Commit 1c23484c authored Aug 09, 2017 by Bart Van Assche Committed by Mike Snitzer Aug 28, 2017

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: 7083abbb ("dm mpath: avoid that path removal can trigger an infinite loop")
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

parent 60440789

drivers/md/dm-mpath.c

+0 −1

Original line number	Original line	Diff line number	Diff line
	@@ -504,7 +504,6 @@ static int multipath_clone_and_map(struct dm_target ti, struct request rq,
	if (queue_dying) {		if (queue_dying) {
	atomic_inc(&m->pg_init_in_progress);		atomic_inc(&m->pg_init_in_progress);
	activate_or_offline_path(pgpath);		activate_or_offline_path(pgpath);
	return DM_MAPIO_REQUEUE;
	}		}
	return DM_MAPIO_DELAY_REQUEUE;		return DM_MAPIO_DELAY_REQUEUE;
	}		}