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: src/sys/sys/taskqueue.h,v 1.3.2.2 2003/09/10 00:40:39 ken Exp $
  27  * $DragonFly: src/sys/sys/taskqueue.h,v 1.6 2005/09/21 18:58:55 hsu Exp $
  28  */
  29
  30 #ifndef _SYS_TASKQUEUE_H_
  31 #define _SYS_TASKQUEUE_H_
  32
  33 #if !defined(_KERNEL)
  34 #error "This file should not be included by userland programs."
  35 #endif
  36
  37 #include <sys/queue.h>
  38
  39 struct taskqueue;
  40
  41 /*
  42  * Each task includes a function which is called from
  43  * taskqueue_run().  The first argument is taken from the 'ta_context'
  44  * field of struct task and the second argument is a count of how many
  45  * times the task was enqueued before the call to taskqueue_run().
  46  */
  47 typedef void task_fn_t(void *context, int pending);
  48
  49 /*
  50  * A notification callback function which is called from
  51  * taskqueue_enqueue().  The context argument is given in the call to
  52  * taskqueue_create().  This function would normally be used to allow the
  53  * queue to arrange to run itself later (e.g., by scheduling a software
  54  * interrupt or waking a kernel thread).
  55  */
  56 typedef void (*taskqueue_enqueue_fn)(void *context);
  57
  58 struct task {
  59         STAILQ_ENTRY(task) ta_link;     /* link for queue */
  60         int     ta_pending;             /* count times queued */
  61         int     ta_priority;            /* priority of task in queue */
  62         task_fn_t *ta_func;             /* task handler */
  63         void    *ta_context;            /* argument for handler */
  64 };
  65
  66 struct taskqueue *taskqueue_create(const char *name, int mflags,
  67                                     taskqueue_enqueue_fn enqueue,
  68                                     void *context);
  69 int     taskqueue_enqueue(struct taskqueue *queue, struct task *task);
  70 struct taskqueue *taskqueue_find(const char *name);
  71 void    taskqueue_free(struct taskqueue *queue);
  72 void    taskqueue_run(struct taskqueue *queue);
  73
  74 /*
  75  * Initialise a task structure.
  76  */
  77 #define TASK_INIT(task, priority, func, context) do {   \
  78         (task)->ta_pending = 0;                         \
  79         (task)->ta_priority = (priority);               \
  80         (task)->ta_func = (func);                       \
  81         (task)->ta_context = (context);                 \
  82 } while (0)
  83
  84 /*
  85  * Declare a reference to a taskqueue.
  86  */
  87 #define TASKQUEUE_DECLARE(name)                 \
  88 extern struct taskqueue *taskqueue_##name
  89
  90 /*
  91  * Define and initialise a taskqueue.
  92  */
  93 #define TASKQUEUE_DEFINE(name, enqueue, context, init)                  \
  94                                                                         \
  95 struct taskqueue *taskqueue_##name;                                     \
  96                                                                         \
  97 static void                                                             \
  98 taskqueue_define_##name(void *arg)                                      \
  99 {                                                                       \
 100         taskqueue_##name =                                              \
 101             taskqueue_create(#name, M_INTWAIT, (enqueue), (context));   \
 102         init;                                                           \
 103 }                                                                       \
 104                                                                         \
 105 SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND,            \
 106         taskqueue_define_##name, NULL)                                  \
 107                                                                         \
 108 struct __hack
 109
 110 /*
 111  * This queue is serviced by a software interrupt handler.  To enqueue
 112  * a task, call taskqueue_enqueue(taskqueue_swi, &task).
 113  */
 114 TASKQUEUE_DECLARE(swi);
 115
 116 /*
 117  * This queue is serviced by a per-cpu kernel thread.  To enqueue a task, call
 118  * taskqueue_enqueue(taskqueue_thread[mycpuid], &task).
 119  */
 120 extern struct taskqueue *taskqueue_thread[];
 121
 122 #endif /* !_SYS_TASKQUEUE_H_ */