Add code comments to explain which call back function might be called
for the closure_queue(). This is an effort to make code to be more
understandable for readers.
Signed-off-by: NColy Li <colyli@suse.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>