On 01/22/2016 02:41 PM, Johannes Thumshirn wrote:

Allow the activation of the scsi-mq feature on a per-driver bassis as opposed
to the current stack global (de)activation.

This allows us to have setups which can combine "slow" rotational media and
fast media on two different HBA types.

The following is from a host with rotational disks behind a HP SAS Adapter and
a fibre channel array behind a Emulex FC Adapter. The hpsa driver does not
support scsi-mq yet (and has rotational disks attached to it), but the lpfc
does. This patch allows an optimal combination of the scsi-mq enabled lpfc
driver and the hpsa driver which still uses a single queue scsi layer and thus
can make use of IO schedulers.

host:~ # cat /sys/block/sd?/queue/scheduler
noop deadline [cfq]
none
none
none
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Signed-off-by: Johannes Thumshirn <redacted>
---
 drivers/scsi/fnic/fnic_main.c | 10 ++++++++++
 drivers/scsi/hosts.c          |  2 +-
 drivers/scsi/lpfc/lpfc_init.c |  8 ++++++++
 drivers/scsi/virtio_scsi.c    | 11 +++++++++++
 include/scsi/scsi_host.h      |  3 ---
 5 files changed, 30 insertions(+), 4 deletions(-)

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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