 0)
  78 #define DT_DRAIN_IN_PROGRESS    (1 << 1)
  79
  80 #define TQ_LOCK(tq)                                                     \
  81         do {                                                            \
  82                 if ((tq)->tq_spin)                                      \
  83                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  84                 else                                                    \
  85                         mtx_lock(&(tq)->tq_mutex);                      \
  86         } while (0)
  87 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  88
  89 #define TQ_UNLOCK(tq)                                                   \
  90         do {                                                            \
  91                 if ((tq)->tq_spin)                                      \
  92                         mtx_unlock_spin(&(tq)->tq_mutex);               \
  93                 else                                                    \
  94                         mtx_unlock(&(tq)->tq_mutex);                    \
  95         } while (0)
  96 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
  97
  98 void
  99 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 100     int priority, task_fn_t func, void *context)
 101 {
 102
 103         TASK_INIT(&timeout_task->t, priority, func, context);
 104         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 105             CALLOUT_RETURNUNLOCKED);
 106         timeout_task->q = queue;
 107         timeout_task->f = 0;
 108 }
 109
 110 static __inline int
 111 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
 112     int t)
 113 {
 114         if (tq->tq_spin)
 115                 return (msleep_spin(p, m, wm, t));
 116         return (msleep(p, m, pri, wm, t));
 117 }
 118
 119 static struct taskqueue *
 120 _taskqueue_create(const char *name __unused, int mflags,
 121                  taskqueue_enqueue_fn enqueue, void *context,
 122                  int mtxflags, const char *mtxname)
 123 {
 124         struct taskqueue *queue;
 125
 126         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 127         if (!queue)
 128                 return NULL;
 129
 130         STAILQ_INIT(&queue->tq_queue);
 131         TAILQ_INIT(&queue->tq_active);
 132         queue->tq_enqueue = enqueue;
 133         queue->tq_context = context;
 134         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 135         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 136         if (enqueue == taskqueue_fast_enqueue ||
 137             enqueue == taskqueue_swi_enqueue ||
 138             enqueue == taskqueue_swi_giant_enqueue ||
 139             enqueue == taskqueue_thread_enqueue)
 140                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 141         mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
 142
 143         return queue;
 144 }
 145
 146 struct taskqueue *
 147 taskqueue_create(const char *name, int mflags,
 148                  taskqueue_enqueue_fn enqueue, void *context)
 149 {
 150         return _taskqueue_create(name, mflags, enqueue, context,
 151                         MTX_DEF, "taskqueue");
 152 }
 153
 154 void
 155 taskqueue_set_callback(struct taskqueue *queue,
 156     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 157     void *context)
 158 {
 159
 160         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 161             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 162             ("Callback type %d not valid, must be %d-%d", cb_type,
 163             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 164         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 165             ("Re-initialization of taskqueue callback?"));
 166
 167         queue->tq_callbacks[cb_type] = callback;
 168         queue->tq_cb_contexts[cb_type] = context;
 169 }
 170
 171 /*
 172  * Signal a taskqueue thread to terminate.
 173  */
 174 static void
 175 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 176 {
 177
 178         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 179                 wakeup(tq);
 180                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
 181         }
 182 }
 183
 184 void
 185 taskqueue_free(struct taskqueue *queue)
 186 {
 187
 188         TQ_LOCK(queue);
 189         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 190         taskqueue_terminate(queue->tq_threads, queue);
 191         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
 192         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 193         mtx_destroy(&queue->tq_mutex);
 194         free(queue->tq_threads, M_TASKQUEUE);
 195         free(queue, M_TASKQUEUE);
 196 }
 197
 198 static int
 199 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 200 {
 201         struct task *ins;
 202         struct task *prev;
 203
 204         /*
 205          * Count multiple enqueues.
 206          */
 207         if (task->ta_pending) {
 208                 if (task->ta_pending < USHRT_MAX)
 209                         task->ta_pending++;
 210                 TQ_UNLOCK(queue);
 211                 return (0);
 212         }
 213
 214         /*
 215          * Optimise the case when all tasks have the same priority.
