Update.
[glibc.git] / nptl / pthread_mutex_timedlock.c
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1 /* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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.
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.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <errno.h>
21 #include "pthreadP.h"
22 #include <lowlevellock.h>
25 int
26 pthread_mutex_timedlock (mutex, abstime)
27 pthread_mutex_t *mutex;
28 const struct timespec *abstime;
30 pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
31 int result = 0;
33 /* We must not check ABSTIME here. If the thread does not block
34 abstime must not be checked for a valid value. */
36 switch (mutex->__data.__kind)
38 /* Recursive mutex. */
39 case PTHREAD_MUTEX_RECURSIVE_NP:
40 /* Check whether we already hold the mutex. */
41 if (mutex->__data.__owner == id)
43 /* Just bump the counter. */
44 if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
45 /* Overflow of the counter. */
46 return EAGAIN;
48 ++mutex->__data.__count;
50 goto out;
52 else
54 /* We have to get the mutex. */
55 result = lll_mutex_timedlock (mutex->__data.__lock, abstime);
57 if (result != 0)
58 goto out;
60 /* Only locked once so far. */
61 mutex->__data.__count = 1;
63 break;
65 /* Error checking mutex. */
66 case PTHREAD_MUTEX_ERRORCHECK_NP:
67 /* Check whether we already hold the mutex. */
68 if (mutex->__data.__owner == id)
69 return EDEADLK;
71 /* FALLTHROUGH */
73 default:
74 /* Correct code cannot set any other type. */
75 case PTHREAD_MUTEX_TIMED_NP:
76 simple:
77 /* Normal mutex. */
78 result = lll_mutex_timedlock (mutex->__data.__lock, abstime);
79 break;
81 case PTHREAD_MUTEX_ADAPTIVE_NP:
82 if (! __is_smp)
83 goto simple;
85 if (lll_mutex_trylock (mutex->__data.__lock) != 0)
87 int cnt = 0;
88 int max_cnt = MIN (MAX_ADAPTIVE_COUNT,
89 mutex->__data.__spins * 2 + 10);
92 if (cnt++ >= max_cnt)
94 result = lll_mutex_timedlock (mutex->__data.__lock, abstime);
95 break;
98 #ifdef BUSY_WAIT_NOP
99 BUSY_WAIT_NOP;
100 #endif
102 while (lll_mutex_trylock (mutex->__data.__lock) != 0);
104 mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8;
106 break;
109 if (result == 0)
111 /* Record the ownership. */
112 mutex->__data.__owner = id;
113 ++mutex->__data.__nusers;
116 out:
117 return result;