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 /*
 394  * Only use this function in single threaded contexts. It returns
 395  * non-zero if the given task is either pending or running. Else the
 396  * task is idle and can be queued again or freed.
 397  */
 398 int
 399 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
 400 {
 401         int retval;
 402
 403         TQ_LOCK(queue);
 404         retval = task->ta_pending > 0 || task_is_running(queue, task);
 405         TQ_UNLOCK(queue);
 406
 407         return (retval);
 408 }
 409
 410 static int
 411 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 412     u_int *pendp)
 413 {
 414
 415         if (task->ta_pending > 0)
 416                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 417         if (pendp != NULL)
 418                 *pendp = task->ta_pending;
 419         task->ta_pending = 0;
 420         return (task_is_running(queue, task) ? EBUSY : 0);
 421 }
 422
 423 int
 424 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 425 {
 426         int error;
 427
 428         TQ_LOCK(queue);
 429         error = taskqueue_cancel_locked(queue, task, pendp);
 430         TQ_UNLOCK(queue);
 431
 432         return (error);
 433 }
 434
 435 int
 436 taskqueue_cancel_timeout(struct taskqueue *queue,
 437     struct timeout_task *timeout_task, u_int *pendp)
 438 {
 439         u_int pending, pending1;
 440         int error;
 441
 442         TQ_LOCK(queue);
 443         pending = !!callout_stop(&timeout_task->c);
 444         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 445         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 446                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 447                 queue->tq_callouts--;
 448         }
 449         TQ_UNLOCK(queue);
 450
 451         if (pendp != NULL)
 452                 *pendp = pending + pending1;
 453         return (error);
 454 }
 455
 456 void
 457 taskqueue_drain(struct taskqueue *queue, struct task *task)
 458 {
 459
 460         if (!queue->tq_spin)
 461                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 462
 463         TQ_LOCK(queue);
 464         while (task->ta_pending != 0 || task_is_running(queue, task))
 465                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 466         TQ_UNLOCK(queue);
 467 }
 468
 469 void
 470 taskqueue_drain_all(struct taskqueue *queue)
 471 {
 472         struct task *task;
 473
 474         if (!queue->tq_spin)
 475                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 476
 477         TQ_LOCK(queue);
 478         task = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 479         while (task != NULL && task->ta_pending != 0) {
 480                 struct task *oldtask;
 481                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 482                 /*
 483                  * While we were asleeep the last entry may have been freed.
 484                  * We need to check if it's still even in the queue.
 485                  * Not perfect, but it's better than referencing bad memory.
 486                  * first guess is the current 'end of queue' but if a new
 487                  * item has been added we need to take the expensive path
 488                  * Better fix in 11.
 489                  */
 490                 oldtask = task;
 491                 if (oldtask !=
 492                     (task = STAILQ_LAST(&queue->tq_queue, task, ta_link))) {
 493                         STAILQ_FOREACH(task, &queue->tq_queue, ta_link) {
 494                                 if (task == oldtask)
 495                                         break;
 496                         }
 497                 }
 498         }
 499         taskqueue_drain_running(queue);
 500         KASSERT(STAILQ_EMPTY(&queue->tq_queue),
 501             ("taskqueue queue is not empty after draining"));
 502         TQ_UNLOCK(queue);
 503 }
 504
 505 void
 506 taskqueue_drain_timeout(struct taskqueue *queue,
 507     struct timeout_task *timeout_task)
 508 {
 509
 510         /*
 511          * Set flag to prevent timer from re-starting during drain:
 512          */
 513         TQ_LOCK(queue);
 514         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 515             ("Drain already in progress"));
 516         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 517         TQ_UNLOCK(queue);
 518
 519         callout_drain(&timeout_task->c);
 520         taskqueue_drain(queue, &timeout_task->t);
 521
 522         /*
 523          * Clear flag to allow timer to re-start:
 524          */
 525         TQ_LOCK(queue);
 526         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 527         TQ_UNLOCK(queue);
 528 }
 529
 530 static void
 531 taskqueue_swi_enqueue(void *context)
 532 {
 533         swi_sched(taskqueue_ih, 0);
 534 }
 535
 536 static void
 537 taskqueue_swi_run(void *dummy)
 538 {
 539         taskqueue_run(taskqueue_swi);
 540 }
 541
 542 static void
 543 taskqueue_swi_giant_enqueue(void *context)
 544 {
 545         swi_sched(taskqueue_giant_ih, 0);
 546 }
 547
 548 static void
 549 taskqueue_swi_giant_run(void *dummy)
 550 {
 551         taskqueue_run(taskqueue_swi_giant);
 552 }
 553
 554 int
 555 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 556                         const char *name, ...)
