cut out a syscall on thread creation in the case where guard size is 0

[musl] / src / thread / pthread_mutex_trylock.c

diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c
index 1e3817b..2dad7bb 100644 (file)
--- a/src/thread/pthread_mutex_trylock.c
+++ b/src/thread/pthread_mutex_trylock.c
@@ -2,27 +2,23 @@
 
 int pthread_mutex_trylock(pthread_mutex_t *m)
 {
-       if (m->__type == PTHREAD_MUTEX_RECURSIVE) {
-               pthread_t self = pthread_self();
-               if (m->__owner == self) {
-                       if ((unsigned)m->__lock >= INT_MAX) return EAGAIN;
-                       a_inc(&m->__lock);
-                       return 0;
-               }
-               if (a_fetch_add(&m->__lock, 1)) {
-                       if (a_fetch_add(&m->__lock, -1)==1 && m->__waiters)
-                               __wake(&m->__lock, 1, 0);
-                       return EBUSY;
-               }
-               m->__owner = self;
+       int tid;
+
+       if (m->_m_type == PTHREAD_MUTEX_NORMAL)
+               return -a_xchg(&m->_m_lock, 1) & EBUSY;
+
+       tid = pthread_self()->tid;
+
+       if (m->_m_owner == tid) {
+               if (m->_m_type != PTHREAD_MUTEX_RECURSIVE)
+                       return EDEADLK;
+               if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
+               m->_m_count++;
                return 0;
        }
 
-       if (a_xchg(&m->__lock, 1))
-               if (m->__type == PTHREAD_MUTEX_ERRORCHECK
-                && m->__owner == pthread_self()) return EDEADLK;
-               else return EBUSY;
-       if (m->__type == PTHREAD_MUTEX_ERRORCHECK)
-               m->__owner = pthread_self();
+       if (a_xchg(&m->_m_lock, 1)) return EBUSY;
+       m->_m_owner = tid;
+       m->_m_count = 1;
        return 0;
 }