1 /* 2 * Copyright (c) 2019-2020 François Tigeot <ftigeot@wolfpond.org> 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 unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <linux/wait.h> 28 #include <linux/sched.h> 29 30 int 31 default_wake_function(wait_queue_t *q, unsigned mode, int wake_flags, void *key) 32 { 33 return wake_up_process(q->private); 34 } 35 36 int 37 autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key) 38 { 39 int ret = default_wake_function(wait, mode, sync, key); 40 41 /* Was the process woken up ? */ 42 if (ret) 43 list_del_init(&wait->task_list); 44 45 return ret; 46 } 47 48 void 49 __wake_up_core(wait_queue_head_t *q, int num_to_wake_up) 50 { 51 wait_queue_t *curr, *next; 52 int mode = TASK_NORMAL; 53 54 list_for_each_entry_safe(curr, next, &q->task_list, task_list) { 55 if (curr->func(curr, mode, 0, NULL)) 56 num_to_wake_up--; 57 58 if (num_to_wake_up == 0) 59 break; 60 } 61 } 62 63 void 64 __wait_event_prefix(wait_queue_head_t *wq, int flags) 65 { 66 lockmgr(&wq->lock, LK_EXCLUSIVE); 67 if (flags & PCATCH) { 68 set_current_state(TASK_INTERRUPTIBLE); 69 } else { 70 set_current_state(TASK_UNINTERRUPTIBLE); 71 } 72 lockmgr(&wq->lock, LK_RELEASE); 73 } 74 75 void 76 prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) 77 { 78 lockmgr(&q->lock, LK_EXCLUSIVE); 79 if (list_empty(&wait->task_list)) 80 __add_wait_queue(q, wait); 81 set_current_state(state); 82 lockmgr(&q->lock, LK_RELEASE); 83 } 84 85 void 86 finish_wait(wait_queue_head_t *q, wait_queue_t *wait) 87 { 88 set_current_state(TASK_RUNNING); 89 90 lockmgr(&q->lock, LK_EXCLUSIVE); 91 if (!list_empty(&wait->task_list)) 92 list_del_init(&wait->task_list); 93 lockmgr(&q->lock, LK_RELEASE); 94 } 95 96 void 97 wake_up_bit(void *addr, int bit) 98 { 99 wakeup_one(addr); 100 } 101 102 /* Wait for a bit to be cleared or a timeout to expire */ 103 int 104 wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode, 105 unsigned long timeout) 106 { 107 int rv, awakened = 0, timeout_expired = 0; 108 long start_time; 109 110 if (!test_bit(bit, word)) 111 return 0; 112 113 start_time = ticks; 114 set_current_state(mode); 115 116 do { 117 rv = tsleep(word, mode, "lwobt", timeout); 118 if (rv == 0) 119 awakened = 1; 120 if (time_after_eq(start_time, timeout)) 121 timeout_expired = 1; 122 } while (test_bit(bit, word) && !timeout_expired); 123 124 set_current_state(TASK_RUNNING); 125 126 if (awakened) 127 return 0; 128 129 return 1; 130 } 131