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

Hannes Reinecke
2019-11-26T09:14:32Z

From: Hannes Reinecke <hare@suse.com>

Add a host template flag 'host_tagset' so hostwide tagset can be
shared on multiple reply queues after the SCSI device's reply queue
is converted to blk-mq hw queue.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: John Garry <john.garry@huawei.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 2563b061f56b..d7ad7b99bc05 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1899,6 +1899,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
shost->tag_set.flags = BLK_MQ_F_SHOULD_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_TAG_HCTX_SHARED;
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 f577647bf5f2..4fd0af0883dd 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -429,6 +429,9 @@ struct scsi_host_template {
/* True if the low-level driver supports blk-mq only */
unsigned force_blk_mq:1;

+ /* True if the host uses host-wide tagspace */
+ unsigned host_tagset:1;
+
/*
* Countdown for host blocking with no commands outstanding.
*/
--
2.16.4