 216          */
 217         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 218         if (!prev || prev->ta_priority >= task->ta_priority) {
 219                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 220         } else {
 221                 prev = NULL;
 222                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 223                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 224                         if (ins->ta_priority < task->ta_priority)
 225                                 break;
 226
 227                 if (prev)
 228                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 229                 else
 230                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 231         }
 232
 233         task->ta_pending = 1;
 234         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 235                 TQ_UNLOCK(queue);
 236         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 237                 queue->tq_enqueue(queue->tq_context);
 238         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 239                 TQ_UNLOCK(queue);
 240
 241         /* Return with lock released. */
 242         return (0);
 243 }
 244 int
 245 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 246 {
 247         int res;
 248
 249         TQ_LOCK(queue);
 250         res = taskqueue_enqueue_locked(queue, task);
 251         /* The lock is released inside. */
 252
 253         return (res);
 254 }
 255
 256 static void
 257 taskqueue_timeout_func(void *arg)
 258 {
 259         struct taskqueue *queue;
 260         struct timeout_task *timeout_task;
 261
 262         timeout_task = arg;
 263         queue = timeout_task->q;
 264         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 265         timeout_task->f &= ~DT_CALLOUT_ARMED;
 266         queue->tq_callouts--;
 267         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 268         /* The lock is released inside. */
 269 }
 270
 271 int
 272 taskqueue_enqueue_timeout(struct taskqueue *queue,
 273     struct timeout_task *timeout_task, int ticks)
 274 {
 275         int res;
 276
 277         TQ_LOCK(queue);
 278         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 279             ("Migrated queue"));
 280         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 281         timeout_task->q = queue;
 282         res = timeout_task->t.ta_pending;
 283         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
 284                 /* Do nothing */
 285                 TQ_UNLOCK(queue);
 286                 res = -1;
 287         } else if (ticks == 0) {
 288                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 289                 /* The lock is released inside. */
 290         } else {
 291                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 292                         res++;
 293                 } else {
 294                         queue->tq_callouts++;
 295                         timeout_task->f |= DT_CALLOUT_ARMED;
 296                         if (ticks < 0)
 297                                 ticks = -ticks; /* Ignore overflow. */
 298                 }
 299                 if (ticks > 0) {
 300                         callout_reset(&timeout_task->c, ticks,
 301                             taskqueue_timeout_func, timeout_task);
 302                 }
 303                 TQ_UNLOCK(queue);
 304         }
 305         return (res);
 306 }
 307
 308 static void
 309 taskqueue_drain_running(struct taskqueue *queue)
 310 {
 311
 312         while (!TAILQ_EMPTY(&queue->tq_active))
 313                 TQ_SLEEP(queue, &queue->tq_active, &queue->tq_mutex,
 314                     PWAIT, "-", 0);
 315 }
 316
 317 void
 318 taskqueue_block(struct taskqueue *queue)
 319 {
 320
 321         TQ_LOCK(queue);
 322         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 323         TQ_UNLOCK(queue);
 324 }
 325
 326 void
 327 taskqueue_unblock(struct taskqueue *queue)
 328 {
 329
 330         TQ_LOCK(queue);
 331         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 332         if (!STAILQ_EMPTY(&queue->tq_queue))
 333                 queue->tq_enqueue(queue->tq_context);
 334         TQ_UNLOCK(queue);
 335 }
 336
 337 static void
 338 taskqueue_run_locked(struct taskqueue *queue)
 339 {
 340         struct taskqueue_busy tb;
 341         struct task *task;
 342         int pending;
 343
 344         TQ_ASSERT_LOCKED(queue);
 345         tb.tb_running = NULL;
 346         TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
 347
 348         while (STAILQ_FIRST(&queue->tq_queue)) {
 349                 /*
 350                  * Carefully remove the first task from the queue and
 351                  * zero its pending count.
