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authorAndrew Morton <akpm@linux-foundation.org>2009-04-29 18:59:58 -0400
committerIngo Molnar <mingo@elte.hu>2009-04-30 03:01:34 -0400
commita511e3f968c462a55ef58697257f5347c73d306e (patch)
tree7b331c694e0149f4f9e692eaec1726d28cedac8d /include/linux/mutex.h
parent23b94b967f118bef941369238f33c8140be46539 (diff)
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@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Eric Paris <eparis@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <200904292318.n3TNIsi6028340@imap1.linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/mutex.h')
-rw-r--r--include/linux/mutex.h24
1 files changed, 1 insertions, 23 deletions
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 93054fc3635c..878cab4f5fcc 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);
150 */ 150 */
151extern int mutex_trylock(struct mutex *lock); 151extern int mutex_trylock(struct mutex *lock);
152extern void mutex_unlock(struct mutex *lock); 152extern void mutex_unlock(struct mutex *lock);
153 153extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
154/**
155 * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
156 * @cnt: the atomic which we are to dec
157 * @lock: the mutex to return holding if we dec to 0
158 *
159 * return true and hold lock if we dec to 0, return false otherwise
160 */
161static inline int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
162{
163 /* dec if we can't possibly hit 0 */
164 if (atomic_add_unless(cnt, -1, 1))
165 return 0;
166 /* we might hit 0, so take the lock */
167 mutex_lock(lock);
168 if (!atomic_dec_and_test(cnt)) {
169 /* when we actually did the dec, we didn't hit 0 */
170 mutex_unlock(lock);
171 return 0;
172 }
173 /* we hit 0, and we hold the lock */
174 return 1;
175}
176 154
177#endif 155#endif