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

[Simon Horman]

On Wed, Feb 07, 2018 at 08:55:25PM -0800, Jakub Kicinski wrote:
> 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 

Reviewed-by: Simon Horman 

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

[Jakub Kicinski]

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 
---
 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