Btrfs: cleanup fs/btrfs/super.c::btrfs_control_ioctl()

- Remove the unused local variable 'len';
- Check return value of kmalloc().

Signed-off-by: Wang Cong <wangcong@zeuux.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 92c9b54..795b624 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -583,17 +583,18 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
        struct btrfs_ioctl_vol_args *vol;
        struct btrfs_fs_devices *fs_devices;
        int ret = -ENOTTY;
-       int len;
 
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
 
        vol = kmalloc(sizeof(*vol), GFP_KERNEL);
+       if (!vol)
+               return -ENOMEM;
+
        if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {
                ret = -EFAULT;
                goto out;
        }
-       len = strnlen(vol->name, BTRFS_PATH_NAME_MAX);
 
        switch (cmd) {
        case BTRFS_IOC_SCAN_DEV: