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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/bus.h> 33 #include <sys/interrupt.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/mutex.h> 38 #include <sys/taskqueue.h> 39 40 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 41 42 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 43 44 static void *taskqueue_ih; 45 static void *taskqueue_giant_ih; 46 static struct mtx taskqueue_queues_mutex; 47 48 struct taskqueue { 49 STAILQ_ENTRY(taskqueue) tq_link; 50 STAILQ_HEAD(, task) tq_queue; 51 const char *tq_name; 52 taskqueue_enqueue_fn tq_enqueue; 53 void *tq_context; 54 int tq_draining; 55 struct mtx tq_mutex; 56 }; 57 58 static void init_taskqueue_list(void *data); 59 60 static void 61 init_taskqueue_list(void *data __unused) 62 { 63 64 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF); 65 STAILQ_INIT(&taskqueue_queues); 66 } 67 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list, 68 NULL); 69 70 struct taskqueue * 71 taskqueue_create(const char *name, int mflags, 72 taskqueue_enqueue_fn enqueue, void *context) 73 { 74 struct taskqueue *queue; 75 76 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 77 if (!queue) 78 return 0; 79 80 STAILQ_INIT(&queue->tq_queue); 81 queue->tq_name = name; 82 queue->tq_enqueue = enqueue; 83 queue->tq_context = context; 84 queue->tq_draining = 0; 85 mtx_init(&queue->tq_mutex, "taskqueue", NULL, MTX_DEF); 86 87 mtx_lock(&taskqueue_queues_mutex); 88 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 89 mtx_unlock(&taskqueue_queues_mutex); 90 91 return queue; 92 } 93 94 void 95 taskqueue_free(struct taskqueue *queue) 96 { 97 98 mtx_lock(&queue->tq_mutex); 99 KASSERT(queue->tq_draining == 0, ("free'ing a draining taskqueue")); 100 queue->tq_draining = 1; 101 mtx_unlock(&queue->tq_mutex); 102 103 taskqueue_run(queue); 104 105 mtx_lock(&taskqueue_queues_mutex); 106 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 107 mtx_unlock(&taskqueue_queues_mutex); 108 109 mtx_destroy(&queue->tq_mutex); 110 free(queue, M_TASKQUEUE); 111 } 112 113 /* 114 * Returns with the taskqueue locked. 115 */ 116 struct taskqueue * 117 taskqueue_find(const char *name) 118 { 119 struct taskqueue *queue; 120 121 mtx_lock(&taskqueue_queues_mutex); 122 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 123 mtx_lock(&queue->tq_mutex); 124 if (!strcmp(queue->tq_name, name)) { 125 mtx_unlock(&taskqueue_queues_mutex); 126 return queue; 127 } 128 mtx_unlock(&queue->tq_mutex); 129 } 130 mtx_unlock(&taskqueue_queues_mutex); 131 return 0; 132 } 133 134 int 135 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 136 { 137 struct task *ins; 138 struct task *prev; 139 140 mtx_lock(&queue->tq_mutex); 141 142 /* 143 * Don't allow new tasks on a queue which is being freed. 144 */ 145 if (queue->tq_draining) { 146 mtx_unlock(&queue->tq_mutex); 147 return EPIPE; 148 } 149 150 /* 151 * Count multiple enqueues. 152 */ 153 if (task->ta_pending) { 154 task->ta_pending++; 155 mtx_unlock(&queue->tq_mutex); 156 return 0; 157 } 158 159 /* 160 * Optimise the case when all tasks have the same priority. 161 */ 162 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 163 if (!prev || prev->ta_priority >= task->ta_priority) { 164 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 165 } else { 166 prev = 0; 167 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 168 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 169 if (ins->ta_priority < task->ta_priority) 170 break; 171 172 if (prev) 173 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 174 else 175 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 176 } 177 178 task->ta_pending = 1; 179 if (queue->tq_enqueue) 180 queue->tq_enqueue(queue->tq_context); 181 182 mtx_unlock(&queue->tq_mutex); 183 184 return 0; 185 } 186 187 void 188 taskqueue_run(struct taskqueue *queue) 189 { 190 struct task *task; 191 int pending; 192 193 mtx_lock(&queue->tq_mutex); 194 while (STAILQ_FIRST(&queue->tq_queue)) { 195 /* 196 * Carefully remove the first task from the queue and 197 * zero its pending count. 198 */ 199 task = STAILQ_FIRST(&queue->tq_queue); 200 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 201 pending = task->ta_pending; 202 task->ta_pending = 0; 203 mtx_unlock(&queue->tq_mutex); 204 205 task->ta_func(task->ta_context, pending); 206 207 mtx_lock(&queue->tq_mutex); 208 } 209 mtx_unlock(&queue->tq_mutex); 210 } 211 212 static void 213 taskqueue_swi_enqueue(void *context) 214 { 215 swi_sched(taskqueue_ih, 0); 216 } 217 218 static void 219 taskqueue_swi_run(void *dummy) 220 { 221 taskqueue_run(taskqueue_swi); 222 } 223 224 static void 225 taskqueue_swi_giant_enqueue(void *context) 226 { 227 swi_sched(taskqueue_giant_ih, 0); 228 } 229 230 static void 231 taskqueue_swi_giant_run(void *dummy) 232 { 233 taskqueue_run(taskqueue_swi_giant); 234 } 235 236 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 237 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 238 INTR_MPSAFE, &taskqueue_ih)); 239 240 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, 241 swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run, 242 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 243