blk-mq: Fix tagset reinit in the presence of cpu hot-unplug

[ Upstream commit 0067d4b ] In case cpu was unplugged, we need to make sure not to assume that the tags for that cpu are still allocated. so check for null tags when reinitializing a tagset. Reported-by: Yi Zhang <[email protected]> Signed-off-by: Sagi Grimberg <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
klaby · Dec 20, 2017 · d28046f · d28046f
1 parent 143d13d
commit d28046f
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
@@ -311,6 +311,9 @@ int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
 	for (i = 0; i < set->nr_hw_queues; i++) {
 		struct blk_mq_tags *tags = set->tags[i];
 
+		if (!tags)
+			continue;
+
 		for (j = 0; j < tags->nr_tags; j++) {
 			if (!tags->rqs[j])
 				continue;