On Wed, Aug 19, 2020 at 08:43:46AM +0100, John Garry wrote: > On 19/08/2020 01:00, Ming Lei wrote: > > On Tue, Aug 18, 2020 at 07:19:57PM +0100, John Garry wrote: > > > On 18/08/2020 13:03, John Garry wrote: > > > > Hi guys, > > > > > > > > JFYI, While doing some testing on v5.9-rc1, I stumbled across this: > > > > > > I bisected to here (hopefully without mistake): > > > > This one is a long-term problem, see the following discussion: > > > > https://lore.kernel.org/linux-block/1553492318-1810-1-git-send-email-jianchao.w.wang@xxxxxxxxxx/ > > > > > > ah, right. I vaguely remember this. Well, if we didn't have a reliable > reproducer before, we do now. OK, that is great, please try the following patch: diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 32d82e23b095..f18632c524e9 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -185,19 +185,19 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) { struct bt_iter_data *iter_data = data; struct blk_mq_hw_ctx *hctx = iter_data->hctx; - struct blk_mq_tags *tags = hctx->tags; + struct blk_mq_tags *tags = hctx->sched_tags ?: hctx->tags; bool reserved = iter_data->reserved; struct request *rq; if (!reserved) bitnr += tags->nr_reserved_tags; - rq = tags->rqs[bitnr]; + rq = tags->static_rqs[bitnr]; /* * We can hit rq == NULL here, because the tagging functions * test and set the bit before assigning ->rqs[]. */ - if (rq && rq->q == hctx->queue) + if (rq && rq->tag >= 0 && rq->q == hctx->queue) return iter_data->fn(hctx, rq, iter_data->data, reserved); return true; } @@ -406,7 +406,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn, return; queue_for_each_hw_ctx(q, hctx, i) { - struct blk_mq_tags *tags = hctx->tags; + struct blk_mq_tags *tags = hctx->sched_tags ?: hctx->tags; /* * If no software queues are currently mapped to this -- Ming
