freebsd-src/sys/sys/taskqueue.h
Scott Long 7874f606d5 Introduce a new taskqueue that runs completely free of Giant, and in
turns runs its tasks free of Giant too.  It is intended that as drivers
become locked down, they will move out of the old, Giant-bound taskqueue
and into this new one.  The old taskqueue has been renamed to
taskqueue_swi_giant, and the new one keeps the name taskqueue_swi.
2003-02-26 03:15:42 +00:00

117 lines
3.8 KiB
C

/*-
* 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.
*
* $FreeBSD$
*/
#ifndef _SYS_TASKQUEUE_H_
#define _SYS_TASKQUEUE_H_
#ifndef _KERNEL
#error "no user-servicable parts inside"
#endif
#include <sys/queue.h>
struct taskqueue;
/*
* Each task includes a function which is called from
* taskqueue_run(). The first argument is taken from the 'ta_context'
* field of struct task and the second argument is a count of how many
* times the task was enqueued before the call to taskqueue_run().
*/
typedef void task_fn_t(void *context, int pending);
/*
* A notification callback function which is called from
* taskqueue_enqueue(). The context argument is given in the call to
* taskqueue_create(). This function would normally be used to allow the
* queue to arrange to run itself later (e.g., by scheduling a software
* interrupt or waking a kernel thread).
*/
typedef void (*taskqueue_enqueue_fn)(void *context);
struct task {
STAILQ_ENTRY(task) ta_link; /* link for queue */
int ta_pending; /* count times queued */
int ta_priority; /* priority of task in queue */
task_fn_t *ta_func; /* task handler */
void *ta_context; /* argument for handler */
};
struct taskqueue *taskqueue_create(const char *name, int mflags,
taskqueue_enqueue_fn enqueue,
void *context);
int taskqueue_enqueue(struct taskqueue *queue, struct task *task);
struct taskqueue *taskqueue_find(const char *name);
void taskqueue_free(struct taskqueue *queue);
void taskqueue_run(struct taskqueue *queue);
/*
* Initialise a task structure.
*/
#define TASK_INIT(task, priority, func, context) do { \
(task)->ta_pending = 0; \
(task)->ta_priority = (priority); \
(task)->ta_func = (func); \
(task)->ta_context = (context); \
} while (0)
/*
* Declare a reference to a taskqueue.
*/
#define TASKQUEUE_DECLARE(name) \
extern struct taskqueue *taskqueue_##name
/*
* Define and initialise a taskqueue.
*/
#define TASKQUEUE_DEFINE(name, enqueue, context, init) \
\
struct taskqueue *taskqueue_##name; \
\
static void \
taskqueue_define_##name(void *arg) \
{ \
taskqueue_##name = \
taskqueue_create(#name, M_NOWAIT, (enqueue), (context)); \
init; \
} \
\
SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND, \
taskqueue_define_##name, NULL) \
\
struct __hack
/*
* This queue is serviced by a software interrupt handler. To enqueue
* a task, call taskqueue_enqueue(taskqueue_swi, &task).
*/
TASKQUEUE_DECLARE(swi_giant);
TASKQUEUE_DECLARE(swi);
#endif /* !_SYS_TASKQUEUE_H_ */