2 * Copyright (c) 2017 Hans Petter Selasky
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <linux/workqueue.h>
31 #include <linux/wait.h>
32 #include <linux/compat.h>
33 #include <linux/spinlock.h>
35 #include <sys/kernel.h>
38 * Define all work struct states
41 WORK_ST_IDLE, /* idle - not started */
42 WORK_ST_TIMER, /* timer is being started */
43 WORK_ST_TASK, /* taskqueue is being queued */
44 WORK_ST_EXEC, /* callback is being called */
45 WORK_ST_CANCEL, /* cancel is being requested */
50 * Define global workqueues
52 static struct workqueue_struct *linux_system_short_wq;
53 static struct workqueue_struct *linux_system_long_wq;
55 struct workqueue_struct *system_wq;
56 struct workqueue_struct *system_long_wq;
57 struct workqueue_struct *system_unbound_wq;
58 struct workqueue_struct *system_highpri_wq;
59 struct workqueue_struct *system_power_efficient_wq;
61 static int linux_default_wq_cpus = 4;
63 static void linux_delayed_work_timer_fn(void *);
66 * This function atomically updates the work state and returns the
67 * previous state at the time of update.
70 linux_update_state(atomic_t *v, const uint8_t *pstate)
76 while ((old = atomic_cmpxchg(v, c, pstate[c])) != c)
83 * A LinuxKPI task is allowed to free itself inside the callback function
84 * and cannot safely be referred after the callback function has
85 * completed. This function gives the linux_work_fn() function a hint,
86 * that the task is not going away and can have its state checked
87 * again. Without this extra hint LinuxKPI tasks cannot be serialized
88 * accross multiple worker threads.
91 linux_work_exec_unblock(struct work_struct *work)
93 struct workqueue_struct *wq;
94 struct work_exec *exec;
97 wq = work->work_queue;
98 if (unlikely(wq == NULL))
102 TAILQ_FOREACH(exec, &wq->exec_head, entry) {
103 if (exec->target == work) {
115 linux_delayed_work_enqueue(struct delayed_work *dwork)
117 struct taskqueue *tq;
119 tq = dwork->work.work_queue->taskqueue;
120 taskqueue_enqueue(tq, &dwork->work.work_task);
124 * This function queues the given work structure on the given
125 * workqueue. It returns non-zero if the work was successfully
126 * [re-]queued. Else the work is already pending for completion.
129 linux_queue_work_on(int cpu __unused, struct workqueue_struct *wq,
130 struct work_struct *work)
132 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
133 [WORK_ST_IDLE] = WORK_ST_TASK, /* start queuing task */
134 [WORK_ST_TIMER] = WORK_ST_TIMER, /* NOP */
135 [WORK_ST_TASK] = WORK_ST_TASK, /* NOP */
136 [WORK_ST_EXEC] = WORK_ST_TASK, /* queue task another time */
137 [WORK_ST_CANCEL] = WORK_ST_TASK, /* start queuing task again */
140 if (atomic_read(&wq->draining) != 0)
141 return (!work_pending(work));
143 switch (linux_update_state(&work->state, states)) {
146 if (linux_work_exec_unblock(work) != 0)
150 work->work_queue = wq;
151 taskqueue_enqueue(wq->taskqueue, &work->work_task);
154 return (0); /* already on a queue */
159 * This function queues the given work structure on the given
160 * workqueue after a given delay in ticks. It returns non-zero if the
161 * work was successfully [re-]queued. Else the work is already pending
165 linux_queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
166 struct delayed_work *dwork, unsigned delay)
168 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
169 [WORK_ST_IDLE] = WORK_ST_TIMER, /* start timeout */
170 [WORK_ST_TIMER] = WORK_ST_TIMER, /* NOP */
171 [WORK_ST_TASK] = WORK_ST_TASK, /* NOP */
172 [WORK_ST_EXEC] = WORK_ST_TIMER, /* start timeout */
173 [WORK_ST_CANCEL] = WORK_ST_TIMER, /* start timeout */
176 if (atomic_read(&wq->draining) != 0)
177 return (!work_pending(&dwork->work));
179 switch (linux_update_state(&dwork->work.state, states)) {
182 if (delay == 0 && linux_work_exec_unblock(&dwork->work) != 0) {
