1 /* Copyright (C) 2003, 2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19 #include <errno.h>
20 #include <sysdep.h>
21 #include <lowlevellock.h>
22 #include <pthread.h>
23 #include <pthreadP.h>
24
25 /* Unlock RWLOCK. */
26 int
27 attribute_protected
__pthread_rwlock_unlock(pthread_rwlock_t * rwlock)28 __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
29 {
30 lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
31 if (rwlock->__data.__writer)
32 rwlock->__data.__writer = 0;
33 else
34 --rwlock->__data.__nr_readers;
35 if (rwlock->__data.__nr_readers == 0)
36 {
37 if (rwlock->__data.__nr_writers_queued)
38 {
39 ++rwlock->__data.__writer_wakeup;
40 lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
41 lll_futex_wake (&rwlock->__data.__writer_wakeup, 1,
42 rwlock->__data.__shared);
43 return 0;
44 }
45 else if (rwlock->__data.__nr_readers_queued)
46 {
47 ++rwlock->__data.__readers_wakeup;
48 lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
49 lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
50 rwlock->__data.__shared);
51 return 0;
52 }
53 }
54 lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
55 return 0;
56 }
57
58 weak_alias (__pthread_rwlock_unlock, pthread_rwlock_unlock)
59 strong_alias (__pthread_rwlock_unlock, __pthread_rwlock_unlock_internal)
60