Re: [PATCH v2 1/3] igb: Add UDP segmentation offload support

[Josh Hunt]

On 10/11/19 8:29 AM, Alexander Duyck wrote:
On Thu, 2019-10-10 at 20:25 -0400, Josh Hunt wrote:
Based on a series from Alexander Duyck this change adds UDP segmentation
offload support to the igb driver.

CC: Alexander Duyck <alexander.h.du...@intel.com>
CC: Willem de Bruijn <will...@google.com>
Signed-off-by: Josh Hunt <joh...@akamai.com>
---
  drivers/net/ethernet/intel/igb/e1000_82575.h |  1 +
  drivers/net/ethernet/intel/igb/igb_main.c    | 23 +++++++++++++++++------
  2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/e1000_82575.h 
b/drivers/net/ethernet/intel/igb/e1000_82575.h
index 6ad775b1a4c5..63ec253ac788 100644
--- a/drivers/net/ethernet/intel/igb/e1000_82575.h
+++ b/drivers/net/ethernet/intel/igb/e1000_82575.h
@@ -127,6 +127,7 @@ struct e1000_adv_tx_context_desc {
  };
  
  #define E1000_ADVTXD_MACLEN_SHIFT    9  /* Adv ctxt desc mac len shift */
+#define E1000_ADVTXD_TUCMD_L4T_UDP 0x00000000  /* L4 Packet TYPE of UDP */
  #define E1000_ADVTXD_TUCMD_IPV4    0x00000400  /* IP Packet Type: 1=IPv4 */
  #define E1000_ADVTXD_TUCMD_L4T_TCP 0x00000800  /* L4 Packet TYPE of TCP */
  #define E1000_ADVTXD_TUCMD_L4T_SCTP 0x00001000 /* L4 packet TYPE of SCTP */
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c 
b/drivers/net/ethernet/intel/igb/igb_main.c
index 105b0624081a..4131bc8b079e 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2516,6 +2516,7 @@ igb_features_check(struct sk_buff *skb, struct net_device 
*dev,
        if (unlikely(mac_hdr_len > IGB_MAX_MAC_HDR_LEN))
                return features & ~(NETIF_F_HW_CSUM |
                                    NETIF_F_SCTP_CRC |
+                                   NETIF_F_GSO_UDP_L4 |
                                    NETIF_F_HW_VLAN_CTAG_TX |
                                    NETIF_F_TSO |
                                    NETIF_F_TSO6);
@@ -2524,6 +2525,7 @@ igb_features_check(struct sk_buff *skb, struct net_device 
*dev,
        if (unlikely(network_hdr_len >  IGB_MAX_NETWORK_HDR_LEN))
                return features & ~(NETIF_F_HW_CSUM |
                                    NETIF_F_SCTP_CRC |
+                                   NETIF_F_GSO_UDP_L4 |
                                    NETIF_F_TSO |
                                    NETIF_F_TSO6);
  
@@ -3120,7 +3122,7 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
                            NETIF_F_HW_CSUM;
  
  	if (hw->mac.type >= e1000_82576)
-               netdev->features |= NETIF_F_SCTP_CRC;
+               netdev->features |= NETIF_F_SCTP_CRC | NETIF_F_GSO_UDP_L4;
  
  	if (hw->mac.type >= e1000_i350)
                netdev->features |= NETIF_F_HW_TC;
@@ -5694,6 +5696,7 @@ static int igb_tso(struct igb_ring *tx_ring,
        } ip;
        union {
                struct tcphdr *tcp;
+               struct udphdr *udp;
                unsigned char *hdr;
        } l4;
        u32 paylen, l4_offset;
@@ -5713,7 +5716,8 @@ static int igb_tso(struct igb_ring *tx_ring,
        l4.hdr = skb_checksum_start(skb);
  
  	/* ADV DTYP TUCMD MKRLOC/ISCSIHEDLEN */
-       type_tucmd = E1000_ADVTXD_TUCMD_L4T_TCP;
+       type_tucmd = (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)) ?
+                     E1000_ADVTXD_TUCMD_L4T_TCP : E1000_ADVTXD_TUCMD_L4T_UDP;

The logic here seems a bit convoluted. Instead of testing for
'!SKB_GSO_UDP_L4' why not just make L4T_UDP the first option and drop the
'!'? That will make the TCP offload the default case rather than the UDP
offload.

The same applies to the other 2 patches.

OK sure. I think I was trying to keep the TCP case first for some 
reason, but agree that I should probably just reverse the order. Will 
send a v3.

Josh