183 dwork->timer.expires = jiffies;
188 dwork->work.work_queue = wq;
189 dwork->timer.expires = jiffies + delay;
192 linux_delayed_work_enqueue(dwork);
193 } else if (unlikely(cpu != WORK_CPU_UNBOUND)) {
194 mtx_lock(&dwork->timer.mtx);
195 callout_reset_on(&dwork->timer.callout, delay,
196 &linux_delayed_work_timer_fn, dwork, cpu);
197 mtx_unlock(&dwork->timer.mtx);
199 mtx_lock(&dwork->timer.mtx);
200 callout_reset(&dwork->timer.callout, delay,
201 &linux_delayed_work_timer_fn, dwork);
202 mtx_unlock(&dwork->timer.mtx);
206 return (0); /* already on a queue */
211 linux_work_fn(void *context, int pending)
213 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
214 [WORK_ST_IDLE] = WORK_ST_IDLE, /* NOP */
215 [WORK_ST_TIMER] = WORK_ST_EXEC, /* delayed work w/o timeout */
216 [WORK_ST_TASK] = WORK_ST_EXEC, /* call callback */
217 [WORK_ST_EXEC] = WORK_ST_IDLE, /* complete callback */
218 [WORK_ST_CANCEL] = WORK_ST_EXEC, /* failed to cancel */
220 struct work_struct *work;
221 struct workqueue_struct *wq;
222 struct work_exec exec;
223 struct task_struct *task;
227 /* setup local variables */
229 wq = work->work_queue;
231 /* store target pointer */
234 /* insert executor into list */
236 TAILQ_INSERT_TAIL(&wq->exec_head, &exec, entry);
238 switch (linux_update_state(&work->state, states)) {
244 /* set current work structure */
247 /* call work function */
250 /* set current work structure */
254 /* check if unblocked */
255 if (exec.target != work) {
266 /* remove executor from list */
267 TAILQ_REMOVE(&wq->exec_head, &exec, entry);
272 linux_delayed_work_fn(void *context, int pending)
274 struct delayed_work *dwork = context;
277 * Make sure the timer belonging to the delayed work gets
278 * drained before invoking the work function. Else the timer
279 * mutex may still be in use which can lead to use-after-free
280 * situations, because the work function might free the work
281 * structure before returning.
283 callout_drain(&dwork->timer.callout);
285 linux_work_fn(&dwork->work, pending);
289 linux_delayed_work_timer_fn(void *arg)
291 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
292 [WORK_ST_IDLE] = WORK_ST_IDLE, /* NOP */
293 [WORK_ST_TIMER] = WORK_ST_TASK, /* start queueing task */
294 [WORK_ST_TASK] = WORK_ST_TASK, /* NOP */
295 [WORK_ST_EXEC] = WORK_ST_EXEC, /* NOP */
296 [WORK_ST_CANCEL] = WORK_ST_TASK, /* failed to cancel */
298 struct delayed_work *dwork = arg;
300 switch (linux_update_state(&dwork->work.state, states)) {
303 linux_delayed_work_enqueue(dwork);
311 * This function cancels the given work structure in a synchronous
312 * fashion. It returns non-zero if the work was successfully
313 * cancelled. Else the work was already cancelled.
316 linux_cancel_work_sync(struct work_struct *work)
318 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
319 [WORK_ST_IDLE] = WORK_ST_IDLE, /* NOP */
320 [WORK_ST_TIMER] = WORK_ST_TIMER, /* can't happen */
321 [WORK_ST_TASK] = WORK_ST_IDLE, /* cancel and drain */
322 [WORK_ST_EXEC] = WORK_ST_IDLE, /* too late, drain */
323 [WORK_ST_CANCEL] = WORK_ST_IDLE, /* cancel and drain */
325 struct taskqueue *tq;
327 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
328 "linux_cancel_work_sync() might sleep");
330 switch (linux_update_state(&work->state, states)) {
335 tq = work->work_queue->taskqueue;
336 if (taskqueue_cancel(tq, &work->work_task, NULL) != 0)
337 taskqueue_drain(tq, &work->work_task);
340 tq = work->work_queue->taskqueue;
341 if (taskqueue_cancel(tq, &work->work_task, NULL) != 0)
342 taskqueue_drain(tq, &work->work_task);
348 * This function atomically stops the timer and callback. The timer
349 * callback will not be called after this function returns. This
350 * functions returns true when the timeout was cancelled. Else the
351 * timeout was not started or has already been called.
