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| 1 | jermar | 1 | /* |
| 2 | * Copyright (C) 2001-2004 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 1702 | cejka | 29 | /** @addtogroup sync Synchronization |
| 30 | * @ingroup kernel |
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| 31 | * @{ |
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| 32 | */ |
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| 33 | |||
| 1264 | jermar | 34 | /** |
| 1702 | cejka | 35 | * @file |
| 1264 | jermar | 36 | * @brief Condition variables. |
| 37 | */ |
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| 38 | |||
| 1 | jermar | 39 | #include <synch/condvar.h> |
| 40 | #include <synch/mutex.h> |
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| 41 | #include <synch/waitq.h> |
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| 387 | jermar | 42 | #include <synch/synch.h> |
| 1375 | jermar | 43 | #include <arch.h> |
| 44 | #include <typedefs.h> |
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| 1 | jermar | 45 | |
| 1375 | jermar | 46 | /** Initialize condition variable. |
| 387 | jermar | 47 | * |
| 48 | * @param cv Condition variable. |
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| 49 | */ |
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| 1 | jermar | 50 | void condvar_initialize(condvar_t *cv) |
| 51 | { |
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| 52 | waitq_initialize(&cv->wq); |
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| 53 | } |
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| 54 | |||
| 1375 | jermar | 55 | /** |
| 387 | jermar | 56 | * Signal the condition has become true |
| 57 | * to the first waiting thread by waking it up. |
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| 58 | * |
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| 404 | jermar | 59 | * @param cv Condition variable. |
| 387 | jermar | 60 | */ |
| 1 | jermar | 61 | void condvar_signal(condvar_t *cv) |
| 62 | { |
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| 63 | waitq_wakeup(&cv->wq, WAKEUP_FIRST); |
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| 64 | } |
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| 65 | |||
| 1375 | jermar | 66 | /** |
| 387 | jermar | 67 | * Signal the condition has become true |
| 68 | * to all waiting threads by waking them up. |
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| 69 | * |
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| 404 | jermar | 70 | * @param cv Condition variable. |
| 387 | jermar | 71 | */ |
| 1 | jermar | 72 | void condvar_broadcast(condvar_t *cv) |
| 73 | { |
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| 74 | waitq_wakeup(&cv->wq, WAKEUP_ALL); |
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| 75 | } |
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| 76 | |||
| 1375 | jermar | 77 | /** Wait for the condition becoming true. |
| 387 | jermar | 78 | * |
| 404 | jermar | 79 | * @param cv Condition variable. |
| 80 | * @param mtx Mutex. |
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| 81 | * @param usec Timeout value in microseconds. |
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| 1502 | jermar | 82 | * @param flags Select mode of operation. |
| 404 | jermar | 83 | * |
| 1502 | jermar | 84 | * For exact description of meaning of possible combinations |
| 85 | * of usec and flags, see comment for waitq_sleep_timeout(). |
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| 86 | * Note that when SYNCH_FLAGS_NON_BLOCKING is specified here, |
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| 87 | * ESYNCH_WOULD_BLOCK is always returned. |
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| 404 | jermar | 88 | * |
| 89 | * @return See comment for waitq_sleep_timeout(). |
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| 387 | jermar | 90 | */ |
| 1502 | jermar | 91 | int _condvar_wait_timeout(condvar_t *cv, mutex_t *mtx, __u32 usec, int flags) |
| 1 | jermar | 92 | { |
| 93 | int rc; |
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| 1375 | jermar | 94 | ipl_t ipl; |
| 1 | jermar | 95 | |
| 1375 | jermar | 96 | ipl = waitq_sleep_prepare(&cv->wq); |
| 1 | jermar | 97 | mutex_unlock(mtx); |
| 1375 | jermar | 98 | |
| 1416 | jermar | 99 | cv->wq.missed_wakeups = 0; /* Enforce blocking. */ |
| 1502 | jermar | 100 | rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags); |
| 1416 | jermar | 101 | |
| 1 | jermar | 102 | mutex_lock(mtx); |
| 1375 | jermar | 103 | waitq_sleep_finish(&cv->wq, rc, ipl); |
| 104 | |||
| 1 | jermar | 105 | return rc; |
| 106 | } |
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| 1702 | cejka | 107 | |
| 108 | /** @} |
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| 109 | */ |
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| 110 |