Commits
Christophe JAILLET committed 772918524df
nbd: Fix error handling
'blk_mq_alloc_request()' returns an error pointer in case of error, not
NULL. So test it with IS_ERR.
Fixes: fd8383fd88a2 ("nbd: convert to blkmq")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jens Axboe <axboe@fb.com>