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authorRich Felker <dalias@aerifal.cx>2011-10-03 00:09:08 -0400
committerRich Felker <dalias@aerifal.cx>2011-10-03 00:09:08 -0400
commit7fe58d3511387ab6c57909f6e4baef58acd6bd56 (patch)
treec41921898477f2269c44b68b1befce6e6660cc0b /src/thread
parentb3b00d11e87926b553429d341b020a8a070e4ea1 (diff)
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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.
Diffstat (limited to 'src/thread')
-rw-r--r--src/thread/pthread_mutex_trylock.c2
-rw-r--r--src/thread/pthread_mutex_unlock.c4
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;