kref: Implement kref_put in terms of kref_sub

Less lines of code is better.

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/kref.h b/include/linux/kref.h
index 1cbae9f..fa9907a 100644 (file)
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -44,57 +44,49 @@ static inline void kref_get(struct kref *kref)
 }
 
 /**
- * kref_put - decrement refcount for object.
+ * kref_sub - subtract a number of refcounts for object.
  * @kref: object.
+ * @count: Number of recounts to subtract.
  * @release: pointer to the function that will clean up the object when the
  *          last reference to the object is released.
  *          This pointer is required, and it is not acceptable to pass kfree
  *          in as this function.
  *
- * Decrement the refcount, and if 0, call release().
+ * Subtract @count from the refcount, and if 0, call release().
  * Return 1 if the object was removed, otherwise return 0.  Beware, if this
  * function returns 0, you still can not count on the kref from remaining in
  * memory.  Only use the return value if you want to see if the kref is now
  * gone, not present.
  */
-static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref))
+static inline int kref_sub(struct kref *kref, unsigned int count,
+            void (*release)(struct kref *kref))
 {
        WARN_ON(release == NULL);
        WARN_ON(release == (void (*)(struct kref *))kfree);
 
-       if (atomic_dec_and_test(&kref->refcount)) {
+       if (atomic_sub_and_test((int) count, &kref->refcount)) {
                release(kref);
                return 1;
        }
        return 0;
 }
 
-
 /**
- * kref_sub - subtract a number of refcounts for object.
+ * kref_put - decrement refcount for object.
  * @kref: object.
- * @count: Number of recounts to subtract.
  * @release: pointer to the function that will clean up the object when the
  *          last reference to the object is released.
  *          This pointer is required, and it is not acceptable to pass kfree
  *          in as this function.
  *
- * Subtract @count from the refcount, and if 0, call release().
+ * Decrement the refcount, and if 0, call release().
  * Return 1 if the object was removed, otherwise return 0.  Beware, if this
  * function returns 0, you still can not count on the kref from remaining in
  * memory.  Only use the return value if you want to see if the kref is now
  * gone, not present.
  */
-static inline int kref_sub(struct kref *kref, unsigned int count,
-            void (*release)(struct kref *kref))
+static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref))
 {
-       WARN_ON(release == NULL);
-       WARN_ON(release == (void (*)(struct kref *))kfree);
-
-       if (atomic_sub_and_test((int) count, &kref->refcount)) {
-               release(kref);
-               return 1;
-       }
-       return 0;
+       return kref_sub(kref, 1, release);
 }
 #endif /* _KREF_H_ */