1 /* 2 * Copyright (c) 2014-2015 François Tigeot 3 * Copyright (c) 2014 Imre Vadász 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice unmodified, this list of conditions, and the following 11 * disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef _LINUX_WAIT_H_ 29 #define _LINUX_WAIT_H_ 30 31 #include <linux/list.h> 32 #include <linux/spinlock.h> 33 34 typedef struct { 35 } wait_queue_t; 36 37 typedef struct { 38 struct lock lock; 39 } wait_queue_head_t; 40 41 static inline void 42 init_waitqueue_head(wait_queue_head_t *eq) 43 { 44 lockinit(&eq->lock, "lwq", 0, LK_CANRECURSE); 45 } 46 47 #define wake_up(eq) wakeup_one(eq) 48 #define wake_up_all(eq) wakeup(eq) 49 #define wake_up_interruptible(eq) wakeup_one(eq) 50 #define wake_up_interruptible_all(eq) wakeup(eq) 51 52 /* 53 * wait_event_interruptible_timeout: 54 * - The process is put to sleep until the condition evaluates to true. 55 * - The condition is checked each time the waitqueue wq is woken up. 56 * - wake_up has to be called after changing any variable that could change 57 * the result of the wait condition. 58 * 59 * returns: 60 * - 0 if the timeout elapsed 61 * - the remaining jiffies if the condition evaluated to true before 62 * the timeout elapsed. 63 * - remaining jiffies are always at least 1 64 * - -ERESTARTSYS if interrupted by a signal (when PCATCH is set in flags) 65 */ 66 #define __wait_event_common(wq, condition, timeout_jiffies, flags) \ 67 ({ \ 68 int start_jiffies, elapsed_jiffies, remaining_jiffies, ret; \ 69 bool timeout_expired = false; \ 70 bool interrupted = false; \ 71 long retval; \ 72 \ 73 start_jiffies = ticks; \ 74 \ 75 lockmgr(&wq.lock, LK_EXCLUSIVE); \ 76 while (1) { \ 77 if (condition) \ 78 break; \ 79 \ 80 ret = lksleep(&wq, &wq.lock, flags, \ 81 "lwe", timeout_jiffies); \ 82 if (ret == EINTR || ret == ERESTART) { \ 83 interrupted = true; \ 84 break; \ 85 } \ 86 if (ret == EWOULDBLOCK) { \ 87 timeout_expired = true; \ 88 break; \ 89 } \ 90 } \ 91 lockmgr(&wq.lock, LK_RELEASE); \ 92 \ 93 elapsed_jiffies = ticks - start_jiffies; \ 94 remaining_jiffies = timeout_jiffies - elapsed_jiffies; \ 95 if (remaining_jiffies <= 0) \ 96 remaining_jiffies = 1; \ 97 \ 98 if (timeout_expired) \ 99 retval = 0; \ 100 else if (interrupted) \ 101 retval = -ERESTARTSYS; \ 102 else if (timeout_jiffies > 0) \ 103 retval = remaining_jiffies; \ 104 else \ 105 retval = 1; \ 106 \ 107 retval; \ 108 }) 109 110 #define wait_event(wq, condition) \ 111 __wait_event_common(wq, condition, 0, 0) 112 113 #define wait_event_timeout(wq, condition, timeout) \ 114 __wait_event_common(wq, condition, timeout, 0) 115 116 #define wait_event_interruptible(wq, condition) \ 117 ({ \ 118 long retval; \ 119 \ 120 retval = __wait_event_common(wq, condition, 0, PCATCH); \ 121 if (retval != -ERESTARTSYS) \ 122 retval = 0; \ 123 retval; \ 124 }) 125 126 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 127 __wait_event_common(wq, condition, timeout, PCATCH) 128 129 static inline int 130 waitqueue_active(wait_queue_head_t *q) 131 { 132 return 0; /* XXX: not really implemented */ 133 } 134 135 #define DEFINE_WAIT(name) \ 136 wait_queue_t name = {} 137 138 static inline void 139 prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) 140 { 141 } 142 143 static inline void 144 finish_wait(wait_queue_head_t *q, wait_queue_t *wait) 145 { 146 } 147 148 #endif /* _LINUX_WAIT_H_ */ 149