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Commit c934edad authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm table: allow upgrade from bio-based to specialized bio-based variant 



In practice this is really only meaningful in the context of the DM
multipath target (which uses dm_table_set_type() to set the type of
device DM should create via its "queue_mode" option).

So this change allows a DM multipath device with "queue_mode bio" to be
upgraded from DM_TYPE_BIO_BASED to DM_TYPE_NVME_BIO_BASED -- iff the
underlying device(s) are NVMe.

DM_TYPE_NVME_BIO_BASED is just a DM core implementation detail that
allows for NVMe-specific optimizations (e.g. use direct_make_request
instead of generic_make_request).  If in the future there is no benefit
or need to distinguish NVMe vs not: then it will be removed.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 8d47e659

drivers/md/dm-table.c

+5 −9
Original line number Diff line number Diff line
@@ -942,17 +942,12 @@ static int dm_table_determine_type(struct dm_table *t) 


	if (t->type != DM_TYPE_NONE) {

		/* target already set the table's type */

		if (t->type == DM_TYPE_BIO_BASED)

			return 0;

		else if (t->type == DM_TYPE_NVME_BIO_BASED) {

			if (!dm_table_does_not_support_partial_completion(t)) {

				DMERR("nvme bio-based is only possible with devices"

				      " that don't support partial completion");

				return -EINVAL;

			}

			/* Fallthru, also verify all devices are blk-mq */

		if (t->type == DM_TYPE_BIO_BASED) {

			/* possibly upgrade to a variant of bio-based */

			goto verify_bio_based;

		}

		BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED);

		BUG_ON(t->type == DM_TYPE_NVME_BIO_BASED);

		goto verify_rq_based;

	}
@@ -985,6 +980,7 @@ static int dm_table_determine_type(struct dm_table *t) 
	}



	if (bio_based) {

verify_bio_based:

		/* We must use this table as bio-based */

		t->type = DM_TYPE_BIO_BASED;

		if (dm_table_supports_dax(t) ||