diff options
| author | Ingo Molnar <mingo@elte.hu> | 2009-05-06 08:46:27 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-06 08:47:26 +0200 |
| commit | 3611dfb8eda847c1c8e1a052f57206f7fddc6a7c (patch) | |
| tree | 74b5d689be8bfca2ec0fe18961ccaf6953c21dba /kernel | |
| parent | perf_counter: tools: update the tools to support process and inherited counters (diff) | |
| parent | mutex: add atomic_dec_and_mutex_lock(), fix (diff) | |
| download | linux-3611dfb8eda847c1c8e1a052f57206f7fddc6a7c.tar.xz linux-3611dfb8eda847c1c8e1a052f57206f7fddc6a7c.zip | |
Merge branch 'core/locking' into perfcounters/core
Merge reason: we moved a mutex.h commit that originated from the
perfcounters tree into core/locking - but now merge
back that branch to solve a merge artifact and to
pick up cleanups of this commit that happened in
core/locking.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/mutex.c | 25 | ||||
| -rw-r--r-- | kernel/rtmutex.c | 8 |
2 files changed, 28 insertions, 5 deletions
diff --git a/kernel/mutex.c b/kernel/mutex.c index f415e80a9119..f788a5ace24b 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -471,5 +471,28 @@ int __sched mutex_trylock(struct mutex *lock) return ret; } - EXPORT_SYMBOL(mutex_trylock); + +/** + * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0 + * @cnt: the atomic which we are to dec + * @lock: the mutex to return holding if we dec to 0 + * + * return true and hold lock if we dec to 0, return false otherwise + */ +int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock) +{ + /* dec if we can't possibly hit 0 */ + if (atomic_add_unless(cnt, -1, 1)) + return 0; + /* we might hit 0, so take the lock */ + mutex_lock(lock); + if (!atomic_dec_and_test(cnt)) { + /* when we actually did the dec, we didn't hit 0 */ + mutex_unlock(lock); + return 0; + } + /* we hit 0, and we hold the lock */ + return 1; +} +EXPORT_SYMBOL(atomic_dec_and_mutex_lock); diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 69d9cb921ffa..013882e83497 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -864,9 +864,9 @@ int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock, EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible); /** - * rt_mutex_lock_interruptible_ktime - lock a rt_mutex interruptible - * the timeout structure is provided - * by the caller + * rt_mutex_timed_lock - lock a rt_mutex interruptible + * the timeout structure is provided + * by the caller * * @lock: the rt_mutex to be locked * @timeout: timeout structure or NULL (no timeout) @@ -913,7 +913,7 @@ void __sched rt_mutex_unlock(struct rt_mutex *lock) } EXPORT_SYMBOL_GPL(rt_mutex_unlock); -/*** +/** * rt_mutex_destroy - mark a mutex unusable * @lock: the mutex to be destroyed * |