dm mpath: do not lock up a CPU with requeuing activity

When using the block layer in single queue mode, get_request()
returns ERR_PTR(-EAGAIN) if the queue is dying and the REQ_NOWAIT
flag has been passed to get_request(). Avoid that the kernel
reports soft lockup complaints in this case due to continuous
requeuing activity.

Fixes: 7083abbbf ("dm mpath: avoid that path removal can trigger an infinite loop")
Cc: [e-mail]
Signed-off-by: Bart Van Assche <[e-mail]>
Tested-by: Laurence Oberman <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-mpath.c

···
 		if (queue_dying) {
 			atomic_inc(&m->pg_init_in_progress);
 			activate_or_offline_path(pgpath);
-			return DM_MAPIO_REQUEUE;
 		}
 		return DM_MAPIO_DELAY_REQUEUE;
 	}