mlx4: support BIG TCP packets

mlx4 supports LSOv2 just fine.

IPv6 stack inserts a temporary Hop-by-Hop header
with JUMBO TLV for big packets.

We need to ignore the HBH header when populating TX descriptor.

Tested:

Before: (not enabling bigger TSO/GRO packets)

ip link set dev eth0 gso_max_size 65536 gro_max_size 65536

netperf -H lpaa18 -t TCP_RR -T2,2 -l 10 -Cc -- -r 70000,70000
MIGRATED TCP REQUEST/RESPONSE TEST from ::0 (::) port 0 AF_INET6 to lpaa18.prod.google.com () port 0 AF_INET6 : first burst 0 : cpu bind
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % S    us/Tr   us/Tr

262144 540000 70000   70000  10.00   6591.45  0.86   1.34   62.490  97.446
262144 540000

After: (enabling bigger TSO/GRO packets)

ip link set dev eth0 gso_max_size 185000 gro_max_size 185000

netperf -H lpaa18 -t TCP_RR -T2,2 -l 10 -Cc -- -r 70000,70000
MIGRATED TCP REQUEST/RESPONSE TEST from ::0 (::) port 0 AF_INET6 to lpaa18.prod.google.com () port 0 AF_INET6 : first burst 0 : cpu bind
Local /Remote
Socket Size   Request Resp.  Elapsed Trans.   CPU    CPU    S.dem   S.dem
Send   Recv   Size    Size   Time    Rate     local  remote local   remote
bytes  bytes  bytes   bytes  secs.   per sec  % S    % S    us/Tr   us/Tr

262144 540000 70000   70000  10.00   8383.95  0.95   1.01   54.432  57.584
262144 540000

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Acked-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index c61dc7a..ca4b93a 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -3417,6 +3417,9 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
        dev->min_mtu = ETH_MIN_MTU;
        dev->max_mtu = priv->max_mtu;
 
+       /* supports LSOv2 packets. */
+       netif_set_tso_max_size(dev, GSO_MAX_SIZE);
+
        mdev->pndev[port] = dev;
        mdev->upper[port] = NULL;
 

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index f777151..af3b2b5 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -43,6 +43,7 @@
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/indirect_call_wrapper.h>
+#include <net/ipv6.h>
 
 #include "mlx4_en.h"
 
@@ -634,19 +635,28 @@ static int get_real_size(const struct sk_buff *skb,
                         struct net_device *dev,
                         int *lso_header_size,
                         bool *inline_ok,
-                        void **pfrag)
+                        void **pfrag,
+                        int *hopbyhop)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
        int real_size;
 
        if (shinfo->gso_size) {
                *inline_ok = false;
-               if (skb->encapsulation)
+               *hopbyhop = 0;
+               if (skb->encapsulation) {
                        *lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
-               else
+               } else {
+                       /* Detects large IPV6 TCP packets and prepares for removal of
+                        * HBH header that has been pushed by ip6_xmit(),
+                        * mainly so that tcpdump can dissect them.
+                        */
+                       if (ipv6_has_hopopt_jumbo(skb))
+                               *hopbyhop = sizeof(struct hop_jumbo_hdr);
                        *lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
+               }
                real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE +
-                       ALIGN(*lso_header_size + 4, DS_SIZE);
+                       ALIGN(*lso_header_size - *hopbyhop + 4, DS_SIZE);
                if (unlikely(*lso_header_size != skb_headlen(skb))) {
                        /* We add a segment for the skb linear buffer only if
                         * it contains data */
@@ -873,6 +883,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        int desc_size;
        int real_size;
        u32 index, bf_index;
+       struct ipv6hdr *h6;
        __be32 op_own;
        int lso_header_size;
        void *fragptr = NULL;
@@ -881,6 +892,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
        bool stop_queue;
        bool inline_ok;
        u8 data_offset;
+       int hopbyhop;
        bool bf_ok;
 
        tx_ind = skb_get_queue_mapping(skb);
@@ -890,7 +902,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                goto tx_drop;
 
        real_size = get_real_size(skb, shinfo, dev, &lso_header_size,
-                                 &inline_ok, &fragptr);
+                                 &inline_ok, &fragptr, &hopbyhop);
        if (unlikely(!real_size))
                goto tx_drop_count;
 
@@ -943,7 +955,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                data = &tx_desc->data;
                data_offset = offsetof(struct mlx4_en_tx_desc, data);
        } else {
-               int lso_align = ALIGN(lso_header_size + 4, DS_SIZE);
+               int lso_align = ALIGN(lso_header_size - hopbyhop + 4, DS_SIZE);
 
                data = (void *)&tx_desc->lso + lso_align;
                data_offset = offsetof(struct mlx4_en_tx_desc, lso) + lso_align;
@@ -1008,14 +1020,31 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
                        ((ring->prod & ring->size) ?
                                cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
 
+               lso_header_size -= hopbyhop;
                /* Fill in the LSO prefix */
                tx_desc->lso.mss_hdr_size = cpu_to_be32(
                        shinfo->gso_size << 16 | lso_header_size);
 
-               /* Copy headers;
-                * note that we already verified that it is linear */
-               memcpy(tx_desc->lso.header, skb->data, lso_header_size);
 
+               if (unlikely(hopbyhop)) {
+                       /* remove the HBH header.
+                        * Layout: [Ethernet header][IPv6 header][HBH][TCP header]
+                        */
+                       memcpy(tx_desc->lso.header, skb->data, ETH_HLEN + sizeof(*h6));
+                       h6 = (struct ipv6hdr *)((char *)tx_desc->lso.header + ETH_HLEN);
+                       h6->nexthdr = IPPROTO_TCP;
+                       /* Copy the TCP header after the IPv6 one */
+                       memcpy(h6 + 1,
+                              skb->data + ETH_HLEN + sizeof(*h6) +
+                                       sizeof(struct hop_jumbo_hdr),
+                              tcp_hdrlen(skb));
+                       /* Leave ipv6 payload_len set to 0, as LSO v2 specs request. */
+               } else {
+                       /* Copy headers;
+                        * note that we already verified that it is linear
+                        */
+                       memcpy(tx_desc->lso.header, skb->data, lso_header_size);
+               }
                ring->tso_packets++;
 
                i = shinfo->gso_segs;