elf.h: add ELFCOMPRESS_ZSTD

[musl] / src / thread / pthread_mutex_unlock.c

diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c
index 67aa7ba..b66423e 100644 (file)
--- a/src/thread/pthread_mutex_unlock.c
+++ b/src/thread/pthread_mutex_unlock.c
@@ -1,24 +1,52 @@
 #include "pthread_impl.h"
 
-int pthread_mutex_unlock(pthread_mutex_t *m)
+int __pthread_mutex_unlock(pthread_mutex_t *m)
 {
        pthread_t self;
+       int waiters = m->_m_waiters;
+       int cont;
+       int type = m->_m_type & 15;
+       int priv = (m->_m_type & 128) ^ 128;
+       int new = 0;
+       int old;
 
-       if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
+       if (type != PTHREAD_MUTEX_NORMAL) {
                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) {
+               old = m->_m_lock;
+               int own = old & 0x3fffffff;
+               if (own != self->tid)
+                       return EPERM;
+               if ((type&3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count)
+                       return m->_m_count--, 0;
+               if ((type&4) && (old&0x40000000))
+                       new = 0x7fffffff;
+               if (!priv) {
                        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;
+                       __vm_lock();
                }
+               volatile void *prev = m->_m_prev;
+               volatile void *next = m->_m_next;
+               *(volatile void *volatile *)prev = next;
+               if (next != &self->robust_list.head) *(volatile void *volatile *)
+                       ((char *)next - sizeof(void *)) = prev;
        }
-
-       m->_m_lock = 0;
-       if (m->_m_waiters) __wake(&m->_m_lock, 1, 0);
-       if (m->_m_type >= 4) self->robust_list.pending = 0;
+       if (type&8) {
+               if (old<0 || a_cas(&m->_m_lock, old, new)!=old) {
+                       if (new) a_store(&m->_m_waiters, -1);
+                       __syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
+               }
+               cont = 0;
+               waiters = 0;
+       } else {
+               cont = a_swap(&m->_m_lock, new);
+       }
+       if (type != PTHREAD_MUTEX_NORMAL && !priv) {
+               self->robust_list.pending = 0;
+               __vm_unlock();
+       }
+       if (waiters || cont<0)
+               __wake(&m->_m_lock, 1, priv);
        return 0;
 }
+
+weak_alias(__pthread_mutex_unlock, pthread_mutex_unlock);