generic-library/bionic
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Merge "POSIX says pthread_mutex_trylock returns EBUSY, not EDEADLK."

Browse Source
This commit is contained in:
Elliott Hughes 2014-10-27 17:38:33 +00:00 committed by Gerrit Code Review
commit 7f164f6052
1 changed files with 12 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
libc/bionic/pthread_mutex.cpp
View File

@ -578,15 +578,12 @@ int pthread_mutex_unlock(pthread_mutex_t* mutex) {
}
int pthread_mutex_trylock(pthread_mutex_t* mutex) {
int mvalue, mtype, tid, shared;
int mvalue = mutex->value;
int mtype = (mvalue & MUTEX_TYPE_MASK);
int shared = (mvalue & MUTEX_SHARED_MASK);
mvalue = mutex->value;
mtype = (mvalue & MUTEX_TYPE_MASK);
shared = (mvalue & MUTEX_SHARED_MASK);
/* Handle common case first */
if ( __predict_true(mtype == MUTEX_TYPE_BITS_NORMAL) )
{
// Handle common case first.
if (__predict_true(mtype == MUTEX_TYPE_BITS_NORMAL)) {
if (__bionic_cmpxchg(shared|MUTEX_STATE_BITS_UNLOCKED,
shared|MUTEX_STATE_BITS_LOCKED_UNCONTENDED,
&mutex->value) == 0) {
@ -597,10 +594,14 @@ int pthread_mutex_trylock(pthread_mutex_t* mutex) {
return EBUSY;
}
/* Do we already own this recursive or error-check mutex ? */
tid = __get_thread()->tid;
if ( tid == MUTEX_OWNER_FROM_BITS(mvalue) )
// Do we already own this recursive or error-check mutex?
pid_t tid = __get_thread()->tid;
if (tid == MUTEX_OWNER_FROM_BITS(mvalue)) {
if (mtype == MUTEX_TYPE_BITS_ERRORCHECK) {
return EBUSY;
}
return _recursive_increment(mutex, mvalue, mtype);
}
/* Same as pthread_mutex_lock, except that we don't want to wait, and
* the only operation that can succeed is a single cmpxchg to acquire the