Re: [PATCH v6 net-next 13/13] mlx5: support BIG TCP packets
From: Saeed Mahameed <saeedm@nvidia.com>
Date: 2022-05-12 08:40:31
On 09 May 20:32, Eric Dumazet wrote:
From: Coco Li <redacted> mlx5 supports LSOv2. IPv6 gro/tcp stacks insert a temporary Hop-by-Hop header with JUMBO TLV for big packets. We need to ignore/skip this HBH header when populating TX descriptor.
Sorry i didn't go through all the documentations or previous discussions,
please bare with me, so why not clear HBH just before calling the
driver xmit ndo ?
Or if HBH has to stick, why not provide some helpers to the driver, to make
it less intrusive to the driver.
mlx5_xmit_skb() {
skb_remove_hbh(skb);
populate tx descriptor as usual;
skb_restore_hbh(skb); //must be before doorbell
ring doorbell
}
quoted hunk ↗ jump to hunk
Note that ipv6_has_hopopt_jumbo() only recognizes very specific packet layout, thus mlx5e_sq_xmit_wqe() is taking care of this layout only. v2: clear hopbyhop in mlx5e_tx_get_gso_ihs() v4: fix compile error for CONFIG_MLX5_CORE_IPOIB=y Signed-off-by: Coco Li <redacted> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Leon Romanovsky <leon@kernel.org> --- .../net/ethernet/mellanox/mlx5/core/en_main.c | 1 + .../net/ethernet/mellanox/mlx5/core/en_tx.c | 84 +++++++++++++++---- 2 files changed, 69 insertions(+), 16 deletions(-)diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index d27986869b8ba070d1a4f8bcdc7e14ab54ae984e..bf3bca79e160124abd128ac1e9910cb2f39a39ff 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c@@ -4920,6 +4920,7 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)netdev->priv_flags |= IFF_UNICAST_FLT; + netif_set_tso_max_size(netdev, GSO_MAX_SIZE); mlx5e_set_netdev_dev_addr(netdev); mlx5e_ipsec_build_netdev(priv); mlx5e_ktls_build_netdev(priv);diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c index 2dc48406cd08d21ff94f665cd61ab9227f351215..b4fc45ba1b347fb9ad0f46b9c091cc45e4d3d84f 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c@@ -40,6 +40,7 @@#include "en_accel/en_accel.h" #include "en_accel/ipsec_rxtx.h" #include "en/ptp.h" +#include <net/ipv6.h> static void mlx5e_dma_unmap_wqe_err(struct mlx5e_txqsq *sq, u8 num_dma) {@@ -130,23 +131,32 @@ mlx5e_txwqe_build_eseg_csum(struct mlx5e_txqsq *sq, struct sk_buff *skb,sq->stats->csum_none++; } +/* Returns the number of header bytes that we plan + * to inline later in the transmit descriptor + */ static inline u16 -mlx5e_tx_get_gso_ihs(struct mlx5e_txqsq *sq, struct sk_buff *skb) +mlx5e_tx_get_gso_ihs(struct mlx5e_txqsq *sq, struct sk_buff *skb, int *hopbyhop) { struct mlx5e_sq_stats *stats = sq->stats; u16 ihs; + *hopbyhop = 0; if (skb->encapsulation) { ihs = skb_inner_transport_offset(skb) + inner_tcp_hdrlen(skb); stats->tso_inner_packets++; stats->tso_inner_bytes += skb->len - ihs; } else { - if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) + if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) { ihs = skb_transport_offset(skb) + sizeof(struct udphdr); - else + } else { ihs = skb_transport_offset(skb) + tcp_hdrlen(skb); + if (ipv6_has_hopopt_jumbo(skb)) { + *hopbyhop = sizeof(struct hop_jumbo_hdr); + ihs -= sizeof(struct hop_jumbo_hdr); + } + } stats->tso_packets++; - stats->tso_bytes += skb->len - ihs; + stats->tso_bytes += skb->len - ihs - *hopbyhop; } return ihs;@@ -208,6 +218,7 @@ struct mlx5e_tx_attr {__be16 mss; u16 insz; u8 opcode; + u8 