tree c01e56696192ee4672f747ce53c49daaabc5ec55
parent ad6048325c7807818c6c49e485660143d97a622e
author Xiang Chen <chenxiang66@hisilicon.com> 1497454393 +0800
committer Martin K. Petersen <martin.petersen@oracle.com> 1497922285 -0400

scsi: hisi_sas: optimise the usage of hisi_hba.lock

Currently hisi_hba.lock is locked to deliver and receive a command
to/from any hw queue. This causes much contention at high data-rates.

To boost performance, lock on a per queue basis for sending and
receiving commands to/from hw.

Certain critical regions still need to be locked in the delivery and
completion stages with hisi_hba.lock.

New element hisi_sas_device.dq is added to store the delivery queue for
a device, so it does not need to be needlessly re-calculated for every
task.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>