 557 {
 558         va_list ap;
 559         struct thread *td;
 560         struct taskqueue *tq;
 561         int i, error;
 562         char ktname[MAXCOMLEN + 1];
 563
 564         if (count <= 0)
 565                 return (EINVAL);
 566
 567         tq = *tqp;
 568
 569         va_start(ap, name);
 570         vsnprintf(ktname, sizeof(ktname), name, ap);
 571         va_end(ap);
 572
 573         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 574             M_NOWAIT | M_ZERO);
 575         if (tq->tq_threads == NULL) {
 576                 printf("%s: no memory for %s threads\n", __func__, ktname);
 577                 return (ENOMEM);
 578         }
 579
 580         for (i = 0; i < count; i++) {
 581                 if (count == 1)
 582                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 583                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 584                 else
 585                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 586                             &tq->tq_threads[i], RFSTOPPED, 0,
 587                             "%s_%d", ktname, i);
 588                 if (error) {
 589                         /* should be ok to continue, taskqueue_free will dtrt */
 590                         printf("%s: kthread_add(%s): error %d", __func__,
 591                             ktname, error);
 592                         tq->tq_threads[i] = NULL;               /* paranoid */
 593                 } else
 594                         tq->tq_tcount++;
 595         }
 596         for (i = 0; i < count; i++) {
 597                 if (tq->tq_threads[i] == NULL)
 598                         continue;
 599                 td = tq->tq_threads[i];
 600                 thread_lock(td);
 601                 sched_prio(td, pri);
 602                 sched_add(td, SRQ_BORING);
 603                 thread_unlock(td);
 604         }
 605
 606         return (0);
 607 }
 608
 609 static inline void
 610 taskqueue_run_callback(struct taskqueue *tq,
 611     enum taskqueue_callback_type cb_type)
 612 {
 613         taskqueue_callback_fn tq_callback;
 614
 615         TQ_ASSERT_UNLOCKED(tq);
 616         tq_callback = tq->tq_callbacks[cb_type];
 617         if (tq_callback != NULL)
 618                 tq_callback(tq->tq_cb_contexts[cb_type]);
 619 }
 620
 621 void
 622 taskqueue_thread_loop(void *arg)
 623 {
 624         struct taskqueue **tqp, *tq;
 625
 626         tqp = arg;
 627         tq = *tqp;
 628         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 629         TQ_LOCK(tq);
 630         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 631                 taskqueue_run_locked(tq);
 632                 /*
 633                  * Because taskqueue_run() can drop tq_mutex, we need to
 634                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 635                  * meantime, which means we missed a wakeup.
 636                  */
 637                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 638                         break;
 639                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 640         }
 641         taskqueue_run_locked(tq);
 642
 643         /*
 644          * This thread is on its way out, so just drop the lock temporarily
 645          * in order to call the shutdown callback.  This allows the callback
 646          * to look at the taskqueue, even just before it dies.
 647          */
 648         TQ_UNLOCK(tq);
 649         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 650         TQ_LOCK(tq);
 651
 652         /* rendezvous with thread that asked us to terminate */
 653         tq->tq_tcount--;
 654         wakeup_one(tq->tq_threads);
 655         TQ_UNLOCK(tq);
 656         kthread_exit();
 657 }
 658
 659 void
 660 taskqueue_thread_enqueue(void *context)
 661 {
 662         struct taskqueue **tqp, *tq;
 663
 664         tqp = context;
 665         tq = *tqp;
 666
 667         wakeup_one(tq);
 668 }
 669
 670 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 671                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 672                      INTR_MPSAFE, &taskqueue_ih));
 673
 674 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 675                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 676                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 677
 678 TASKQUEUE_DEFINE_THREAD(thread);
 679
 680 struct taskqueue *
 681 taskqueue_create_fast(const char *name, int mflags,
 682                  taskqueue_enqueue_fn enqueue, void *context)
 683 {
 684         return _taskqueue_create(name, mflags, enqueue, context,
 685                         MTX_SPIN, "fast_taskqueue");
 686 }
 687
 688 /* NB: for backwards compatibility */
 689 int
 690 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
 691 {
 692         return taskqueue_enqueue(queue, task);
 693 }
 694
 695 static void     *taskqueue_fast_ih;
 696
 697 static void
 698 taskqueue_fast_enqueue(void *context)
 699 {
 700         swi_sched(taskqueue_fast_ih, 0);
 701 }
 702
 703 static void
 704 taskqueue_fast_run(void *dummy)
 705 {
 706         taskqueue_run(taskqueue_fast);
 707 }
 708
 709 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 710         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 711         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 712
 713 int
 714 taskqueue_member(struct taskqueue *queue, struct thread *td)
 715 {
 716         int i, j, ret = 0;
 717
 718         for (i = 0, j = 0; ; i++) {
 719                 if (queue->tq_threads[i] == NULL)
 720                         continue;
 721                 if (queue->tq_threads[i] == td) {
 722                         ret = 1;
 723                         break;
 724                 }
 725                 if (++j >= queue->tq_tcount)
 726                         break;
 727         }
 728         return (ret);
 729 }