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/*-
* Copyright (c) 2000 Doug Rabson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/taskqueue.h>
static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
static void *taskqueue_ih;
static struct mtx taskqueue_queues_mutex;
struct taskqueue {
STAILQ_ENTRY(taskqueue) tq_link;
STAILQ_HEAD(, task) tq_queue;
const char *tq_name;
taskqueue_enqueue_fn tq_enqueue;
void *tq_context;
int tq_draining;
struct mtx tq_mutex;
};
static void init_taskqueue_list(void *data);
static void
init_taskqueue_list(void *data __unused)
{
mtx_init(&taskqueue_queues_mutex, "taskqueue list", MTX_DEF);
STAILQ_INIT(&taskqueue_queues);
}
SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
NULL);
struct taskqueue *
taskqueue_create(const char *name, int mflags,
taskqueue_enqueue_fn enqueue, void *context)
{
struct taskqueue *queue;
queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
if (!queue)
return 0;
STAILQ_INIT(&queue->tq_queue);
queue->tq_name = name;
queue->tq_enqueue = enqueue;
queue->tq_context = context;
queue->tq_draining = 0;
mtx_init(&queue->tq_mutex, "taskqueue", MTX_DEF);
mtx_lock(&taskqueue_queues_mutex);
STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
mtx_unlock(&taskqueue_queues_mutex);
return queue;
}
void
taskqueue_free(struct taskqueue *queue)
{
mtx_lock(&queue->tq_mutex);
queue->tq_draining = 1;
mtx_unlock(&queue->tq_mutex);
taskqueue_run(queue);
mtx_lock(&taskqueue_queues_mutex);
STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
mtx_unlock(&taskqueue_queues_mutex);
mtx_destroy(&queue->tq_mutex);
free(queue, M_TASKQUEUE);
}
/*
* Returns with the taskqueue locked.
*/
struct taskqueue *
taskqueue_find(const char *name)
{
struct taskqueue *queue;
mtx_lock(&taskqueue_queues_mutex);
STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
mtx_lock(&queue->tq_mutex);
if (!strcmp(queue->tq_name, name)) {
mtx_unlock(&taskqueue_queues_mutex);
return queue;
}
mtx_unlock(&queue->tq_mutex);
}
mtx_unlock(&taskqueue_queues_mutex);
return 0;
}
int
taskqueue_enqueue(struct taskqueue *queue, struct task *task)
{
struct task *ins;
struct task *prev;
mtx_lock(&queue->tq_mutex);
/*
* Don't allow new tasks on a queue which is being freed.
*/
if (queue->tq_draining) {
mtx_unlock(&queue->tq_mutex);
return EPIPE;
}
/*
* Count multiple enqueues.
*/
if (task->ta_pending) {
task->ta_pending++;
mtx_unlock(&queue->tq_mutex);
return 0;
}
/*
* Optimise the case when all tasks have the same priority.
*/
prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
if (!prev || prev->ta_priority >= task->ta_priority) {
STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
} else {
prev = 0;
for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
prev = ins, ins = STAILQ_NEXT(ins, ta_link))
if (ins->ta_priority < task->ta_priority)
break;
if (prev)
STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
else
STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
}
task->ta_pending = 1;
if (queue->tq_enqueue)
queue->tq_enqueue(queue->tq_context);
mtx_unlock(&queue->tq_mutex);
return 0;
}
void
taskqueue_run(struct taskqueue *queue)
{
struct task *task;
int pending;
mtx_lock(&queue->tq_mutex);
while (STAILQ_FIRST(&queue->tq_queue)) {
/*
* Carefully remove the first task from the queue and
* zero its pending count.
*/
task = STAILQ_FIRST(&queue->tq_queue);
STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
pending = task->ta_pending;
task->ta_pending = 0;
mtx_unlock(&queue->tq_mutex);
task->ta_func(task->ta_context, pending);
mtx_lock(&queue->tq_mutex);
}
mtx_unlock(&queue->tq_mutex);
}
static void
taskqueue_swi_enqueue(void *context)
{
swi_sched(taskqueue_ih, 0);
}
static void
taskqueue_swi_run(void *dummy)
{
taskqueue_run(taskqueue_swi);
}
TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 0,
&taskqueue_ih));
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