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/* $OpenBSD: kern_workq.c,v 1.14 2013/11/26 20:33:19 deraadt Exp $ */
/*
* Copyright (c) 2007 David Gwynne <dlg@openbsd.org>
* Copyright (c) 2007 Ted Unangst <tedu@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/queue.h>
#include <sys/mutex.h>
#include <sys/kthread.h>
#include <sys/workq.h>
struct workq {
enum {
WQ_S_CREATED,
WQ_S_RUNNING,
WQ_S_DESTROYED
} wq_state;
int wq_running;
int wq_max;
const char *wq_name;
struct mutex wq_mtx;
SIMPLEQ_HEAD(, workq_task) wq_tasklist;
};
struct pool workq_task_pool;
struct workq workq_syswq = {
WQ_S_CREATED,
0,
1,
"syswq"
};
/* if we allocate the wqt, we need to know we free it too */
#define WQT_F_POOL (1U << 31)
void workq_init(void); /* called in init_main.c */
void workq_create_thread(void *);
struct workq_task * workq_next_task(struct workq *);
void workq_thread(void *);
void
workq_init(void)
{
pool_init(&workq_task_pool, sizeof(struct workq_task), 0, 0,
0, "wqtasks", NULL);
pool_setipl(&workq_task_pool, IPL_HIGH);
mtx_init(&workq_syswq.wq_mtx, IPL_HIGH);
SIMPLEQ_INIT(&workq_syswq.wq_tasklist);
kthread_create_deferred(workq_create_thread, &workq_syswq);
}
struct workq *
workq_create(const char *name, int maxqs, int ipl)
{
struct workq *wq;
wq = malloc(sizeof(*wq), M_DEVBUF, M_NOWAIT);
if (wq == NULL)
return (NULL);
wq->wq_state = WQ_S_CREATED;
wq->wq_running = 0;
wq->wq_max = maxqs;
wq->wq_name = name;
mtx_init(&wq->wq_mtx, ipl);
SIMPLEQ_INIT(&wq->wq_tasklist);
/* try to create a thread to guarantee that tasks will be serviced */
kthread_create_deferred(workq_create_thread, wq);
return (wq);
}
void
workq_destroy(struct workq *wq)
{
mtx_enter(&wq->wq_mtx);
switch (wq->wq_state) {
case WQ_S_CREATED:
/* wq is still referenced by workq_create_thread */
wq->wq_state = WQ_S_DESTROYED;
mtx_leave(&wq->wq_mtx);
return;
case WQ_S_RUNNING:
wq->wq_state = WQ_S_DESTROYED;
break;
default:
panic("unexpected %s wq state %d", wq->wq_name, wq->wq_state);
}
while (wq->wq_running != 0) {
wakeup(wq);
msleep(&wq->wq_running, &wq->wq_mtx, PWAIT, "wqdestroy", 0);
}
mtx_leave(&wq->wq_mtx);
free(wq, M_DEVBUF);
}
int
workq_add_task(struct workq *wq, int flags, workq_fn func, void *a1, void *a2)
{
struct workq_task *wqt;
wqt = pool_get(&workq_task_pool, (flags & WQ_WAITOK) ?
PR_WAITOK : PR_NOWAIT);
if (!wqt)
return (ENOMEM);
workq_queue_task(wq, wqt, WQT_F_POOL | flags, func, a1, a2);
return (0);
}
void
workq_queue_task(struct workq *wq, struct workq_task *wqt, int flags,
workq_fn func, void *a1, void *a2)
{
wqt->wqt_flags = flags;
wqt->wqt_func = func;
wqt->wqt_arg1 = a1;
wqt->wqt_arg2 = a2;
if (wq == NULL)
wq = &workq_syswq;
mtx_enter(&wq->wq_mtx);
SIMPLEQ_INSERT_TAIL(&wq->wq_tasklist, wqt, wqt_entry);
mtx_leave(&wq->wq_mtx);
wakeup_one(wq);
}
void
workq_create_thread(void *arg)
{
struct workq *wq = arg;
int rv;
mtx_enter(&wq->wq_mtx);
switch (wq->wq_state) {
case WQ_S_DESTROYED:
mtx_leave(&wq->wq_mtx);
free(wq, M_DEVBUF);
return;
case WQ_S_CREATED:
wq->wq_state = WQ_S_RUNNING;
break;
default:
panic("unexpected %s wq state %d", wq->wq_name, wq->wq_state);
}
do {
wq->wq_running++;
mtx_leave(&wq->wq_mtx);
rv = kthread_create(workq_thread, wq, NULL, wq->wq_name);
mtx_enter(&wq->wq_mtx);
if (rv != 0) {
printf("unable to create workq thread for \"%s\"\n",
wq->wq_name);
wq->wq_running--;
/* could have been destroyed during kthread_create */
if (wq->wq_state == WQ_S_DESTROYED &&
wq->wq_running == 0)
wakeup_one(&wq->wq_running);
break;
}
} while (wq->wq_running < wq->wq_max);
mtx_leave(&wq->wq_mtx);
}
struct workq_task *
workq_next_task(struct workq *wq)
{
struct workq_task *wqt;
mtx_enter(&wq->wq_mtx);
for (;;) {
wqt = SIMPLEQ_FIRST(&wq->wq_tasklist);
if (wqt != NULL) {
SIMPLEQ_REMOVE_HEAD(&wq->wq_tasklist, wqt_entry);
break;
} else if (wq->wq_state == WQ_S_RUNNING)
msleep(wq, &wq->wq_mtx, PWAIT, "bored", 0);
else {
if (--wq->wq_running == 0)
wakeup_one(&wq->wq_running);
break;
}
}
mtx_leave(&wq->wq_mtx);
return (wqt);
}
void
workq_thread(void *arg)
{
struct workq *wq = arg;
struct workq_task *wqt;
int mypool;
while ((wqt = workq_next_task(wq)) != NULL) {
mypool = (wqt->wqt_flags & WQT_F_POOL);
wqt->wqt_func(wqt->wqt_arg1, wqt->wqt_arg2);
if (mypool)
pool_put(&workq_task_pool, wqt);
}
kthread_exit(0);
}
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