2 * Copyright (c) 2019-2020 François Tigeot <ftigeot@wolfpond.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
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.
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.
27 #include <linux/wait.h>
28 #include <linux/wait_bit.h>
29 #include <linux/sched.h>
32 default_wake_function(wait_queue_entry_t *q, unsigned mode, int wake_flags, void *key)
34 return wake_up_process(q->private);
38 autoremove_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
40 int ret = default_wake_function(wait, mode, sync, key);
42 /* Was the process woken up ? */
44 list_del_init(&wait->entry);
50 __wake_up_core(wait_queue_head_t *q, int num_to_wake_up)
52 wait_queue_entry_t *curr, *next;
53 int mode = TASK_NORMAL;
55 list_for_each_entry_safe(curr, next, &q->head, entry) {
56 if (curr->func(curr, mode, 0, NULL))
59 if (num_to_wake_up == 0)
65 __wait_event_prefix(wait_queue_head_t *wq, int flags)
67 lockmgr(&wq->lock, LK_EXCLUSIVE);
69 set_current_state(TASK_INTERRUPTIBLE);
71 set_current_state(TASK_UNINTERRUPTIBLE);
73 lockmgr(&wq->lock, LK_RELEASE);
77 prepare_to_wait(wait_queue_head_t *q, wait_queue_entry_t *wait, int state)
79 lockmgr(&q->lock, LK_EXCLUSIVE);
80 if (list_empty(&wait->entry))
81 __add_wait_queue(q, wait);
82 set_current_state(state);
83 lockmgr(&q->lock, LK_RELEASE);
87 finish_wait(wait_queue_head_t *q, wait_queue_entry_t *wait)
89 set_current_state(TASK_RUNNING);
91 lockmgr(&q->lock, LK_EXCLUSIVE);
92 if (!list_empty(&wait->entry))
93 list_del_init(&wait->entry);
94 lockmgr(&q->lock, LK_RELEASE);
98 wake_up_bit(void *addr, int bit)
103 /* Wait for a bit to be cleared or a timeout to expire */
105 wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode,
106 unsigned long timeout)
108 int rv, awakened = 0, timeout_expired = 0;
111 if (!test_bit(bit, word))
115 set_current_state(mode);
118 rv = tsleep(word, mode, "lwobt", timeout);
121 if (time_after_eq(start_time, timeout))
123 } while (test_bit(bit, word) && !timeout_expired);
125 set_current_state(TASK_RUNNING);
133 void __init_waitqueue_head(wait_queue_head_t *q,
134 const char *name, struct lock_class_key *key)
136 lockinit(&q->lock, "lwq", 0, 0);
137 INIT_LIST_HEAD(&q->head);
141 wait_on_bit(unsigned long *word, int bit, unsigned mode)
143 return wait_on_bit_timeout(word, bit, mode, MAX_SCHEDULE_TIMEOUT);
147 init_wait_entry(struct wait_queue_entry *wq_entry, int flags)
149 INIT_LIST_HEAD(&wq_entry->entry);
150 wq_entry->flags = flags;
151 wq_entry->private = current;
152 wq_entry->func = autoremove_wake_function;