From b3a52e791efd341a9a4e9065c667041c822661f0 Mon Sep 17 00:00:00 2001 From: "Stephen M. Cameron" Date: Thu, 29 May 2014 10:53:23 -0500 Subject: hpsa: avoid unnecessary readl on every command submission for controllers which support either of the ioaccel transport methods. Signed-off-by: Stephen M. Cameron Reviewed-by: Mike Miller Reviewed-by: Joe Handzik Signed-off-by: Christoph Hellwig --- drivers/scsi/hpsa.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/scsi/hpsa.c') diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c index 3b70e66838ad..3e501df02e35 100644 --- a/drivers/scsi/hpsa.c +++ b/drivers/scsi/hpsa.c @@ -7330,6 +7330,13 @@ static void hpsa_enter_performant_mode(struct ctlr_info *h, u32 trans_support) * 10 = 6 s/g entry or 24k */ + /* If the controller supports either ioaccel method then + * we can also use the RAID stack submit path that does not + * perform the superfluous readl() after each command submission. + */ + if (trans_support & (CFGTBL_Trans_io_accel1 | CFGTBL_Trans_io_accel2)) + access = SA5_performant_access_no_read; + /* Controller spec: zero out this buffer. */ for (i = 0; i < h->nreply_queues; i++) memset(h->reply_queue[i].head, 0, h->reply_queue_size); -- cgit v1.2.3