iconv: Suppress array out of bounds warning.
[platform/upstream/glibc.git] / nptl / pthread_rwlock_unlock.c
1 /* Copyright (C) 2003-2015 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 #include <stap-probe.h>
25 #include <elide.h>
26
27
28 /* Unlock RWLOCK.  */
29 int
30 __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
31 {
32   LIBC_PROBE (rwlock_unlock, 1, rwlock);
33
34   if (ELIDE_UNLOCK (rwlock->__data.__writer == 0
35                     && rwlock->__data.__nr_readers == 0))
36     return 0;
37
38   lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
39   if (rwlock->__data.__writer)
40     rwlock->__data.__writer = 0;
41   else
42     --rwlock->__data.__nr_readers;
43   if (rwlock->__data.__nr_readers == 0)
44     {
45       if (rwlock->__data.__nr_writers_queued)
46         {
47           ++rwlock->__data.__writer_wakeup;
48           lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
49           lll_futex_wake (&rwlock->__data.__writer_wakeup, 1,
50                           rwlock->__data.__shared);
51           return 0;
52         }
53       else if (rwlock->__data.__nr_readers_queued)
54         {
55           ++rwlock->__data.__readers_wakeup;
56           lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
57           lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
58                           rwlock->__data.__shared);
59           return 0;
60         }
61     }
62   lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
63   return 0;
64 }
65
66 weak_alias (__pthread_rwlock_unlock, pthread_rwlock_unlock)
67 hidden_def (__pthread_rwlock_unlock)