>From scsi driver view, it is a bit troublesome to support both blk-mq
and non-blk-mq at the same time, especially when drivers need to support
multi hw-queue.
This patch introduces 'force_blk_mq' to scsi_host_template so that drivers
can provide blk-mq only support, so driver code can avoid the trouble
for supporting both.
Cc: Omar Sandoval <osandov@xxxxxx>,
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>,
Cc: James Bottomley <james.bottomley@xxxxxxxxxxxxxxxxxxxxx>,
Cc: Christoph Hellwig <hch@xxxxxx>,
Cc: Don Brace <don.brace@xxxxxxxxxxxxx>
Cc: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Laurence Oberman <loberman@xxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
drivers/scsi/hosts.c | 1 +
include/scsi/scsi_host.h | 3 +++
2 files changed, 4 insertions(+)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 57bf43e34863..10f04b089392 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -477,6 +477,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
shost->dma_boundary = 0xffffffff;
shost->use_blk_mq = scsi_use_blk_mq;
+ shost->use_blk_mq = scsi_use_blk_mq || !!shost->hostt->force_blk_mq;
device_initialize(&shost->shost_gendev);
dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 1a1df0d21ee3..6c6366f0bd15 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -452,6 +452,9 @@ struct scsi_host_template {
/* True if the controller does not support WRITE SAME */
unsigned no_write_same:1;
+ /* True if the low-level driver supports blk-mq only */
+ unsigned force_blk_mq:1;
+
/*
* Countdown for host blocking with no commands outstanding.
*/
--
2.9.5