354 linux_cancel_timer(struct delayed_work *dwork, bool drain)
358 mtx_lock(&dwork->timer.mtx);
359 cancelled = (callout_stop(&dwork->timer.callout) == 1);
360 mtx_unlock(&dwork->timer.mtx);
362 /* check if we should drain */
364 callout_drain(&dwork->timer.callout);
369 * This function cancels the given delayed work structure in a
370 * non-blocking fashion. It returns non-zero if the work was
371 * successfully cancelled. Else the work may still be busy or already
375 linux_cancel_delayed_work(struct delayed_work *dwork)
377 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
378 [WORK_ST_IDLE] = WORK_ST_IDLE, /* NOP */
379 [WORK_ST_TIMER] = WORK_ST_CANCEL, /* try to cancel */
380 [WORK_ST_TASK] = WORK_ST_CANCEL, /* try to cancel */
381 [WORK_ST_EXEC] = WORK_ST_EXEC, /* NOP */
382 [WORK_ST_CANCEL] = WORK_ST_CANCEL, /* NOP */
384 struct taskqueue *tq;
386 switch (linux_update_state(&dwork->work.state, states)) {
389 if (linux_cancel_timer(dwork, 0)) {
390 atomic_cmpxchg(&dwork->work.state,
391 WORK_ST_CANCEL, WORK_ST_IDLE);
396 tq = dwork->work.work_queue->taskqueue;
397 if (taskqueue_cancel(tq, &dwork->work.work_task, NULL) == 0) {
398 atomic_cmpxchg(&dwork->work.state,
399 WORK_ST_CANCEL, WORK_ST_IDLE);
409 * This function cancels the given work structure in a synchronous
410 * fashion. It returns non-zero if the work was successfully
411 * cancelled. Else the work was already cancelled.
414 linux_cancel_delayed_work_sync(struct delayed_work *dwork)
416 static const uint8_t states[WORK_ST_MAX] __aligned(8) = {
417 [WORK_ST_IDLE] = WORK_ST_IDLE, /* NOP */
418 [WORK_ST_TIMER] = WORK_ST_IDLE, /* cancel and drain */
419 [WORK_ST_TASK] = WORK_ST_IDLE, /* cancel and drain */
420 [WORK_ST_EXEC] = WORK_ST_IDLE, /* too late, drain */
421 [WORK_ST_CANCEL] = WORK_ST_IDLE, /* cancel and drain */
423 struct taskqueue *tq;
425 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
426 "linux_cancel_delayed_work_sync() might sleep");
428 switch (linux_update_state(&dwork->work.state, states)) {
432 tq = dwork->work.work_queue->taskqueue;
433 if (taskqueue_cancel(tq, &dwork->work.work_task, NULL) != 0)
434 taskqueue_drain(tq, &dwork->work.work_task);
438 if (linux_cancel_timer(dwork, 1)) {
440 * Make sure taskqueue is also drained before
443 tq = dwork->work.work_queue->taskqueue;
444 taskqueue_drain(tq, &dwork->work.work_task);
449 tq = dwork->work.work_queue->taskqueue;
450 if (taskqueue_cancel(tq, &dwork->work.work_task, NULL) != 0)
451 taskqueue_drain(tq, &dwork->work.work_task);
457 * This function waits until the given work structure is completed.
458 * It returns non-zero if the work was successfully
459 * waited for. Else the work was not waited for.
462 linux_flush_work(struct work_struct *work)
464 struct taskqueue *tq;
467 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
468 "linux_flush_work() might sleep");
470 switch (atomic_read(&work->state)) {
474 tq = work->work_queue->taskqueue;
475 retval = taskqueue_poll_is_busy(tq, &work->work_task);
476 taskqueue_drain(tq, &work->work_task);
482 * This function waits until the given delayed work structure is
483 * completed. It returns non-zero if the work was successfully waited
484 * for. Else the work was not waited for.
