1 /* 2 * Copyright (c) 2014 François Tigeot 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 #ifndef _LINUX_WAIT_H_ 28 #define _LINUX_WAIT_H_ 29 30 #include <sys/spinlock2.h> 31 #include <sys/param.h> 32 33 typedef struct { 34 struct spinlock lock; 35 } wait_queue_head_t; 36 37 static inline void 38 init_waitqueue_head(wait_queue_head_t *eq) 39 { 40 spin_init(&eq->lock, "linux_waitqueue"); 41 } 42 43 #define wake_up(eq) wakeup_one(eq) 44 #define wake_up_all(eq) wakeup(eq) 45 46 /* 47 * wait_event_timeout: 48 * - The process is put to sleep until the condition evaluates to true. 49 * - The condition is checked each time the waitqueue wq is woken up. 50 * - wake_up has to be called after changing any variable that could change 51 * the result of the wait condition. 52 * 53 * returns: 54 * - 0 if the timeout elapsed 55 * - the remaining jiffies if the condition evaluated to true before 56 * the timeout elapsed. 57 * - remaining jiffies are always at least 1 58 */ 59 #define __wait_event_common(wq, condition, timeout_jiffies, flags) \ 60 ({ \ 61 int start_jiffies, elapsed_jiffies, remaining_jiffies, ret; \ 62 bool timeout_expired = false; \ 63 long retval; \ 64 \ 65 start_jiffies = ticks; \ 66 \ 67 spin_lock(&wq.lock); \ 68 while (1) { \ 69 if (condition) \ 70 break; \ 71 \ 72 ret = ssleep(&wq, &wq.lock, flags, \ 73 "lwe", timeout_jiffies); \ 74 if (ret == EWOULDBLOCK) { \ 75 timeout_expired = true; \ 76 break; \ 77 } \ 78 } \ 79 spin_unlock(&wq.lock); \ 80 \ 81 elapsed_jiffies = ticks - start_jiffies; \ 82 remaining_jiffies = timeout_jiffies - elapsed_jiffies; \ 83 if (remaining_jiffies == 0) \ 84 remaining_jiffies = 1; \ 85 \ 86 if (timeout_expired) \ 87 retval = 0; \ 88 else \ 89 retval = remaining_jiffies; \ 90 \ 91 retval; \ 92 }) 93 94 #define wait_event(wq, condition) \ 95 __wait_event_common(wq, condition, 0, 0) 96 97 #define wait_event_timeout(wq, condition, timeout) \ 98 __wait_event_common(wq, condition, timeout, 0) 99 100 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 101 __wait_event_common(wq, condition, timeout, PCATCH) 102 103 #endif /* _LINUX_WAIT_H_ */ 104