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/spinlock.h> 32 #include <sys/param.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_all(eq) wakeup(eq) 50 51 /* 52 * wait_event_interruptible_timeout: 53 * - The process is put to sleep until the condition evaluates to true. 54 * - The condition is checked each time the waitqueue wq is woken up. 55 * - wake_up has to be called after changing any variable that could change 56 * the result of the wait condition. 57 * 58 * returns: 59 * - 0 if the timeout elapsed 60 * - the remaining jiffies if the condition evaluated to true before 61 * the timeout elapsed. 62 * - remaining jiffies are always at least 1 63 * - -ERESTARTSYS if interrupted by a signal (when PCATCH is set in flags) 64 */ 65 #define __wait_event_common(wq, condition, timeout_jiffies, flags) \ 66 ({ \ 67 int start_jiffies, elapsed_jiffies, remaining_jiffies, ret; \ 68 bool timeout_expired = false; \ 69 bool interrupted = false; \ 70 long retval; \ 71 \ 72 start_jiffies = ticks; \ 73 \ 74 lockmgr(&wq.lock, LK_EXCLUSIVE); \ 75 while (1) { \ 76 if (condition) \ 77 break; \ 78 \ 79 ret = lksleep(&wq, &wq.lock, flags, \ 80 "lwe", timeout_jiffies); \ 81 if (ret == EINTR || ret == ERESTART) { \ 82 interrupted = true; \ 83 break; \ 84 } \ 85 if (ret == EWOULDBLOCK) { \ 86 timeout_expired = true; \ 87 break; \ 88 } \ 89 } \ 90 lockmgr(&wq.lock, LK_RELEASE); \ 91 \ 92 elapsed_jiffies = ticks - start_jiffies; \ 93 remaining_jiffies = timeout_jiffies - elapsed_jiffies; \ 94 if (remaining_jiffies <= 0) \ 95 remaining_jiffies = 1; \ 96 \ 97 if (timeout_expired) \ 98 retval = 0; \ 99 else if (interrupted) \ 100 retval = -ERESTARTSYS; \ 101 else if (timeout_jiffies > 0) \ 102 retval = remaining_jiffies; \ 103 else \ 104 retval = 1; \ 105 \ 106 retval; \ 107 }) 108 109 #define wait_event(wq, condition) \ 110 __wait_event_common(wq, condition, 0, 0) 111 112 #define wait_event_timeout(wq, condition, timeout) \ 113 __wait_event_common(wq, condition, timeout, 0) 114 115 #define wait_event_interruptible(wq, condition) \ 116 ({ \ 117 long retval; \ 118 \ 119 retval = __wait_event_common(wq, condition, 0, PCATCH); \ 120 if (retval != -ERESTARTSYS) \ 121 retval = 0; \ 122 retval; \ 123 }) 124 125 #define wait_event_interruptible_timeout(wq, condition, timeout) \ 126 __wait_event_common(wq, condition, timeout, PCATCH) 127 128 static inline int 129 waitqueue_active(wait_queue_head_t *q) 130 { 131 return 0; /* XXX: not really implemented */ 132 } 133 134 #define DEFINE_WAIT(name) \ 135 wait_queue_t name = {} 136 137 static inline void 138 prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) 139 { 140 } 141 142 static inline void 143 finish_wait(wait_queue_head_t *q, wait_queue_t *wait) 144 { 145 } 146 147 #endif /* _LINUX_WAIT_H_ */ 148