487 linux_flush_delayed_work(struct delayed_work *dwork)
489 struct taskqueue *tq;
492 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
493 "linux_flush_delayed_work() might sleep");
495 switch (atomic_read(&dwork->work.state)) {
499 if (linux_cancel_timer(dwork, 1))
500 linux_delayed_work_enqueue(dwork);
503 tq = dwork->work.work_queue->taskqueue;
504 retval = taskqueue_poll_is_busy(tq, &dwork->work.work_task);
505 taskqueue_drain(tq, &dwork->work.work_task);
511 * This function returns true if the given work is pending, and not
515 linux_work_pending(struct work_struct *work)
517 switch (atomic_read(&work->state)) {
528 * This function returns true if the given work is busy.
531 linux_work_busy(struct work_struct *work)
533 struct taskqueue *tq;
535 switch (atomic_read(&work->state)) {
539 tq = work->work_queue->taskqueue;
540 return (taskqueue_poll_is_busy(tq, &work->work_task));
546 struct workqueue_struct *
547 linux_create_workqueue_common(const char *name, int cpus)
549 struct workqueue_struct *wq;
552 * If zero CPUs are specified use the default number of CPUs:
555 cpus = linux_default_wq_cpus;
557 wq = kmalloc(sizeof(*wq), M_WAITOK | M_ZERO);
558 wq->taskqueue = taskqueue_create(name, M_WAITOK,
559 taskqueue_thread_enqueue, &wq->taskqueue);
560 atomic_set(&wq->draining, 0);
561 taskqueue_start_threads(&wq->taskqueue, cpus, PWAIT, "%s", name);
562 TAILQ_INIT(&wq->exec_head);
563 mtx_init(&wq->exec_mtx, "linux_wq_exec", NULL, MTX_DEF);
569 linux_destroy_workqueue(struct workqueue_struct *wq)
571 atomic_inc(&wq->draining);
573 taskqueue_free(wq->taskqueue);
574 mtx_destroy(&wq->exec_mtx);
579 linux_init_delayed_work(struct delayed_work *dwork, work_func_t func)
581 memset(dwork, 0, sizeof(*dwork));
582 dwork->work.func = func;
583 TASK_INIT(&dwork->work.work_task, 0, linux_delayed_work_fn, dwork);
584 mtx_init(&dwork->timer.mtx, spin_lock_name("lkpi-dwork"), NULL,
585 MTX_DEF | MTX_NOWITNESS);
586 callout_init_mtx(&dwork->timer.callout, &dwork->timer.mtx, 0);
590 linux_current_work(void)
592 return (current->work);
596 linux_work_init(void *arg)
598 int max_wq_cpus = mp_ncpus + 1;
600 /* avoid deadlock when there are too few threads */
604 /* set default number of CPUs */
605 linux_default_wq_cpus = max_wq_cpus;
607 linux_system_short_wq = alloc_workqueue("linuxkpi_short_wq", 0, max_wq_cpus);
608 linux_system_long_wq = alloc_workqueue("linuxkpi_long_wq", 0, max_wq_cpus);
610 /* populate the workqueue pointers */
611 system_long_wq = linux_system_long_wq;
612 system_wq = linux_system_short_wq;
613 system_power_efficient_wq = linux_system_short_wq;
614 system_unbound_wq = linux_system_short_wq;
615 system_highpri_wq = linux_system_short_wq;
617 SYSINIT(linux_work_init, SI_SUB_TASKQ, SI_ORDER_THIRD, linux_work_init, NULL);
620 linux_work_uninit(void *arg)
622 destroy_workqueue(linux_system_short_wq);
623 destroy_workqueue(linux_system_long_wq);
625 /* clear workqueue pointers */
626 system_long_wq = NULL;
628 system_power_efficient_wq = NULL;
629 system_unbound_wq = NULL;
630 system_highpri_wq = NULL;
632 SYSUNINIT(linux_work_uninit, SI_SUB_TASKQ, SI_ORDER_THIRD, linux_work_uninit, NULL);