igc: Add support for TSO

TCP segmentation offload allows a device to segment a single frame
into multiple frames with a data payload size specified in socket buffer.
As a result we can now send data approximately up to seven percents fast
than was previously possible on my system.

Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
index 2121fc34e30031470deacb6a5e284f7d9d33068f..9e34b0969322ceb43ffbcd7b2c43744cb5aabc65 100644 (file)
--- a/drivers/net/ethernet/intel/igc/igc_defines.h
+++ b/drivers/net/ethernet/intel/igc/igc_defines.h
@@ -282,6 +282,10 @@
 #define IGC_TXD_STAT_TC                0x00000004 /* Tx Underrun */
 #define IGC_TXD_EXTCMD_TSTAMP  0x00000010 /* IEEE1588 Timestamp packet */
 
+/* IPSec Encrypt Enable */
+#define IGC_ADVTXD_L4LEN_SHIFT 8  /* Adv ctxt L4LEN shift */
+#define IGC_ADVTXD_MSS_SHIFT   16 /* Adv ctxt MSS shift */
+
 /* Transmit Control */
 #define IGC_TCTL_EN            0x00000002 /* enable Tx */
 #define IGC_TCTL_PSP           0x00000008 /* pad short packets */

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index a8f8d279f3b1218ae6b4f4ec908e397c65e616ea..d9d5425fe8d998f323d056aa2b1f7da8d92b3902 100644 (file)
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -1000,6 +1000,10 @@ static u32 igc_tx_cmd_type(struct sk_buff *skb, u32 tx_flags)
                       IGC_ADVTXD_DCMD_DEXT |
                       IGC_ADVTXD_DCMD_IFCS;
 
+       /* set segmentation bits for TSO */
+       cmd_type |= IGC_SET_FLAG(tx_flags, IGC_TX_FLAGS_TSO,
+                                (IGC_ADVTXD_DCMD_TSE));
+
        /* set timestamp bit if present */
        cmd_type |= IGC_SET_FLAG(tx_flags, IGC_TX_FLAGS_TSTAMP,
                                 (IGC_ADVTXD_MAC_TSTAMP));
@@ -1171,6 +1175,100 @@ static int igc_tx_map(struct igc_ring *tx_ring,
        return -1;
 }
 
