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