1 /* 2 * Copyright (c) 2014 Imre Vadász 3 * Copyright (c) 2014-2019 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/stddef.h> 33 #include <linux/spinlock.h> 34 #include <asm/current.h> 35 36 typedef struct __wait_queue wait_queue_t; 37 38 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key); 39 40 struct __wait_queue { 41 unsigned int flags; 42 void *private; 43 wait_queue_func_t func; 44 }; 45 46 typedef struct { 47 struct lock lock; 48 } wait_queue_head_t; 49 50 static inline void 51 init_waitqueue_head(wait_queue_head_t *eq) 52 { 53 lockinit(&eq->lock, "lwq", 0, LK_CANRECURSE); 54 } 55 56 #define wake_up(eq) wakeup_one(eq) 57 #define wake_up_all(eq) wakeup(eq) 58 #define wake_up_all_locked(eq) wakeup(eq) 59 #define wake_up_interruptible(eq) wakeup_one(eq) 60 #define wake_up_interruptible_all(eq) wakeup(eq) 61 62 /* 63 * wait_event_interruptible_timeout: 64 * - The process is put to sleep until the condition evaluates to true. 65 * - The condition is checked each time the waitqueue wq is woken up. 66 * - wake_up has to be called after changing any variable that could change 67 * the result of the wait condition. 68 * 69 * returns: 70 * - 0 if the timeout elapsed 71 * - the remaining jiffies if the condition evaluated to true before 72 * the timeout elapsed. 73 * - remaining jiffies are always at least 1 74 * - -ERESTARTSYS if interrupted by a signal (when PCATCH is set in flags) 75 */ 76 #define __wait_event_common(wq, condition, timeout_jiffies, flags) \ 77 ({ \ 78 int start_jiffies, elapsed_jiffies, remaining_jiffies, ret; \ 79 bool timeout_expired = false; \ 80 bool interrupted = false; \ 81 long retval; \ 82 \ 83 start_jiffies = ticks; \ 84 \ 85 lockmgr(&wq.lock, LK_EXCLUSIVE); \ 86 while (1) { \ 87 if (condition) \ 88 break; \ 89 \ 90 ret = lksleep(&wq, &wq.lock, flags, \ 91 "lwe", timeout_jiffies); \ 92 if (ret == EINTR || ret == ERESTART) { \ 93 interrupted = true; \ 94 break; \ 95 } \ 96 if (ret == EWOULDBLOCK) { \ 97 timeout_expired = true; \ 98 break; \ 99 } \ 100 } \ 101 lockmgr(&wq.lock, LK_RELEASE); \ 102 \ 103 elapsed_jiffies = ticks - start_jiffies; \ 104 remaining_jiffies = timeout_jiffies - elapsed_jiffies; \ 105 if (remaining_jiffies <= 0) \ 106 remaining_jiffies = 1; \ 107 \ 108 if (timeout_expired) \ 109 retval = 0; \ 110 else if (interrupted) \ 111 retval = -ERESTARTSYS; \ 112 else if (timeout_jiffies > 0) \ 113 retval = remaining_jiffies; \ 114 else \ 115 retval = 1; \ 116 \ 117 retval; \ 118 }) 119 120 #define wait_event(wq, condition) \ 121 __wait_event_common(wq, condition, 0, 0) 122 123 #define wait_event_timeout(wq, condition, timeout) \ 124 __wait_event_common(wq, condition, timeout, 0) 125 126 #define wait_event_interruptible(wq, condition) \ 127 ({ \ 128 long retval; \ 129 \ 130 retval = __wait_event_common(wq, condition, 0, PCATCH); \ 131 if (retval != -ERESTARTSYS) \ 132 retval = 0; \ 133 retval; \ 134 }) 135 136 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 137 __wait_event_common(wq, condition, timeout, PCATCH) 138 139 static inline int 140 waitqueue_active(wait_queue_head_t *q) 141 { 142 return 0; /* XXX: not really implemented */ 143 } 144 145 #define DEFINE_WAIT(name) \ 146 wait_queue_t name = {} 147 148 static inline void 149 prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) 150 { 151 } 152 153 static inline void 154 finish_wait(wait_queue_head_t *q, wait_queue_t *wait) 155 { 156 } 157 158 static inline void 159 add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait) 160 { 161 } 162 163 static inline void 164 __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new) 165 { 166 } 167 168 #define DECLARE_WAIT_QUEUE_HEAD(name) \ 169 wait_queue_head_t name = { \ 170 .lock = LOCK_INITIALIZER("name", 0, LK_CANRECURSE) \ 171 } 172 173 static inline void 174 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old) 175 { 176 } 177 178 #endif /* _LINUX_WAIT_H_ */ 179