FreeBSD/Linux Kernel Cross Reference
sys/sys/taskqueue.h
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 * $FreeBSD: releng/5.1/sys/sys/taskqueue.h 111528 2003-02-26 03:15:42Z scottl $
27 */
28
29 #ifndef _SYS_TASKQUEUE_H_
30 #define _SYS_TASKQUEUE_H_
31
32 #ifndef _KERNEL
33 #error "no user-servicable parts inside"
34 #endif
35
36 #include <sys/queue.h>
37
38 struct taskqueue;
39
40 /*
41 * Each task includes a function which is called from
42 * taskqueue_run(). The first argument is taken from the 'ta_context'
43 * field of struct task and the second argument is a count of how many
44 * times the task was enqueued before the call to taskqueue_run().
45 */
46 typedef void task_fn_t(void *context, int pending);
47
48 /*
49 * A notification callback function which is called from
50 * taskqueue_enqueue(). The context argument is given in the call to
51 * taskqueue_create(). This function would normally be used to allow the
52 * queue to arrange to run itself later (e.g., by scheduling a software
53 * interrupt or waking a kernel thread).
54 */
55 typedef void (*taskqueue_enqueue_fn)(void *context);
56
57 struct task {
58 STAILQ_ENTRY(task) ta_link; /* link for queue */
59 int ta_pending; /* count times queued */
60 int ta_priority; /* priority of task in queue */
61 task_fn_t *ta_func; /* task handler */
62 void *ta_context; /* argument for handler */
63 };
64
65 struct taskqueue *taskqueue_create(const char *name, int mflags,
66 taskqueue_enqueue_fn enqueue,
67 void *context);
68 int taskqueue_enqueue(struct taskqueue *queue, struct task *task);
69 struct taskqueue *taskqueue_find(const char *name);
70 void taskqueue_free(struct taskqueue *queue);
71 void taskqueue_run(struct taskqueue *queue);
72
73 /*
74 * Initialise a task structure.
75 */
76 #define TASK_INIT(task, priority, func, context) do { \
77 (task)->ta_pending = 0; \
78 (task)->ta_priority = (priority); \
79 (task)->ta_func = (func); \
80 (task)->ta_context = (context); \
81 } while (0)
82
83 /*
84 * Declare a reference to a taskqueue.
85 */
86 #define TASKQUEUE_DECLARE(name) \
87 extern struct taskqueue *taskqueue_##name
88
89 /*
90 * Define and initialise a taskqueue.
91 */
92 #define TASKQUEUE_DEFINE(name, enqueue, context, init) \
93 \
94 struct taskqueue *taskqueue_##name; \
95 \
96 static void \
97 taskqueue_define_##name(void *arg) \
98 { \
99 taskqueue_##name = \
100 taskqueue_create(#name, M_NOWAIT, (enqueue), (context)); \
101 init; \
102 } \
103 \
104 SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND, \
105 taskqueue_define_##name, NULL) \
106 \
107 struct __hack
108
109 /*
110 * This queue is serviced by a software interrupt handler. To enqueue
111 * a task, call taskqueue_enqueue(taskqueue_swi, &task).
112 */
113 TASKQUEUE_DECLARE(swi_giant);
114 TASKQUEUE_DECLARE(swi);
115
116 #endif /* !_SYS_TASKQUEUE_H_ */
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