netdev - [PATCH net 6/7] qeth: do not turn on SG per default

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Message-Id: <20160915123927.86579-7-ubraun@linux.vnet.ibm.com>
Date:   Thu, 15 Sep 2016 14:39:26 +0200
From:   Ursula Braun <ubraun@...ux.vnet.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
        ubraun@...ux.vnet.ibm.com
Subject: [PATCH net 6/7] qeth: do not turn on SG per default

According to recent performance measurements, turning on net_device
feature NETIF_F_SG only behaves well, but turning on feature
NETIF_F_GSO shows bad results. Since the kernel activates NETIF_F_GSO
automatically as soon as the driver configures feature NETIF_F_SG, qeth
should not activate feature NETIF_F_SG per default, until the qeth
problems with NETIF_F_GSO are solved.

Signed-off-by: Ursula Braun <ubraun@...ux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@...ux.vnet.ibm.com>
---
 drivers/s390/net/qeth_l2_main.c | 2 --
 drivers/s390/net/qeth_l3_main.c | 1 -
 2 files changed, 3 deletions(-)

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 2081c18..bb27058 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -1124,8 +1124,6 @@ static int qeth_l2_setup_netdev(struct qeth_card *card)
 			card->dev->hw_features |= NETIF_F_RXCSUM;
 			card->dev->vlan_features |= NETIF_F_RXCSUM;
 		}
-		/* Turn on SG per default */
-		card->dev->features |= NETIF_F_SG;
 	}
 	card->info.broadcast_capable = 1;
 	qeth_l2_request_initial_mac(card);
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 0cbbc80..c00f6db 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -3120,7 +3120,6 @@ static int qeth_l3_setup_netdev(struct qeth_card *card)
 				card->dev->vlan_features = NETIF_F_SG |
 					NETIF_F_RXCSUM | NETIF_F_IP_CSUM |
 					NETIF_F_TSO;
-				card->dev->features = NETIF_F_SG;
 			}
 		}
 	} else if (card->info.type == QETH_CARD_TYPE_IQD) {
-- 
2.8.4