Messages in this thread Patch in this message | | | Date | Thu, 11 Jun 2009 00:12:24 +0200 | From | Ingo Molnar <> | Subject | [GIT PULL] core/locking for v2.6.31 |
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Linus,
Please pull the latest locking-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git locking-for-linus
Thanks,
Ingo
------------------> Andrew Morton (1): mutex: add atomic_dec_and_mutex_lock(), fix
Benjamin Herrenschmidt (1): spinlock: Add missing __raw_spin_lock_flags() stub for UP
Eric Paris (1): mutex: add atomic_dec_and_mutex_lock()
Luis Henriques (1): locking, rtmutex.c: Documentation cleanup
include/linux/mutex.h | 1 + include/linux/spinlock_up.h | 1 + kernel/mutex.c | 25 ++++++++++++++++++++++++- kernel/rtmutex.c | 8 ++++---- 4 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 3069ec7..878cab4 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -150,5 +150,6 @@ extern int __must_check mutex_lock_killable(struct mutex *lock); */ extern int mutex_trylock(struct mutex *lock); extern void mutex_unlock(struct mutex *lock); +extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); #endif diff --git a/include/linux/spinlock_up.h b/include/linux/spinlock_up.h index 938234c..d4841ed 100644 --- a/include/linux/spinlock_up.h +++ b/include/linux/spinlock_up.h @@ -60,6 +60,7 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock) #define __raw_spin_is_locked(lock) ((void)(lock), 0) /* for sched.c and kernel_lock.c: */ # define __raw_spin_lock(lock) do { (void)(lock); } while (0) +# define __raw_spin_lock_flags(lock, flags) do { (void)(lock); } while (0) # define __raw_spin_unlock(lock) do { (void)(lock); } while (0) # define __raw_spin_trylock(lock) ({ (void)(lock); 1; }) #endif /* DEBUG_SPINLOCK */ diff --git a/kernel/mutex.c b/kernel/mutex.c index 507cf2b..e2d25e9 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 69d9cb9..013882e 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 *
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