Don't forget to zero locked_free_nr, it's not a disaster but makes it
attempting to flush it with extra locking when there is nothing in the
list. Also, don't traverse a potentially long list freeing requests
under spinlock, splice the list and do it afterwards.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>