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); 41 } 42 43 #define wake_up_all(eq) wakeup(eq) 44 45 /* 46 * wait_event_timeout: 47 * - The process is put to sleep until the condition evaluates to true. 48 * - The condition is checked each time the waitqueue wq is woken up. 49 * - wake_up has to be called after changing any variable that could change 50 * the result of the wait condition. 51 * 52 * returns: 53 * - 0 if the timeout elapsed 54 * - the remaining jiffies if the condition evaluated to true before 55 * the timeout elapsed. 56 * - remaining jiffies are always at least 1 57 */ 58 #define __wait_event_common(wq, condition, timeout_jiffies, flags) \ 59 ({ \ 60 int start_jiffies, elapsed_jiffies, remaining_jiffies; \ 61 bool timeout_expired = false; \ 62 long retval; \ 63 \ 64 start_jiffies = ticks; \ 65 \ 66 spin_lock(&wq.lock); \ 67 while (1) { \ 68 if (condition) \ 69 break; \ 70 \ 71 ret = ssleep(&wq, &wq.lock, flags, \ 72 "lwe", timeout_jiffies); \ 73 if (ret == EWOULDBLOCK) { \ 74 timeout_expired = true; \ 75 break; \ 76 } \ 77 } \ 78 spin_unlock(&wq.lock); \ 79 \ 80 elapsed_jiffies = ticks - start_jiffies; \ 81 remaining_jiffies = timeout_jiffies - elapsed_jiffies; \ 82 if (remaining_jiffies == 0) \ 83 remaining_jiffies = 1; \ 84 \ 85 if (timeout_expired) \ 86 retval = 0; \ 87 else \ 88 retval = remaining_jiffies; \ 89 \ 90 retval; \ 91 }) 92 93 #define wait_event_timeout(wq, condition, timeout) \ 94 __wait_event_common(wq, condition, timeout, 0) 95 96 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 97 __wait_event_common(wq, condition, timeout, PCATCH) 98 99 #endif /* _LINUX_WAIT_H_ */ 100