Btrfs: handle kmalloc() failure in inode lookup ioctl

Return -ENOMEM if kmalloc() fails.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 874d36e..74d8913 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1211,6 +1211,9 @@
 		return -EPERM;
 
 	args = kmalloc(sizeof(*args), GFP_KERNEL);
+	if (!args)
+		return -ENOMEM;
+
 	if (copy_from_user(args, argp, sizeof(*args))) {
 		kfree(args);
 		return -EFAULT;