@@ -441,6 +442,8 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q, if (!hctx->sched_tags) return -ENOMEM;+ set->sched_tags[hctx_idx] = hctx->sched_tags;+ ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests); if (ret) blk_mq_sched_free_tags(set, hctx, hctx_idx);Will this work as expected if a tag set is shared across multiple request queues?
Probably not.
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index c81b40e..c290de0 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -322,6 +322,22 @@ int blk_mq_tagset_iter(struct blk_mq_tag_set *set, void *data, } }+ for (i = 0; i < set->nr_hw_queues; i++) {+ struct blk_mq_tags *sched_tags = set->sched_tags[i]; + + if (!sched_tags) + continue; + + for (j = 0; j < sched_tags->nr_tags; j++) { + if (!sched_tags->static_rqs[j]) + continue; + + ret = fn(data, sched_tags->static_rqs[j]); + if (ret) + goto out; + } + }If both a scheduler tag and a driver tag have been assigned to a request, can this cause blk_mq_tagset_iter() to call fn() twice for the same request?
It will, its not a big issue for reinit functionality, but it might if used for something else. I don't think its a good idea to go down this route.
