/* 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