[PATCH 2/2] scsi: Add template flag 'host_tagset'

[Hannes Reinecke <hare@suse.de>]

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

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/scsi_lib.c  | 2 ++
 include/scsi/scsi_host.h | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index ba22866..00036cb 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2193,6 +2193,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
 	shost->tag_set.cmd_size = cmd_size;
 	shost->tag_set.numa_node = NUMA_NO_NODE;
 	shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+	if (shost->hostt->host_tagset)
+		shost->tag_set.flags |= BLK_MQ_F_GLOBAL_TAGS;
 	shost->tag_set.flags |=
 		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
 	shost->tag_set.driver_data = shost;
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 3cd8c3b..dff3ec1 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -457,6 +457,11 @@ struct scsi_host_template {
 	unsigned no_async_abort:1;
 
 	/*
+	 * True if the host supports a host-wide tagspace
+	 */
+	unsigned host_tagset:1;
+
+	/*
 	 * Countdown for host blocking with no commands outstanding.
 	 */
 	unsigned int max_host_blocked;
-- 
1.8.5.6