diff options
Diffstat (limited to 'nptl/pthread_mutex_trylock.c')
-rw-r--r-- | nptl/pthread_mutex_trylock.c | 88 |
1 files changed, 81 insertions, 7 deletions
diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c index 8213f90..ae73ecc 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; |