 352                  */
 353                 task = STAILQ_FIRST(&queue->tq_queue);
 354                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 355                 pending = task->ta_pending;
 356                 task->ta_pending = 0;
 357                 tb.tb_running = task;
 358                 TQ_UNLOCK(queue);
 359
 360                 task->ta_func(task->ta_context, pending);
 361
 362                 TQ_LOCK(queue);
 363                 tb.tb_running = NULL;
 364                 wakeup(task);
 365         }
 366         TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
 367         if (TAILQ_EMPTY(&queue->tq_active))
 368                 wakeup(&queue->tq_active);
 369 }
 370
 371 void
 372 taskqueue_run(struct taskqueue *queue)
 373 {
 374
 375         TQ_LOCK(queue);
 376         taskqueue_run_locked(queue);
 377         TQ_UNLOCK(queue);
 378 }
 379
 380 static int
 381 task_is_running(struct taskqueue *queue, struct task *task)
 382 {
 383         struct taskqueue_busy *tb;
 384
 385         TQ_ASSERT_LOCKED(queue);
 386         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
 387                 if (tb->tb_running == task)
 388                         return (1);
 389         }
 390         return (0);
 391 }
 392
 393 static int
 394 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 395     u_int *pendp)
 396 {
 397
 398         if (task->ta_pending > 0)
 399                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 400         if (pendp != NULL)
 401                 *pendp = task->ta_pending;
 402         task->ta_pending = 0;
 403         return (task_is_running(queue, task) ? EBUSY : 0);
 404 }
 405
 406 int
 407 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 408 {
 409         int error;
 410
 411         TQ_LOCK(queue);
 412         error = taskqueue_cancel_locked(queue, task, pendp);
 413         TQ_UNLOCK(queue);
 414
 415         return (error);
 416 }
 417
 418 int
 419 taskqueue_cancel_timeout(struct taskqueue *queue,
 420     struct timeout_task *timeout_task, u_int *pendp)
 421 {
 422         u_int pending, pending1;
 423         int error;
 424
 425         TQ_LOCK(queue);
 426         pending = !!callout_stop(&timeout_task->c);
 427         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 428         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 429                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 430                 queue->tq_callouts--;
 431         }
 432         TQ_UNLOCK(queue);
 433
 434         if (pendp != NULL)
 435                 *pendp = pending + pending1;
 436         return (error);
 437 }
 438
 439 void
 440 taskqueue_drain(struct taskqueue *queue, struct task *task)
 441 {
 442
 443         if (!queue->tq_spin)
 444                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 445
 446         TQ_LOCK(queue);
 447         while (task->ta_pending != 0 || task_is_running(queue, task))
 448                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 449         TQ_UNLOCK(queue);
 450 }
 451
 452 void
 453 taskqueue_drain_all(struct taskqueue *queue)
 454 {
 455         struct task *task;
 456
 457         if (!queue->tq_spin)
 458                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 459
 460         TQ_LOCK(queue);
 461         task = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 462         while (task != NULL && task->ta_pending != 0) {
 463                 struct task *oldtask;
 464                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 465                 /*
 466                  * While we were asleeep the last entry may have been freed.
 467                  * We need to check if it's still even in the queue.
 468                  * Not perfect, but it's better than referencing bad memory.
 469                  * first guess is the current 'end of queue' but if a new
 470                  * item has been added we need to take the expensive path
 471                  * Better fix in 11.
 472                  */
 473                 oldtask = task;
 474                 if (oldtask !=
 475                     (task = STAILQ_LAST(&queue->tq_queue, task, ta_link))) {
 476                         STAILQ_FOREACH(task, &queue->tq_queue, ta_link) {
 477                                 if (task == oldtask)
 478                                         break;
 479                         }
 480                 }
 481         }
 482         taskqueue_drain_running(queue);
 483         KASSERT(STAILQ_EMPTY(&queue->tq_queue),
 484             ("taskqueue queue is not empty after draining"));
 485         TQ_UNLOCK(queue);
 486 }
 487
 488 void
 489 taskqueue_drain_timeout(struct taskqueue *queue,
 490     struct timeout_task *timeout_task)
 491 {
 492
 493         /*
 494          * Set flag to prevent timer from re-starting during drain:
 495          */
 496         TQ_LOCK(queue);
 497         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 498             ("Drain already in progress"));
 499         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 500         TQ_UNLOCK(queue);
 501
 502         callout_drain(&timeout_task->c);
 503         taskqueue_drain(queue, &timeout_task->t);
 504
 505         /*
 506          * Clear flag to allow timer to re-start:
 507          */
 508         TQ_LOCK(queue);
 509         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 510         TQ_UNLOCK(queue);
 511 }
 512
 513 static void
 514 taskqueue_swi_enqueue(void *context)
 515 {
 516         swi_sched(taskqueue_ih, 0);
 517 }
 518
 519 static void
 520 taskqueue_swi_run(void *dummy)
 521 {
 522         taskqueue_run(taskqueue_swi);
 523 }
 524
 525 static void
 526 taskqueue_swi_giant_enqueue(void *context)
 527 {
 528         swi_sched(taskqueue_giant_ih, 0);
 529 }
 530
 531 static void
 532 taskqueue_swi_giant_run(void *dummy)
 533 {
 534         taskqueue_run(taskqueue_swi_giant);
 535 }
 536
 537 int
 538 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 539                         const char *name, ...)
