netdev - [PATCH net 4/5] nfp: limit the number of TSO segments

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Date:   Wed,  7 Feb 2018 20:55:25 -0800
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, oss-drivers@...ronome.com,
        Jakub Kicinski <jakub.kicinski@...ronome.com>
Subject: [PATCH net 4/5] nfp: limit the number of TSO segments

Most FWs limit the number of TSO segments a frame can produce
to 64.  This is for fairness and efficiency (of FW datapath)
reasons.  If a frame with larger number of segments is submitted
the FW will drop it.

Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
---
 drivers/net/ethernet/netronome/nfp/nfp_net_common.c | 2 ++
 drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h   | 5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 19e989239af7..a05be0ab2713 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -3750,6 +3750,8 @@ static void nfp_net_netdev_init(struct nfp_net *nn)
 	netdev->min_mtu = ETH_MIN_MTU;
 	netdev->max_mtu = nn->max_mtu;
 
+	netdev->gso_max_segs = NFP_NET_LSO_MAX_SEGS;
+
 	netif_carrier_off(netdev);
 
 	nfp_net_set_ethtool_ops(netdev);
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h b/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h
index eeecef2caac6..4499a7333078 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h
@@ -59,9 +59,12 @@
 #define NFP_NET_RX_OFFSET               32
 
 /**
- * Maximum header size supported for LSO frames
+ * LSO parameters
+ * %NFP_NET_LSO_MAX_HDR_SZ:	Maximum header size supported for LSO frames
+ * %NFP_NET_LSO_MAX_SEGS:	Maximum number of segments LSO frame can produce
  */
 #define NFP_NET_LSO_MAX_HDR_SZ		255
+#define NFP_NET_LSO_MAX_SEGS		64
 
 /**
  * Prepend field types
-- 
2.15.1