+static int igc_tso(struct igc_ring *tx_ring,
+                  struct igc_tx_buffer *first,
+                  u8 *hdr_len)
+{
+       u32 vlan_macip_lens, type_tucmd, mss_l4len_idx;
+       struct sk_buff *skb = first->skb;
+       union {
+               struct iphdr *v4;
+               struct ipv6hdr *v6;
+               unsigned char *hdr;
+       } ip;
+       union {
+               struct tcphdr *tcp;
+               struct udphdr *udp;
+               unsigned char *hdr;
+       } l4;
+       u32 paylen, l4_offset;
+       int err;
+
+       if (skb->ip_summed != CHECKSUM_PARTIAL)
+               return 0;
+
+       if (!skb_is_gso(skb))
+               return 0;
+
+       err = skb_cow_head(skb, 0);
+       if (err < 0)
+               return err;
+
+       ip.hdr = skb_network_header(skb);
+       l4.hdr = skb_checksum_start(skb);
+
+       /* ADV DTYP TUCMD MKRLOC/ISCSIHEDLEN */
+       type_tucmd = IGC_ADVTXD_TUCMD_L4T_TCP;
+
+       /* initialize outer IP header fields */
+       if (ip.v4->version == 4) {
+               unsigned char *csum_start = skb_checksum_start(skb);
+               unsigned char *trans_start = ip.hdr + (ip.v4->ihl * 4);
+
+               /* IP header will have to cancel out any data that
+                * is not a part of the outer IP header
+                */
+               ip.v4->check = csum_fold(csum_partial(trans_start,
+                                                     csum_start - trans_start,
+                                                     0));
+               type_tucmd |= IGC_ADVTXD_TUCMD_IPV4;
+
+               ip.v4->tot_len = 0;
+               first->tx_flags |= IGC_TX_FLAGS_TSO |
+                                  IGC_TX_FLAGS_CSUM |
+                                  IGC_TX_FLAGS_IPV4;
+       } else {
+               ip.v6->payload_len = 0;
+               first->tx_flags |= IGC_TX_FLAGS_TSO |
+                                  IGC_TX_FLAGS_CSUM;
+       }
+
+       /* determine offset of inner transport header */
+       l4_offset = l4.hdr - skb->data;
+
+       /* remove payload length from inner checksum */
+       paylen = skb->len - l4_offset;
+       if (type_tucmd & IGC_ADVTXD_TUCMD_L4T_TCP) {
+               /* compute length of segmentation header */
+               *hdr_len = (l4.tcp->doff * 4) + l4_offset;
+               csum_replace_by_diff(&l4.tcp->check,
+                                    (__force __wsum)htonl(paylen));
+       } else {
+               /* compute length of segmentation header */
+               *hdr_len = sizeof(*l4.udp) + l4_offset;
+               csum_replace_by_diff(&l4.udp->check,
+                                    (__force __wsum)htonl(paylen));
+       }
+
+       /* update gso size and bytecount with header size */
+       first->gso_segs = skb_shinfo(skb)->gso_segs;
+       first->bytecount += (first->gso_segs - 1) * *hdr_len;
+
+       /* MSS L4LEN IDX */
+       mss_l4len_idx = (*hdr_len - l4_offset) << IGC_ADVTXD_L4LEN_SHIFT;
+       mss_l4len_idx |= skb_shinfo(skb)->gso_size << IGC_ADVTXD_MSS_SHIFT;
+
+       /* VLAN MACLEN IPLEN */
+       vlan_macip_lens = l4.hdr - ip.hdr;
+       vlan_macip_lens |= (ip.hdr - skb->data) << IGC_ADVTXD_MACLEN_SHIFT;
+       vlan_macip_lens |= first->tx_flags & IGC_TX_FLAGS_VLAN_MASK;
+
+       igc_tx_ctxtdesc(tx_ring, first, vlan_macip_lens,
+                       type_tucmd, mss_l4len_idx);
+
+       return 1;
+}
+
 static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb,
                                       struct igc_ring *tx_ring)
 {
@@ -1180,6 +1278,7 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb,
        u32 tx_flags = 0;
        unsigned short f;
        u8 hdr_len = 0;
+       int tso = 0;
 
        /* need: 1 descriptor per page * PAGE_SIZE/IGC_MAX_DATA_PER_TXD,
         *      + 1 desc for skb_headlen/IGC_MAX_DATA_PER_TXD,
@@ -1226,10 +1325,20 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb,
        first->tx_flags = tx_flags;
        first->protocol = protocol;
 
-       igc_tx_csum(tx_ring, first);
+       tso = igc_tso(tx_ring, first, &hdr_len);
+       if (tso < 0)
+               goto out_drop;
+       else if (!tso)
+               igc_tx_csum(tx_ring, first);
 
        igc_tx_map(tx_ring, first, hdr_len);
 
+       return NETDEV_TX_OK;
+
+out_drop:
+       dev_kfree_skb_any(first->skb);
+       first->skb = NULL;
+
        return NETDEV_TX_OK;
 }
 
@@ -4589,6 +4698,8 @@ static int igc_probe(struct pci_dev *pdev,
 
        /* Add supported features to the features list*/
        netdev->features |= NETIF_F_SG;
+       netdev->features |= NETIF_F_TSO;
+       netdev->features |= NETIF_F_TSO6;
        netdev->features |= NETIF_F_RXCSUM;
        netdev->features |= NETIF_F_HW_CSUM;
        netdev->features |= NETIF_F_SCTP_CRC;