hopbyhop; }; struct mlx5e_tx_wqe_attr {@@ -244,14 +255,16 @@ static void mlx5e_sq_xmit_prepare(struct mlx5e_txqsq *sq, struct sk_buff *skb,struct mlx5e_sq_stats *stats = sq->stats; if (skb_is_gso(skb)) { - u16 ihs = mlx5e_tx_get_gso_ihs(sq, skb); + int hopbyhop; + u16 ihs = mlx5e_tx_get_gso_ihs(sq, skb, &hopbyhop); *attr = (struct mlx5e_tx_attr) { .opcode = MLX5_OPCODE_LSO, .mss = cpu_to_be16(skb_shinfo(skb)->gso_size), .ihs = ihs, .num_bytes = skb->len + (skb_shinfo(skb)->gso_segs - 1) * ihs, - .headlen = skb_headlen(skb) - ihs, + .headlen = skb_headlen(skb) - ihs - hopbyhop, + .hopbyhop = hopbyhop, }; stats->packets += skb_shinfo(skb)->gso_segs;@@ -365,7 +378,8 @@ mlx5e_sq_xmit_wqe(struct mlx5e_txqsq *sq, struct sk_buff *skb,struct mlx5_wqe_eth_seg *eseg; struct mlx5_wqe_data_seg *dseg; struct mlx5e_tx_wqe_info *wi; - + u16 ihs = attr->ihs; + struct ipv6hdr *h6; struct mlx5e_sq_stats *stats = sq->stats; int num_dma;@@ -379,15 +393,36 @@ mlx5e_sq_xmit_wqe(struct mlx5e_txqsq *sq, struct sk_buff *skb,eseg->mss = attr->mss; - if (attr->ihs) { - if (skb_vlan_tag_present(skb)) { - eseg->inline_hdr.sz |= cpu_to_be16(attr->ihs + VLAN_HLEN); - mlx5e_insert_vlan(eseg->inline_hdr.start, skb, attr->ihs); + if (ihs) { + u8 *start = eseg->inline_hdr.start; + + if (unlikely(attr->hopbyhop)) { + /* remove the HBH header. + * Layout: [Ethernet header][IPv6 header][HBH][TCP header] + */ + if (skb_vlan_tag_present(skb)) { + mlx5e_insert_vlan(start, skb, ETH_HLEN + sizeof(*h6)); + ihs += VLAN_HLEN; + h6 = (struct ipv6hdr *)(start + sizeof(struct vlan_ethhdr)); + } else { + memcpy(start, skb->data, ETH_HLEN + sizeof(*h6)); + h6 = (struct ipv6hdr *)(start + 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 if (skb_vlan_tag_present(skb)) { + mlx5e_insert_vlan(start, skb, ihs); + ihs += VLAN_HLEN; stats->added_vlan_packets++; } else { - eseg->inline_hdr.sz |= cpu_to_be16(attr->ihs); - memcpy(eseg->inline_hdr.start, skb->data, attr->ihs); + memcpy(start, skb->data, ihs); } + eseg->inline_hdr.sz |= cpu_to_be16(ihs); dseg += wqe_attr->ds_cnt_inl; } else if (skb_vlan_tag_present(skb)) { eseg->insert.type = cpu_to_be16(MLX5_ETH_WQE_INSERT_VLAN);@@ -398,7 +433,7 @@ mlx5e_sq_xmit_wqe(struct mlx5e_txqsq *sq, struct sk_buff *skb,} dseg += wqe_attr->ds_cnt_ids; - num_dma = mlx5e_txwqe_build_dsegs(sq, skb, skb->data + attr->ihs, + num_dma = mlx5e_txwqe_build_dsegs(sq, skb, skb->data + attr->ihs + attr->hopbyhop, attr->headlen, dseg); if (unlikely(num_dma < 0)) goto err_drop;@@ -918,12 +953,29 @@ void mlx5i_sq_xmit(struct mlx5e_txqsq *sq, struct sk_buff *skb,eseg->mss = attr.mss; if (attr.ihs) { - memcpy(eseg->inline_hdr.start, skb->data, attr.ihs); + if (unlikely(attr.hopbyhop)) { + struct ipv6hdr *h6; + + /* remove the HBH header. + * Layout: [Ethernet header][IPv6 header][HBH][TCP header] + */ + memcpy(eseg->inline_hdr.start, skb->data, ETH_HLEN + sizeof(*h6)); + h6 = (struct ipv6hdr *)((char *)eseg->inline_hdr.start + 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 { + memcpy(eseg->inline_hdr.start, skb->data, attr.ihs); + } eseg->inline_hdr.sz = cpu_to_be16(attr.ihs); dseg += wqe_attr.ds_cnt_inl; } - num_dma = mlx5e_txwqe_build_dsegs(sq, skb, skb->data + attr.ihs, + num_dma = mlx5e_txwqe_build_dsegs(sq, skb, skb->data + attr.ihs + attr.hopbyhop, attr.headlen, dseg); if (unlikely(num_dma < 0)) goto err_drop; -- 2.36.0.512.ge40c2bad7a-goog