From 7fe58d3511387ab6c57909f6e4baef58acd6bd56 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 3 Oct 2011 00:09:08 -0400 Subject: use count=0 instead of 1 for recursive mutex with only one lock reference this simplifies the code paths slightly, but perhaps what's nicer is that it makes recursive mutexes fully reentrant, i.e. locking and unlocking from a signal handler works even if the interrupted code was in the middle of locking or unlocking. --- src/thread/pthread_mutex_trylock.c | 2 -- src/thread/pthread_mutex_unlock.c | 4 ++-- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c index 4a424bc9..fb277970 100644 --- a/src/thread/pthread_mutex_trylock.c +++ b/src/thread/pthread_mutex_trylock.c @@ -30,8 +30,6 @@ int pthread_mutex_trylock(pthread_mutex_t *m) if ((own && !(own & 0x40000000)) || a_cas(&m->_m_lock, old, tid)!=old) return EBUSY; - m->_m_count = 1; - if (m->_m_type < 4) return 0; if (m->_m_type >= 8) { diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c index 0f4a5e6c..05baec18 100644 --- a/src/thread/pthread_mutex_unlock.c +++ b/src/thread/pthread_mutex_unlock.c @@ -12,8 +12,8 @@ int pthread_mutex_unlock(pthread_mutex_t *m) self = __pthread_self(); if ((m->_m_lock&0x1fffffff) != self->tid) return EPERM; - if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && --m->_m_count) - return 0; + if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count) + return m->_m_count--, 0; if (m->_m_type >= 4) { self->robust_list.pending = &m->_m_next; *(void **)m->_m_prev = m->_m_next; -- cgit v1.2.1