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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  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.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - 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.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <synch/condvar.h>
  30. #include <synch/mutex.h>
  31. #include <synch/waitq.h>
  32. #include <synch/synch.h>
  33.  
  34. /** Initialize condition variable
  35.  *
  36.  * Initialize condition variable.
  37.  *
  38.  * @param cv Condition variable.
  39.  */
  40. void condvar_initialize(condvar_t *cv)
  41. {
  42.     waitq_initialize(&cv->wq);
  43. }
  44.  
  45. /** Signal the condition has become true
  46.  *
  47.  * Signal the condition has become true
  48.  * to the first waiting thread by waking it up.
  49.  *
  50.  * @param cv Condition variable.
  51.  */
  52. void condvar_signal(condvar_t *cv)
  53. {
  54.     waitq_wakeup(&cv->wq, WAKEUP_FIRST);
  55. }
  56.  
  57. /** Signal the condition has become true
  58.  *
  59.  * Signal the condition has become true
  60.  * to all waiting threads by waking them up.
  61.  *
  62.  * @param cv Condition variable.
  63.  */
  64. void condvar_broadcast(condvar_t *cv)
  65. {
  66.     waitq_wakeup(&cv->wq, WAKEUP_ALL);
  67. }
  68.  
  69. /** Wait for the condition becoming true
  70.  *
  71.  * Wait for the condition becoming true.
  72.  *
  73.  * @param cv Condition variable.
  74.  * @param mtx Mutex.
  75.  * @param usec Timeout value in microseconds.
  76.  * @param trywait Blocking versus non-blocking operation mode switch.
  77.  *
  78.  * For exact description of possible combinations of
  79.  * 'usec' and 'trywait', see comment for waitq_sleep_timeout().
  80.  *
  81.  * @return See comment for waitq_sleep_timeout().
  82.  */
  83. int _condvar_wait_timeout(condvar_t *cv, mutex_t *mtx, __u32 usec, int trywait)
  84. {
  85.     int rc;
  86.  
  87.     mutex_unlock(mtx);
  88.     rc = waitq_sleep_timeout(&cv->wq, usec, trywait);
  89.     mutex_lock(mtx);
  90.     return rc;
  91. }
  92.