When it was introduced in commit 
f094ac32aba3 ("Btrfs: fix NULL pointer
after aborting a transaction"), it was not used.
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
 {
        struct btrfs_fs_info *fs_info = trans->fs_info;
        struct btrfs_transaction *cur_trans = trans->transaction;
-       DEFINE_WAIT(wait);
 
        WARN_ON(refcount_read(&trans->use_count) > 1);