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Commit e262f347 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm stats: add support for request-based DM devices 



This makes it possible to use dm stats with DM multipath.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent dfcfac3e

drivers/md/dm-stats.c

+0 −5
Original line number Diff line number Diff line
@@ -1155,11 +1155,6 @@ int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv, 
{

	int r;



	if (dm_request_based(md)) {

		DMWARN("Statistics are only supported for bio-based devices");

		return -EOPNOTSUPP;

	}



	/* All messages here must start with '@' */

	if (!strcasecmp(argv[0], "@stats_create"))

		r = message_stats_create(md, argc, argv, result, maxlen);

drivers/md/dm.c

+26 −0
Original line number Diff line number Diff line
@@ -86,6 +86,9 @@ struct dm_rq_target_io { 
	struct kthread_work work;

	int error;

	union map_info info;

	struct dm_stats_aux stats_aux;

	unsigned long duration_jiffies;

	unsigned n_sectors;

};



/*
@@ -995,6 +998,17 @@ static struct dm_rq_target_io *tio_from_request(struct request *rq) 
	return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special);

}



static void rq_end_stats(struct mapped_device *md, struct request *orig)

{

	if (unlikely(dm_stats_used(&md->stats))) {

		struct dm_rq_target_io *tio = tio_from_request(orig);

		tio->duration_jiffies = jiffies - tio->duration_jiffies;

		dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig),

				    tio->n_sectors, true, tio->duration_jiffies,

				    &tio->stats_aux);

	}

}



/*

 * Don't touch any member of the md after calling this function because

 * the md may be freed in dm_put() at the end of this function.
@@ -1078,6 +1092,7 @@ static void dm_end_request(struct request *clone, int error) 
	}



	free_rq_clone(clone);

	rq_end_stats(md, rq);

	if (!rq->q->mq_ops)

		blk_end_request_all(rq, error);

	else
@@ -1120,6 +1135,7 @@ static void dm_requeue_original_request(struct mapped_device *md, 


	dm_unprep_request(rq);



	rq_end_stats(md, rq);

	if (!rq->q->mq_ops)

		old_requeue_request(rq);

	else {
@@ -1211,6 +1227,7 @@ static void dm_softirq_done(struct request *rq) 
	int rw;



	if (!clone) {

		rq_end_stats(tio->md, rq);

		rw = rq_data_dir(rq);

		if (!rq->q->mq_ops) {

			blk_end_request_all(rq, tio->error);
@@ -1943,6 +1960,14 @@ static void dm_start_request(struct mapped_device *md, struct request *orig) 
		md->last_rq_start_time = ktime_get();

	}



	if (unlikely(dm_stats_used(&md->stats))) {

		struct dm_rq_target_io *tio = tio_from_request(orig);

		tio->duration_jiffies = jiffies;

		tio->n_sectors = blk_rq_sectors(orig);

		dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig),

				    tio->n_sectors, false, 0, &tio->stats_aux);

	}



	/*

	 * Hold the md reference here for the in-flight I/O.

	 * We can't rely on the reference count by device opener,
@@ -2689,6 +2714,7 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, 
		/* Direct call is fine since .queue_rq allows allocations */

		if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {

			/* Undo dm_start_request() before requeuing */

			rq_end_stats(md, rq);

			rq_completed(md, rq_data_dir(rq), false);

			return BLK_MQ_RQ_QUEUE_BUSY;

		}