| /* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include "pthreadP.h" |
| #include <lowlevellock.h> |
| |
| |
| #ifndef LLL_MUTEX_LOCK |
| # define LLL_MUTEX_LOCK(mutex) lll_mutex_lock (mutex) |
| # define LLL_MUTEX_TRYLOCK(mutex) lll_mutex_trylock (mutex) |
| #endif |
| |
| |
| int |
| __pthread_mutex_lock (mutex) |
| pthread_mutex_t *mutex; |
| { |
| assert (sizeof (mutex->__size) >= sizeof (mutex->__data)); |
| |
| pid_t id = THREAD_GETMEM (THREAD_SELF, tid); |
| |
| switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP)) |
| { |
| /* Recursive mutex. */ |
| case PTHREAD_MUTEX_RECURSIVE_NP: |
| /* Check whether we already hold the mutex. */ |
| if (mutex->__data.__owner == id) |
| { |
| /* Just bump the counter. */ |
| if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) |
| /* Overflow of the counter. */ |
| return EAGAIN; |
| |
| ++mutex->__data.__count; |
| |
| return 0; |
| } |
| |
| /* We have to get the mutex. */ |
| LLL_MUTEX_LOCK (mutex->__data.__lock); |
| |
| mutex->__data.__count = 1; |
| break; |
| |
| /* Error checking mutex. */ |
| case PTHREAD_MUTEX_ERRORCHECK_NP: |
| /* Check whether we already hold the mutex. */ |
| if (mutex->__data.__owner == id) |
| return EDEADLK; |
| |
| /* FALLTHROUGH */ |
| |
| default: |
| /* Correct code cannot set any other type. */ |
| case PTHREAD_MUTEX_TIMED_NP: |
| simple: |
| /* Normal mutex. */ |
| LLL_MUTEX_LOCK (mutex->__data.__lock); |
| break; |
| |
| case PTHREAD_MUTEX_ADAPTIVE_NP: |
| if (! __is_smp) |
| goto simple; |
| |
| if (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0) |
| { |
| int cnt = 0; |
| int max_cnt = MIN (MAX_ADAPTIVE_COUNT, |
| mutex->__data.__spins * 2 + 10); |
| do |
| { |
| if (cnt++ >= max_cnt) |
| { |
| LLL_MUTEX_LOCK (mutex->__data.__lock); |
| break; |
| } |
| |
| #ifdef BUSY_WAIT_NOP |
| BUSY_WAIT_NOP; |
| #endif |
| } |
| while (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0); |
| |
| mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8; |
| } |
| break; |
| } |
| |
| /* Record the ownership. */ |
| assert (mutex->__data.__owner == 0); |
| mutex->__data.__owner = id; |
| #ifndef NO_INCR |
| ++mutex->__data.__nusers; |
| #endif |
| |
| return 0; |
| } |
| #ifndef __pthread_mutex_lock |
| strong_alias (__pthread_mutex_lock, pthread_mutex_lock) |
| strong_alias (__pthread_mutex_lock, __pthread_mutex_lock_internal) |
| #endif |