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/kern/subr_taskqueue.c,v 1.1.2.2 2001/03/31 03:33:44 hsu Exp $ 27 * $DragonFly: src/sys/kern/subr_taskqueue.c,v 1.3 2003/06/29 03:28:44 dillon Exp $ 28 */ 29 30 #include <sys/param.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 #include <machine/ipl.h> 38 39 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 40 41 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 42 43 struct taskqueue { 44 STAILQ_ENTRY(taskqueue) tq_link; 45 STAILQ_HEAD(, task) tq_queue; 46 const char *tq_name; 47 taskqueue_enqueue_fn tq_enqueue; 48 void *tq_context; 49 int tq_draining; 50 }; 51 52 struct taskqueue * 53 taskqueue_create(const char *name, int mflags, 54 taskqueue_enqueue_fn enqueue, void *context) 55 { 56 struct taskqueue *queue; 57 static int once = 1; 58 int s; 59 60 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags); 61 if (!queue) 62 return 0; 63 STAILQ_INIT(&queue->tq_queue); 64 queue->tq_name = name; 65 queue->tq_enqueue = enqueue; 66 queue->tq_context = context; 67 queue->tq_draining = 0; 68 69 s = splhigh(); 70 if (once) { 71 STAILQ_INIT(&taskqueue_queues); 72 once = 0; 73 } 74 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 75 splx(s); 76 77 return queue; 78 } 79 80 void 81 taskqueue_free(struct taskqueue *queue) 82 { 83 int s = splhigh(); 84 queue->tq_draining = 1; 85 splx(s); 86 87 taskqueue_run(queue); 88 89 s = splhigh(); 90 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 91 splx(s); 92 93 free(queue, M_TASKQUEUE); 94 } 95 96 struct taskqueue * 97 taskqueue_find(const char *name) 98 { 99 struct taskqueue *queue; 100 int s; 101 102 s = splhigh(); 103 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) 104 if (!strcmp(queue->tq_name, name)) { 105 splx(s); 106 return queue; 107 } 108 splx(s); 109 return 0; 110 } 111 112 int 113 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 114 { 115 struct task *ins; 116 struct task *prev; 117 118 int s = splhigh(); 119 120 /* 121 * Don't allow new tasks on a queue which is being freed. 122 */ 123 if (queue->tq_draining) { 124 splx(s); 125 return EPIPE; 126 } 127 128 /* 129 * Count multiple enqueues. 130 */ 131 if (task->ta_pending) { 132 task->ta_pending++; 133 splx(s); 134 return 0; 135 } 136 137 /* 138 * Optimise the case when all tasks have the same priority. 139 */ 140 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 141 if (!prev || prev->ta_priority >= task->ta_priority) { 142 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 143 } else { 144 prev = 0; 145 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 146 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 147 if (ins->ta_priority < task->ta_priority) 148 break; 149 150 if (prev) 151 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 152 else 153 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 154 } 155 156 task->ta_pending = 1; 157 if (queue->tq_enqueue) 158 queue->tq_enqueue(queue->tq_context); 159 160 splx(s); 161 162 return 0; 163 } 164 165 void 166 taskqueue_run(struct taskqueue *queue) 167 { 168 int s; 169 struct task *task; 170 int pending; 171 172 s = splhigh(); 173 while (STAILQ_FIRST(&queue->tq_queue)) { 174 /* 175 * Carefully remove the first task from the queue and 176 * zero its pending count. 177 */ 178 task = STAILQ_FIRST(&queue->tq_queue); 179 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 180 pending = task->ta_pending; 181 task->ta_pending = 0; 182 splx(s); 183 184 task->ta_func(task->ta_context, pending); 185 186 s = splhigh(); 187 } 188 splx(s); 189 } 190 191 static void 192 taskqueue_swi_enqueue(void *context) 193 { 194 setsofttq(); 195 } 196 197 static void 198 taskqueue_swi_run(void *arg) 199 { 200 taskqueue_run(taskqueue_swi); 201 } 202 203 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 204 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq")); 205