kernfs: fix barrier usage in __kernfs_new_node()

commit 998267900cee901c5d1dfa029a6304d00acbc29f upstream.

smp_mb__before_atomic() can not be applied to atomic_set().  Remove the
barrier and rely on RELEASE synchronization.

Fixes: ba16b284 ("kernfs: add an API to get kernfs node from inode number")
Cc: stable@vger.kernel.org
Signed-off-by: NAndrea Parri <andrea.parri@amarulasolutions.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/kernfs/dir.c

@@ -650,11 +650,10 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
 	kn->id.generation = gen;
 
 	/*
-	 * set ino first. This barrier is paired with atomic_inc_not_zero in
+	 * set ino first. This RELEASE is paired with atomic_inc_not_zero in
 	 * kernfs_find_and_get_node_by_ino
 	 */
-	smp_mb__before_atomic();
-	atomic_set(&kn->count, 1);
+	atomic_set_release(&kn->count, 1);
 	atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
 	RB_CLEAR_NODE(&kn->rb);