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Rewrite recursive mutex code

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This commit is contained in:
Justine Tunney 2022-09-10 09:14:40 -07:00
parent bae7367774
commit cfcf5918bc
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GPG key ID: BE714B4575D6E328
27 changed files with 164 additions and 257 deletions
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55
libc/intrin/pthread_mutex_trylock.c
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@ -33,36 +33,31 @@
* @raise ENOTRECOVERABLE if `mutex` is corrupted
*/
int pthread_mutex_trylock(pthread_mutex_t *mutex) {
int c, me, owner;
switch (mutex->type) {
case PTHREAD_MUTEX_NORMAL:
c = 0;
if (atomic_compare_exchange_strong_explicit(&mutex->lock, &c, 1,
memory_order_acquire,
memory_order_relaxed)) {
return 0;
} else {
return EBUSY;
}
case PTHREAD_MUTEX_RECURSIVE:
case PTHREAD_MUTEX_ERRORCHECK:
owner = 0;
me = gettid();
if (!atomic_compare_exchange_strong_explicit(&mutex->lock, &owner, me,
memory_order_acquire,
memory_order_relaxed)) {
if (owner == me) {
if (mutex->type == PTHREAD_MUTEX_ERRORCHECK) {
return EBUSY;
}
} else {
return EBUSY;
}
}
++mutex->reent;
int c, d, t;
if (mutex->type == PTHREAD_MUTEX_NORMAL) {
c = 0;
if (atomic_compare_exchange_strong_explicit(
&mutex->lock, &c, 1, memory_order_acquire, memory_order_relaxed)) {
return 0;
default:
assert(!"badlock");
return ENOTRECOVERABLE;
} else {
return EBUSY;
}
}
c = 0;
t = gettid();
d = 0x10100000 | t;
if (!atomic_compare_exchange_strong_explicit(
&mutex->lock, &c, d, memory_order_acquire, memory_order_relaxed)) {
if ((c & 0x000fffff) != t || mutex->type == PTHREAD_MUTEX_ERRORCHECK) {
return EBUSY;
}
if ((c & 0x0ff00000) == 0x0ff00000) {
return EAGAIN;
}
atomic_fetch_add_explicit(&mutex->lock, 0x00100000, memory_order_relaxed);
}
return 0;
}