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Commit 358f70da authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blk-mq: make blk_abort_request() trigger timeout path 



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: default avatarTejun 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: default avatarJens Axboe <axboe@kernel.dk>
parent 67818d25

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);

	}