[PATCH V3 5/8] scsi: Add template flag 'host_tagset'

Ming Lei
2018-02-27T10:07:47Z

From: Hannes Reinecke <hare@suse.com>

Add a host template flag 'host_tagset' to enable the use of a global
tagset for block-mq.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Arun Easi <arun.easi@cavium.com>
Cc: Omar Sandoval <osandov@fb.com>,
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
Cc: Christoph Hellwig <hch@lst.de>,
Cc: Don Brace <don.brace@microsemi.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Peter Rivera <peter.rivera@broadcom.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/scsi/scsi_lib.c | 2 ++
include/scsi/scsi_host.h | 3 +++
2 files changed, 5 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a86df9ca7d1c..8e6f118f1066 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2291,6 +2291,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
shost->tag_set.flags |=
BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
+ if (shost->hostt->host_tagset)
+ shost->tag_set.flags |= BLK_MQ_F_HOST_TAGS;
shost->tag_set.driver_data = shost;

return blk_mq_alloc_tag_set(&shost->tag_set);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 1a1df0d21ee3..1b35d9cb59b3 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -457,6 +457,9 @@ struct scsi_host_template {
*/
unsigned int max_host_blocked;

+ /* True if the host supports a host-wide tagspace */
+ unsigned host_tagset:1;
+
/*
* Default value for the blocking. If the queue is empty,
* host_blocked counts down in the request_fn until it restarts
--
2.9.5