#include "pthread_impl.h"
-int pthread_mutex_trylock(pthread_mutex_t *m)
+int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
{
- int tid;
- int own;
- pthread_t self;
+ int old, own;
+ int type = m->_m_type;
+ pthread_t self = __pthread_self();
+ int tid = self->tid;
- if (m->_m_type == PTHREAD_MUTEX_NORMAL)
- return (m->_m_lock || a_swap(&m->_m_lock, 1)) ? EBUSY : 0;
-
- self = pthread_self();
- tid = self->tid | 0x80000000;
-
- if (m->_m_type >= 4) {
- if (!self->robust_list.off)
- syscall(SYS_set_robust_list,
- &self->robust_list, 3*sizeof(long));
- self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
- self->robust_list.pending = &m->_m_next;
+ old = m->_m_lock;
+ own = old & 0x3fffffff;
+ if (own == tid) {
+ if ((type&8) && m->_m_count<0) {
+ old &= 0x40000000;
+ m->_m_count = 0;
+ goto success;
+ }
+ if ((type&3) == PTHREAD_MUTEX_RECURSIVE) {
+ if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
+ m->_m_count++;
+ return 0;
+ }
}
+ if (own == 0x3fffffff) return ENOTRECOVERABLE;
+ if (own || (old && !(type & 4))) return EBUSY;
- if (m->_m_lock == tid && (m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE) {
- if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
- m->_m_count++;
- return 0;
+ if (type & 128) {
+ if (!self->robust_list.off) {
+ self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
+ __syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
+ }
+ if (m->_m_waiters) tid |= 0x80000000;
+ self->robust_list.pending = &m->_m_next;
}
+ tid |= old & 0x40000000;
- own = m->_m_lock;
- if ((own && !(own & 0x40000000)) || a_cas(&m->_m_lock, own, tid)!=own)
+ if (a_cas(&m->_m_lock, old, tid) != old) {
+ self->robust_list.pending = 0;
+ if ((type&12)==12 & m->_m_waiters) return ENOTRECOVERABLE;
return EBUSY;
+ }
- m->_m_count = 1;
-
- if (m->_m_type < 4) return 0;
-
- if (m->_m_type >= 8) {
- m->_m_lock = 0;
- return ENOTRECOVERABLE;
+success:
+ if ((type&8) && m->_m_waiters) {
+ int priv = (type & 128) ^ 128;
+ __syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
+ self->robust_list.pending = 0;
+ return (type&4) ? ENOTRECOVERABLE : EBUSY;
}
- m->_m_next = self->robust_list.head;
+
+ volatile void *next = self->robust_list.head;
+ m->_m_next = next;
m->_m_prev = &self->robust_list.head;
- if (self->robust_list.head)
- self->robust_list.head[-1] = &m->_m_next;
+ if (next != &self->robust_list.head) *(volatile void *volatile *)
+ ((char *)next - sizeof(void *)) = &m->_m_next;
self->robust_list.head = &m->_m_next;
self->robust_list.pending = 0;
- if (own) {
- m->_m_type += 8;
+
+ if (old) {
+ m->_m_count = 0;
return EOWNERDEAD;
}
return 0;
}
+
+int __pthread_mutex_trylock(pthread_mutex_t *m)
+{
+ if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
+ return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
+ return __pthread_mutex_trylock_owner(m);
+}
+
+weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);