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 #ifndef _LINUX_COMPLETION_H_ 27 #define _LINUX_COMPLETION_H_ 28 29 #include <linux/wait.h> 30 31 struct completion { 32 unsigned int done; 33 wait_queue_head_t wait; 34 }; 35 36 static inline void 37 init_completion(struct completion *c) 38 { 39 c->done = 0; 40 init_waitqueue_head(&c->wait); 41 } 42 43 #define INIT_COMPLETION(c) (c.done = 0) 44 45 /* 46 * Completion interlock and wakeup. Be careful not to execute the wakeup 47 * from inside the spinlock as this can deadlock if the IPIQ fifo is full. 48 * (also note that wakeup() is asynchronous anyway, so no point doing that). 49 */ 50 static inline void 51 complete(struct completion *c) 52 { 53 spin_lock(&c->wait.lock); 54 c->done++; 55 spin_unlock(&c->wait.lock); 56 wakeup_one(&c->wait); 57 } 58 59 static inline void 60 complete_all(struct completion *c) 61 { 62 spin_lock(&c->wait.lock); 63 c->done++; 64 spin_unlock(&c->wait.lock); 65 wakeup(&c->wait); 66 } 67 68 static inline long 69 wait_for_completion_interruptible_timeout(struct completion *x, 70 unsigned long timeout) 71 { 72 int start_jiffies, elapsed_jiffies, remaining_jiffies; 73 bool timeout_expired = false, awakened = false; 74 long ret = 1; 75 76 start_jiffies = ticks; 77 78 spin_lock(&x->wait.lock); 79 while (x->done == 0 && !timeout_expired) { 80 ret = ssleep(&x->wait, &x->wait.lock, PCATCH, "wfcit", timeout); 81 switch(ret) { 82 case EWOULDBLOCK: 83 timeout_expired = true; 84 ret = 0; 85 break; 86 case ERESTART: 87 ret = -ERESTARTSYS; 88 break; 89 case 0: 90 awakened = true; 91 break; 92 } 93 } 94 spin_unlock(&x->wait.lock); 95 96 if (awakened) { 97 elapsed_jiffies = ticks - start_jiffies; 98 remaining_jiffies = timeout - elapsed_jiffies; 99 if (remaining_jiffies > 0) 100 ret = remaining_jiffies; 101 } 102 103 return ret; 104 } 105 106 #endif /* _LINUX_COMPLETION_H_ */ 107