[GIT PULL] mutex fix

[GIT PULL] mutex fix

[Ingo Molnar]

Linus,

Please pull the latest core-fixes-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-fixes-for-linus

 Thanks,

	Ingo

------------------>
Tony Breeds (1):
      mutex: Fix optimistic spinning vs. BKL


 kernel/mutex.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/kernel/mutex.c b/kernel/mutex.c
index 632f04c..4c0b7b3 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -172,6 +172,13 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 		struct thread_info *owner;
 
 		/*
+		 * If we own the BKL, then don't spin. The owner of
+		 * the mutex might be waiting on us to release the BKL.
+		 */
+		if (unlikely(current->lock_depth >= 0))
+			break;
+
+		/*
 		 * If there's an owner, wait for it to either
 		 * release the lock or go to sleep.
 		 */