minor locking optimizations

[musl] / src / thread / pthread_mutex_unlock.c

diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c
index 23e64ac..6c4d7f2 100644 (file)
--- a/src/thread/pthread_mutex_unlock.c
+++ b/src/thread/pthread_mutex_unlock.c
@@ -2,18 +2,29 @@
 
 int pthread_mutex_unlock(pthread_mutex_t *m)
 {
-       if (m->__type == PTHREAD_MUTEX_RECURSIVE) {
-               if (a_fetch_add(&m->__lock, -1)==1 && m->__waiters)
-                       __wake(&m->__lock, 1, 0);
-               return 0;
-       }
+       pthread_t self;
 
-       if (m->__type == PTHREAD_MUTEX_ERRORCHECK
-        && m->__owner != pthread_self())
-               return EPERM;
+       if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
+               if (!m->_m_lock)
+                       return EPERM;
+               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 >= 4) {
+                       self->robust_list.pending = &m->_m_next;
+                       *(void **)m->_m_prev = m->_m_next;
+                       if (m->_m_next) ((void **)m->_m_next)[-1] = m->_m_prev;
+                       a_store(&m->_m_lock, 0);
+                       self->robust_list.pending = 0;
+               } else {
+                       a_store(&m->_m_lock, 0);
+               }
+       } else {
+               a_store(&m->_m_lock, 0);
+       }
 
-       m->__owner = 0;
-       m->__lock = 0;
-       if (m->__waiters) __wake(&m->__lock, 1, 0);
+       if (m->_m_waiters) __wake(&m->_m_lock, 1, 0);
        return 0;
 }