block/ndb: add WQ_UNBOUND to the knbd-recv workqueue

Add WQ_UNBOUND to the knbd-recv workqueue so we're not bound
to a single CPU that is selected at device creation time.
Signed-off-by: Dan Melnic <dmm@fb.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/nbd.c

@@ -2106,7 +2106,8 @@ static int __init nbd_init(void)
 	if (nbds_max > 1UL << (MINORBITS - part_shift))
 		return -EINVAL;
 	recv_workqueue = alloc_workqueue("knbd-recv",
-					 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
+					 WQ_MEM_RECLAIM | WQ_HIGHPRI |
+					 WQ_UNBOUND, 0);
 	if (!recv_workqueue)
 		return -ENOMEM;