Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Content-Type: text/plain; charset="UTF-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        "Eda Zhou" <ezhou@redhat.com>, "Ewan D. Milne" <emilne@redhat.com>,
        "Himanshu Madhani" <himanshu.madhani@cavium.com>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.526556446@decadent.org.uk>
Subject: [PATCH 3.16 120/366] scsi: qla2xxx: Fix setting lower transfer
 speed if GPSC fails
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Himanshu Madhani <himanshu.madhani@cavium.com>

commit 413c2f33489b134e3cc65d9c3ff7861e8fdfe899 upstream.

This patch prevents driver from setting lower default speed of 1 GB/sec,
if the switch does not support Get Port Speed Capabilities (GPSC)
command. Setting this default speed results into much lower write
performance for large sequential WRITE.  This patch modifies driver to
check for gpsc_supported flags and prevents driver from issuing
MBC_SET_PORT_PARAM (001Ah) to set default speed of 1 GB/sec. If driver
does not send this mailbox command, firmware assumes maximum supported
link speed and will operate at the max speed.

Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reported-by: Eda Zhou <ezhou@redhat.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Tested-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/scsi/qla2xxx/qla_init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -3205,7 +3205,8 @@ qla2x00_iidma_fcport(scsi_qla_host_t *vh
 		return;
 
 	if (fcport->fp_speed == PORT_SPEED_UNKNOWN ||
-	    fcport->fp_speed > ha->link_data_rate)
+	    fcport->fp_speed > ha->link_data_rate ||
+	    !ha->flags.gpsc_supported)
 		return;
 
 	rval = qla2x00_set_idma_speed(vha, fcport->loop_id, fcport->fp_speed,