blk-mq: skip zero-queue maps in blk_mq_map_swqueue

From 7e849dd ("nvme-pci: don't share queue maps"), the mapping table won't be initialized actually if map->nr_queues is zero, so we can't use blk_mq_map_queue_type() to retrieve hctx any more. This way still may cause broken mapping, fix it by skipping zero-queues maps in blk_mq_map_swqueue(). Cc: Jeff Moyer <[email protected]> Cc: Mike Snitzer <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Ming Lei <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
jbg · Dec 17, 2018 · e5edd5f · e5edd5f
1 parent 1336981
commit e5edd5f
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/block/blk-mq.c b/block/blk-mq.c
@@ -2438,6 +2438,9 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 
 		ctx = per_cpu_ptr(q->queue_ctx, i);
 		for (j = 0; j < set->nr_maps; j++) {
+			if (!set->map[j].nr_queues)
+				continue;
+
 			hctx = blk_mq_map_queue_type(q, j, i);
 
 			/*