blk-mq: make blk_abort_request() trigger timeout path (358f70da) · Commits · 戴 / test

With issue/complete and timeout paths now using the generation number and state based synchronization, blk_abort_request() is the only one which depends on REQ_ATOM_COMPLETE for arbitrating completion. There's no reason for blk_abort_request() to be a completely separate path. This patch makes blk_abort_request() piggyback on the timeout path instead of trying to terminate the request directly. This removes the last dependency on REQ_ATOM_COMPLETE in blk-mq. Note that this makes blk_abort_request() asynchronous - it initiates abortion but the actual termination will happen after a short while, even when the caller owns the request. AFAICS, SCSI and ATA should be fine with that and I think mtip32xx and dasd should be safe but not completely sure. It'd be great if people who know the drivers take a look. v2: - Add comment explaining the lack of synchronization around ->deadline update as requested by Bart. Signed-off-by:

Tejun Heo <tj@kernel.org> Cc: Asai Thambi SP <asamymuthupa@micron.com> Cc: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: Jan Hoeppner <hoeppner@linux.vnet.ibm.com> Cc: Bart Van Assche <Bart.VanAssche@wdc.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -820,7 +820,7 @@ struct blk_mq_timeout_data {
		unsigned int nr_expired;
		};

		void blk_mq_rq_timed_out(struct request *req, bool reserved)
		static void blk_mq_rq_timed_out(struct request *req, bool reserved)
		{
		const struct blk_mq_ops *ops = req->q->mq_ops;
		enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;

block/blk-mq.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -94,8 +94,6 @@ extern int blk_mq_sysfs_register(struct request_queue *q);
		extern void blk_mq_sysfs_unregister(struct request_queue *q);
		extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);

		extern void blk_mq_rq_timed_out(struct request *req, bool reserved);

		void blk_mq_release(struct request_queue *q);

		/**

block/blk-timeout.c

+9 −4

Original line number	Diff line number	Diff line
		@@ -156,12 +156,17 @@ void blk_timeout_work(struct work_struct *work)
		*/
		void blk_abort_request(struct request *req)
		{
		if (blk_mark_rq_complete(req))
		return;

		if (req->q->mq_ops) {
		blk_mq_rq_timed_out(req, false);
		/*
		* All we need to ensure is that timeout scan takes place
		* immediately and that scan sees the new timeout value.
		* No need for fancy synchronizations.
		*/
		req->deadline = jiffies;
		mod_timer(&req->q->timeout, 0);
		} else {
		if (blk_mark_rq_complete(req))
		return;
		blk_delete_timer(req);
		blk_rq_timed_out(req);
		}

Admin message