scsi: hisi_sas: save completion queue read pointer
authorJohn Garry <john.garry@huawei.com>
Tue, 6 Sep 2016 15:36:11 +0000 (23:36 +0800)
committerMartin K. Petersen <martin.petersen@oracle.com>
Wed, 14 Sep 2016 16:54:17 +0000 (12:54 -0400)
commite6c346f303d41b8799ea224d0faf1b2caa1c98db
tree5ab81caef92f48c4960acefc2e66605b2e05eab4
parentc4a11827b760ef8dcda26b5731d072b1d8fb7c81
scsi: hisi_sas: save completion queue read pointer

Optimise by saving an avoidable read in the cq interrupt.  The queue
read pointer will only be updated by software, so don't bother
re-reading what was already written in the previous interrupt.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
drivers/scsi/hisi_sas/hisi_sas.h
drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
drivers/scsi/hisi_sas/hisi_sas_v2_hw.c