Merge branch 'queue' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target...

[karo-tx-linux.git] / include / linux / kref.h

diff --git a/include/linux/kref.h b/include/linux/kref.h
index 7419c02085d7207ba985d6f7e17c93ae21bebd36..484604d184be7380807868d9a12edc80e9064db3 100644 (file)
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -40,8 +40,11 @@ static inline void kref_init(struct kref *kref)
  */
 static inline void kref_get(struct kref *kref)
 {
-       WARN_ON(!atomic_read(&kref->refcount));
-       atomic_inc(&kref->refcount);
+       /* If refcount was 0 before incrementing then we have a race
+        * condition when this kref is freeing by some other thread right now.
+        * In this case one should use kref_get_unless_zero()
+        */
+       WARN_ON_ONCE(atomic_inc_return(&kref->refcount) < 2);
 }
 
 /**
@@ -133,7 +136,7 @@ static inline int kref_put_mutex(struct kref *kref,
                                 struct mutex *lock)
 {
        WARN_ON(release == NULL);
-        if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) {
+       if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) {
                mutex_lock(lock);
                if (unlikely(!atomic_dec_and_test(&kref->refcount))) {
                        mutex_unlock(lock);