blob: e85151797341b8d6596970f23c5cf906f0164a1d (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
#include "pthread_impl.h"
int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
{
int old, own;
int type = m->_m_type & 15;
pthread_t self = __pthread_self();
int tid = self->tid;
if (!self->robust_list.off) {
__syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
self->robust_list.head = &self->robust_list.head;
self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
}
old = m->_m_lock;
own = old & 0x7fffffff;
if (own == tid && (type&3) == PTHREAD_MUTEX_RECURSIVE) {
if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
m->_m_count++;
return 0;
}
if (own == 0x40000000) return ENOTRECOVERABLE;
if (m->_m_type & 128) {
if (m->_m_waiters) tid |= 0x80000000;
self->robust_list.pending = &m->_m_next;
}
if ((own && (!(own & 0x40000000) || !(type & 4)))
|| a_cas(&m->_m_lock, old, tid) != old) {
self->robust_list.pending = 0;
return EBUSY;
}
volatile void *next = self->robust_list.head;
m->_m_next = next;
m->_m_prev = &self->robust_list.head;
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_count = 0;
m->_m_type |= 8;
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);
}
|
