dm rq: fix the starting and stopping of blk-mq queues (7d9595d8) · Commits · 戴 / test

drivers/md/dm-rq.c

+19 −1

Original line number	Diff line number	Diff line
		@@ -78,6 +78,7 @@ void dm_start_queue(struct request_queue *q)
		if (!q->mq_ops)
		dm_old_start_queue(q);
		else {
		queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, q);
		blk_mq_start_stopped_hw_queues(q, true);
		blk_mq_kick_requeue_list(q);
		}
		@@ -101,9 +102,15 @@ void dm_stop_queue(struct request_queue *q)
		{
		if (!q->mq_ops)
		dm_old_stop_queue(q);
		else
		else {
		spin_lock_irq(q->queue_lock);
		queue_flag_set(QUEUE_FLAG_STOPPED, q);
		spin_unlock_irq(q->queue_lock);

		blk_mq_cancel_requeue_work(q);
		blk_mq_stop_hw_queues(q);
		}
		}

		static struct dm_rq_target_io alloc_old_rq_tio(struct mapped_device md,
		gfp_t gfp_mask)
		@@ -864,6 +871,17 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
		dm_put_live_table(md, srcu_idx);
		}

		/*
		* On suspend dm_stop_queue() handles stopping the blk-mq
		* request_queue BUT: even though the hw_queues are marked
		* BLK_MQ_S_STOPPED at that point there is still a race that
		* is allowing block/blk-mq.c to call ->queue_rq against a
		* hctx that it really shouldn't. The following check guards
		* against this rarity (albeit _not_ race-free).
		*/
		if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
		return BLK_MQ_RQ_QUEUE_BUSY;

		if (ti->type->busy && ti->type->busy(ti))
		return BLK_MQ_RQ_QUEUE_BUSY;