1 /* 2 * Copyright (c) 2014 Imre Vadász 3 * Copyright (c) 2014-2018 François Tigeot <ftigeot@wolfpond.org> 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 #include <asm/current.h> 34 35 typedef struct { 36 } wait_queue_t; 37 38 typedef struct { 39 struct lock lock; 40 } wait_queue_head_t; 41 42 static inline void 43 init_waitqueue_head(wait_queue_head_t *eq) 44 { 45 lockinit(&eq->lock, "lwq", 0, LK_CANRECURSE); 46 } 47 48 #define wake_up(eq) wakeup_one(eq) 49 #define wake_up_all(eq) wakeup(eq) 50 #define wake_up_interruptible(eq) wakeup_one(eq) 51 #define wake_up_interruptible_all(eq) wakeup(eq) 52 53 /* 54 * wait_event_interruptible_timeout: 55 * - The process is put to sleep until the condition evaluates to true. 56 * - The condition is checked each time the waitqueue wq is woken up. 57 * - wake_up has to be called after changing any variable that could change 58 * the result of the wait condition. 59 * 60 * returns: 61 * - 0 if the timeout elapsed 62 * - the remaining jiffies if the condition evaluated to true before 63 * the timeout elapsed. 64 * - remaining jiffies are always at least 1 65 * - -ERESTARTSYS if interrupted by a signal (when PCATCH is set in flags) 66 */ 67 #define __wait_event_common(wq, condition, timeout_jiffies, flags) \ 68 ({ \ 69 int start_jiffies, elapsed_jiffies, remaining_jiffies, ret; \ 70 bool timeout_expired = false; \ 71 bool interrupted = false; \ 72 long retval; \ 73 \ 74 start_jiffies = ticks; \ 75 \ 76 lockmgr(&wq.lock, LK_EXCLUSIVE); \ 77 while (1) { \ 78 if (condition) \ 79 break; \ 80 \ 81 ret = lksleep(&wq, &wq.lock, flags, \ 82 "lwe", timeout_jiffies); \ 83 if (ret == EINTR || ret == ERESTART) { \ 84 interrupted = true; \ 85 break; \ 86 } \ 87 if (ret == EWOULDBLOCK) { \ 88 timeout_expired = true; \ 89 break; \ 90 } \ 91 } \ 92 lockmgr(&wq.lock, LK_RELEASE); \ 93 \ 94 elapsed_jiffies = ticks - start_jiffies; \ 95 remaining_jiffies = timeout_jiffies - elapsed_jiffies; \ 96 if (remaining_jiffies <= 0) \ 97 remaining_jiffies = 1; \ 98 \ 99 if (timeout_expired) \ 100 retval = 0; \ 101 else if (interrupted) \ 102 retval = -ERESTARTSYS; \ 103 else if (timeout_jiffies > 0) \ 104 retval = remaining_jiffies; \ 105 else \ 106 retval = 1; \ 107 \ 108 retval; \ 109 }) 110 111 #define wait_event(wq, condition) \ 112 __wait_event_common(wq, condition, 0, 0) 113 114 #define wait_event_timeout(wq, condition, timeout) \ 115 __wait_event_common(wq, condition, timeout, 0) 116 117 #define wait_event_interruptible(wq, condition) \ 118 ({ \ 119 long retval; \ 120 \ 121 retval = __wait_event_common(wq, condition, 0, PCATCH); \ 122 if (retval != -ERESTARTSYS) \ 123 retval = 0; \ 124 retval; \ 125 }) 126 127 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 128 __wait_event_common(wq, condition, timeout, PCATCH) 129 130 static inline int 131 waitqueue_active(wait_queue_head_t *q) 132 { 133 return 0; /* XXX: not really implemented */ 134 } 135 136 #define DEFINE_WAIT(name) \ 137 wait_queue_t name = {} 138 139 static inline void 140 prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) 141 { 142 } 143 144 static inline void 145 finish_wait(wait_queue_head_t *q, wait_queue_t *wait) 146 { 147 } 148 149 static inline void 150 add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait) 151 { 152 } 153 154 #define DECLARE_WAIT_QUEUE_HEAD(name) \ 155 wait_queue_head_t name = { \ 156 .lock = LOCK_INITIALIZER("name", 0, LK_CANRECURSE) \ 157 } 158 159 #endif /* _LINUX_WAIT_H_ */ 160