linux-kernel - [tip:core/locking] mutex: add atomic_dec_and_mutex

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Date:	Thu, 30 Apr 2009 07:03:29 GMT
From:	tip-bot for Andrew Morton <akpm@...ux-foundation.org>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, paulus@...ba.org, hpa@...or.com,
	mingo@...hat.com, a.p.zijlstra@...llo.nl, eparis@...hat.com,
	viro@...iv.linux.org.uk, akpm@...ux-foundation.org, hch@....de,
	tglx@...utronix.de, mingo@...e.hu
Subject: [tip:core/locking] mutex: add atomic_dec_and_mutex_lock(), fix

Commit-ID:  a511e3f968c462a55ef58697257f5347c73d306e
Gitweb:     http://git.kernel.org/tip/a511e3f968c462a55ef58697257f5347c73d306e
Author:     Andrew Morton <akpm@...ux-foundation.org>
AuthorDate: Wed, 29 Apr 2009 15:59:58 -0700
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Thu, 30 Apr 2009 09:01:34 +0200

mutex: add atomic_dec_and_mutex_lock(), fix

include/linux/mutex.h:136: warning: 'mutex_lock' declared inline after being called
 include/linux/mutex.h:136: warning: previous declaration of 'mutex_lock' was here

uninline it.

[ Impact: clean up and uninline, address compiler warning ]

Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: Christoph Hellwig <hch@....de>
Cc: Eric Paris <eparis@...hat.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
LKML-Reference: <200904292318.n3TNIsi6028340@...p1.linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@...e.hu>


---
 include/linux/mutex.h |   24 +-----------------------
 kernel/mutex.c        |   25 ++++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 93054fc..878cab4 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -150,28 +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);
-
-/**
- * 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
- */
-static inline 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;
-}
+extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
 
 #endif
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);
--
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