 540 {
 541         va_list ap;
 542         struct thread *td;
 543         struct taskqueue *tq;
 544         int i, error;
 545         char ktname[MAXCOMLEN + 1];
 546
 547         if (count <= 0)
 548                 return (EINVAL);
 549
 550         tq = *tqp;
 551
 552         va_start(ap, name);
 553         vsnprintf(ktname, sizeof(ktname), name, ap);
 554         va_end(ap);
 555
 556         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 557             M_NOWAIT | M_ZERO);
 558         if (tq->tq_threads == NULL) {
 559                 printf("%s: no memory for %s threads\n", __func__, ktname);
 560                 return (ENOMEM);
 561         }
 562
 563         for (i = 0; i < count; i++) {
 564                 if (count == 1)
 565                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 566                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 567                 else
 568                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 569                             &tq->tq_threads[i], RFSTOPPED, 0,
 570                             "%s_%d", ktname, i);
 571                 if (error) {
 572                         /* should be ok to continue, taskqueue_free will dtrt */
 573                         printf("%s: kthread_add(%s): error %d", __func__,
 574                             ktname, error);
 575                         tq->tq_threads[i] = NULL;               /* paranoid */
 576                 } else
 577                         tq->tq_tcount++;
 578         }
 579         for (i = 0; i < count; i++) {
 580                 if (tq->tq_threads[i] == NULL)
 581                         continue;
 582                 td = tq->tq_threads[i];
 583                 thread_lock(td);
 584                 sched_prio(td, pri);
 585                 sched_add(td, SRQ_BORING);
 586                 thread_unlock(td);
 587         }
 588
 589         return (0);
 590 }
 591
 592 static inline void
 593 taskqueue_run_callback(struct taskqueue *tq,
 594     enum taskqueue_callback_type cb_type)
 595 {
 596         taskqueue_callback_fn tq_callback;
 597
 598         TQ_ASSERT_UNLOCKED(tq);
 599         tq_callback = tq->tq_callbacks[cb_type];
 600         if (tq_callback != NULL)
 601                 tq_callback(tq->tq_cb_contexts[cb_type]);
 602 }
 603
 604 void
 605 taskqueue_thread_loop(void *arg)
 606 {
 607         struct taskqueue **tqp, *tq;
 608
 609         tqp = arg;
 610         tq = *tqp;
 611         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 612         TQ_LOCK(tq);
 613         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 614                 taskqueue_run_locked(tq);
 615                 /*
 616                  * Because taskqueue_run() can drop tq_mutex, we need to
 617                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 618                  * meantime, which means we missed a wakeup.
 619                  */
 620                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 621                         break;
 622                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 623         }
 624         taskqueue_run_locked(tq);
 625
 626         /*
 627          * This thread is on its way out, so just drop the lock temporarily
 628          * in order to call the shutdown callback.  This allows the callback
 629          * to look at the taskqueue, even just before it dies.
 630          */
 631         TQ_UNLOCK(tq);
 632         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 633         TQ_LOCK(tq);
 634
 635         /* rendezvous with thread that asked us to terminate */
 636         tq->tq_tcount--;
 637         wakeup_one(tq->tq_threads);
 638         TQ_UNLOCK(tq);
 639         kthread_exit();
 640 }
 641
 642 void
 643 taskqueue_thread_enqueue(void *context)
 644 {
 645         struct taskqueue **tqp, *tq;
 646
 647         tqp = context;
 648         tq = *tqp;
 649
 650         wakeup_one(tq);
 651 }
 652
 653 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 654                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 655                      INTR_MPSAFE, &taskqueue_ih));
 656
 657 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 658                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 659                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 660
 661 TASKQUEUE_DEFINE_THREAD(thread);
 662
 663 struct taskqueue *
 664 taskqueue_create_fast(const char *name, int mflags,
 665                  taskqueue_enqueue_fn enqueue, void *context)
 666 {
 667         return _taskqueue_create(name, mflags, enqueue, context,
 668                         MTX_SPIN, "fast_taskqueue");
 669 }
 670
 671 /* NB: for backwards compatibility */
 672 int
 673 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
 674 {
 675         return taskqueue_enqueue(queue, task);
 676 }
 677
 678 static void     *taskqueue_fast_ih;
 679
 680 static void
 681 taskqueue_fast_enqueue(void *context)
 682 {
 683         swi_sched(taskqueue_fast_ih, 0);
 684 }
 685
 686 static void
 687 taskqueue_fast_run(void *dummy)
 688 {
 689         taskqueue_run(taskqueue_fast);
 690 }
 691
 692 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 693         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 694         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 695
 696 int
 697 taskqueue_member(struct taskqueue *queue, struct thread *td)
 698 {
 699         int i, j, ret = 0;
 700
 701         for (i = 0, j = 0; ; i++) {
 702                 if (queue->tq_threads[i] == NULL)
 703                         continue;
 704                 if (queue->tq_threads[i] == td) {
 705                         ret = 1;
 706                         break;
 707                 }
 708                 if (++j >= queue->tq_tcount)
 709                         break;
 710         }
 711         return (ret);
 712 }