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 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/bus.h> 31 #include <sys/queue.h> 32 #include <sys/systm.h> 33 #include <sys/kernel.h> 34 #include <sys/taskqueue.h> 35 #include <sys/interrupt.h> 36 #include <sys/malloc.h> 37 38 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 39 40 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 41 42 static void *taskqueue_ih; 43 44 struct taskqueue { 45 STAILQ_ENTRY(taskqueue) tq_link; 46 STAILQ_HEAD(, task) tq_queue; 47 const char *tq_name; 48 taskqueue_enqueue_fn tq_enqueue; 49 void *tq_context; 50 int tq_draining; 51 }; 52 53 struct taskqueue * 54 taskqueue_create(const char *name, int mflags, 55 taskqueue_enqueue_fn enqueue, void *context) 56 { 57 struct taskqueue *queue; 58 static int once = 1; 59 int s; 60 61 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags); 62 if (!queue) 63 return 0; 64 STAILQ_INIT(&queue->tq_queue); 65 queue->tq_name = name; 66 queue->tq_enqueue = enqueue; 67 queue->tq_context = context; 68 queue->tq_draining = 0; 69 70 s = splhigh(); 71 if (once) { 72 STAILQ_INIT(&taskqueue_queues); 73 once = 0; 74 } 75 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 76 splx(s); 77 78 return queue; 79 } 80 81 void 82 taskqueue_free(struct taskqueue *queue) 83 { 84 int s = splhigh(); 85 queue->tq_draining = 1; 86 splx(s); 87 88 taskqueue_run(queue); 89 90 s = splhigh(); 91 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 92 splx(s); 93 94 free(queue, M_TASKQUEUE); 95 } 96 97 struct taskqueue * 98 taskqueue_find(const char *name) 99 { 100 struct taskqueue *queue; 101 int s; 102 103 s = splhigh(); 104 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) 105 if (!strcmp(queue->tq_name, name)) { 106 splx(s); 107 return queue; 108 } 109 splx(s); 110 return 0; 111 } 112 113 int 114 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 115 { 116 struct task *ins; 117 struct task *prev; 118 119 int s = splhigh(); 120 121 /* 122 * Don't allow new tasks on a queue which is being freed. 123 */ 124 if (queue->tq_draining) { 125 splx(s); 126 return EPIPE; 127 } 128 129 /* 130 * Count multiple enqueues. 131 */ 132 if (task->ta_pending) { 133 task->ta_pending++; 134 splx(s); 135 return 0; 136 } 137 138 /* 139 * Optimise the case when all tasks have the same priority. 140 */ 141 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 142 if (!prev || prev->ta_priority >= task->ta_priority) { 143 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 144 } else { 145 prev = 0; 146 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 147 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 148 if (ins->ta_priority < task->ta_priority) 149 break; 150 151 if (prev) 152 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 153 else 154 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 155 } 156 157 task->ta_pending = 1; 158 if (queue->tq_enqueue) 159 queue->tq_enqueue(queue->tq_context); 160 161 splx(s); 162 163 return 0; 164 } 165 166 void 167 taskqueue_run(struct taskqueue *queue) 168 { 169 int s; 170 struct task *task; 171 int pending; 172 173 s = splhigh(); 174 while (STAILQ_FIRST(&queue->tq_queue)) { 175 /* 176 * Carefully remove the first task from the queue and 177 * zero its pending count. 178 */ 179 task = STAILQ_FIRST(&queue->tq_queue); 180 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 181 pending = task->ta_pending; 182 task->ta_pending = 0; 183 splx(s); 184 185 task->ta_func(task->ta_context, pending); 186 187 s = splhigh(); 188 } 189 splx(s); 190 } 191 192 static void 193 taskqueue_swi_enqueue(void *context) 194 { 195 swi_sched(taskqueue_ih, SWI_NOSWITCH); 196 } 197 198 static void 199 taskqueue_swi_run(void *dummy) 200 { 201 taskqueue_run(taskqueue_swi); 202 } 203 204 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 205 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 0, 206 &taskqueue_ih)); 207