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authorUlrich Drepper <drepper@redhat.com>2005-12-27 01:04:06 +0000
committerUlrich Drepper <drepper@redhat.com>2005-12-27 01:04:06 +0000
commit1bcfb5a5eb1c25b64a329c1edf6bcfb440cdbc93 (patch)
treeefa74fd1d0c2f6fccda616328a7b432ffdc6ba92 /nptl/pthread_mutex_trylock.c
parent* stdlib/Makefile ($(objpfx)isomac.out): Move -I.. to the end so (diff)
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* Versions.def: Add GLIBC_2.4 for libpthread.cvs/fedora-glibc-20051227T1426
Diffstat (limited to 'nptl/pthread_mutex_trylock.c')
-rw-r--r--nptl/pthread_mutex_trylock.c88
1 files changed, 81 insertions, 7 deletions
diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c
index 8213f90da9..ae73ecc39b 100644
--- a/nptl/pthread_mutex_trylock.c
+++ b/nptl/pthread_mutex_trylock.c
@@ -17,7 +17,9 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
+#include <assert.h>
#include <errno.h>
+#include <stdlib.h>
#include "pthreadP.h"
#include <lowlevellock.h>
@@ -26,13 +28,12 @@ int
__pthread_mutex_trylock (mutex)
pthread_mutex_t *mutex;
{
- pid_t id;
+ pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP))
{
/* Recursive mutex. */
case PTHREAD_MUTEX_RECURSIVE_NP:
- id = THREAD_GETMEM (THREAD_SELF, tid);
/* Check whether we already hold the mutex. */
if (mutex->__data.__owner == id)
{
@@ -56,20 +57,93 @@ __pthread_mutex_trylock (mutex)
break;
case PTHREAD_MUTEX_ERRORCHECK_NP:
- /* Error checking mutex. We do not check for deadlocks. */
+ /* Check whether we already hold the mutex. */
+ if (__builtin_expect (mutex->__data.__owner == id, 0))
+ return EDEADLK;
+
+ /* FALLTHROUGH */
+
case PTHREAD_MUTEX_TIMED_NP:
case PTHREAD_MUTEX_ADAPTIVE_NP:
/* Normal mutex. */
- if (lll_mutex_trylock (mutex->__data.__lock) == 0)
+ if (lll_mutex_trylock (mutex->__data.__lock) != 0)
+ break;
+
+ /* Record the ownership. */
+ mutex->__data.__owner = id;
+ ++mutex->__data.__nusers;
+
+ return 0;
+
+
+ case PTHREAD_MUTEX_ROBUST_PRIVATE_RECURSIVE_NP:
+ /* Check whether we already hold the mutex. */
+ if (abs (mutex->__data.__owner) == id)
{
- /* Record the ownership. */
- mutex->__data.__owner = THREAD_GETMEM (THREAD_SELF, tid);
- ++mutex->__data.__nusers;
+ /* Just bump the counter. */
+ if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
+ /* Overflow of the counter. */
+ return EAGAIN;
+
+ ++mutex->__data.__count;
return 0;
}
+
+ /* We have to get the mutex. */
+ if (lll_mutex_trylock (mutex->__data.__lock) == 0)
+ {
+ mutex->__data.__count = 1;
+
+ goto robust;
+ }
+
break;
+ case PTHREAD_MUTEX_ROBUST_PRIVATE_ERRORCHECK_NP:
+ /* Check whether we already hold the mutex. */
+ if (__builtin_expect (abs (mutex->__data.__owner) == id, 0))
+ return EDEADLK;
+
+ /* FALLTHROUGH */
+
+ case PTHREAD_MUTEX_ROBUST_PRIVATE_NP:
+ case PTHREAD_MUTEX_ROBUST_PRIVATE_ADAPTIVE_NP:
+ if (lll_mutex_trylock (mutex->__data.__lock) != 0)
+ break;
+
+ robust:
+ if (__builtin_expect (mutex->__data.__owner
+ == PTHREAD_MUTEX_NOTRECOVERABLE, 0))
+ {
+ /* This mutex is now not recoverable. */
+ mutex->__data.__count = 0;
+ lll_mutex_unlock (mutex->__data.__lock);
+ return ENOTRECOVERABLE;
+ }
+
+ /* This mutex is either healthy or we can try to recover it. */
+ assert (mutex->__data.__owner == 0
+ || mutex->__data.__owner == PTHREAD_MUTEX_OWNERDEAD);
+
+ /* Record the ownership. */
+ int retval = 0;
+ if (__builtin_expect (mutex->__data.__owner
+ == PTHREAD_MUTEX_OWNERDEAD, 0))
+ {
+ retval = EOWNERDEAD;
+ /* We signal ownership of a not yet recovered robust
+ mutex by storing the negative thread ID. */
+ id = -id;
+ }
+
+ ENQUEUE_MUTEX (mutex);
+
+ mutex->__data.__owner = id;
+ ++mutex->__data.__nusers;
+
+ return retval
+;
default:
/* Correct code cannot set any other type. */
return EINVAL;