From b45f0674b997ee769907d6092dfa9ee8f59bb51d Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 7 Dec 2016 15:53:12 -0800 Subject: [PATCH] mlx4: xdp: Allow raising MTU up to one page minus eth and vlan hdrs When XDP is active in mlx4, mlx4 is using one page/pkt. At the same time (i.e. when XDP is active), it is currently limiting MTU to be FRAG_SZ0 - ETH_HLEN - (2 * VLAN_HLEN) which is 1514 in x86. AFAICT, we can at least raise the MTU limit up to PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN) which this patch is doing. It will be useful in the next patch which allows XDP program to extend the packet by adding new header(s). Note: In the earlier XDP patches, there is already existing guard to ensure the page/pkt scheme only applies when XDP is active in mlx4. Signed-off-by: Martin KaFai Lau Acked-by: Saeed Mahameed Signed-off-by: David S. Miller --- .../net/ethernet/mellanox/mlx4/en_netdev.c | 28 ++++++++---- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 44 ++++++++++--------- 2 files changed, 43 insertions(+), 29 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c index f441eda63bec..c97d25b06444 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c @@ -51,6 +51,8 @@ #include "mlx4_en.h" #include "en_port.h" +#define MLX4_EN_MAX_XDP_MTU ((int)(PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN))) + int mlx4_en_setup_tc(struct net_device *dev, u8 up) { struct mlx4_en_priv *priv = netdev_priv(dev); @@ -2249,6 +2251,19 @@ void mlx4_en_destroy_netdev(struct net_device *dev) free_netdev(dev); } +static bool mlx4_en_check_xdp_mtu(struct net_device *dev, int mtu) +{ + struct mlx4_en_priv *priv = netdev_priv(dev); + + if (mtu > MLX4_EN_MAX_XDP_MTU) { + en_err(priv, "mtu:%d > max:%d when XDP prog is attached\n", + mtu, MLX4_EN_MAX_XDP_MTU); + return false; + } + + return true; +} + static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu) { struct mlx4_en_priv *priv = netdev_priv(dev); @@ -2258,11 +2273,10 @@ static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu) en_dbg(DRV, priv, "Change MTU called - current:%d new:%d\n", dev->mtu, new_mtu); - if (priv->tx_ring_num[TX_XDP] && MLX4_EN_EFF_MTU(new_mtu) > FRAG_SZ0) { - en_err(priv, "MTU size:%d requires frags but XDP running\n", - new_mtu); - return -EOPNOTSUPP; - } + if (priv->tx_ring_num[TX_XDP] && + !mlx4_en_check_xdp_mtu(dev, new_mtu)) + return -ENOTSUPP; + dev->mtu = new_mtu; if (netif_running(dev)) { @@ -2715,10 +2729,8 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog) return 0; } - if (priv->num_frags > 1) { - en_err(priv, "Cannot set XDP if MTU requires multiple frags\n"); + if (!mlx4_en_check_xdp_mtu(dev, dev->mtu)) return -EOPNOTSUPP; - } tmp = kzalloc(sizeof(*tmp), GFP_KERNEL); if (!tmp) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c index 6562f78b07f4..23e9d04d1ef4 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -1164,37 +1164,39 @@ static const int frag_sizes[] = { void mlx4_en_calc_rx_buf(struct net_device *dev) { - enum dma_data_direction dma_dir = PCI_DMA_FROMDEVICE; struct mlx4_en_priv *priv = netdev_priv(dev); int eff_mtu = MLX4_EN_EFF_MTU(dev->mtu); - int order = MLX4_EN_ALLOC_PREFER_ORDER; - u32 align = SMP_CACHE_BYTES; - int buf_size = 0; int i = 0; /* bpf requires buffers to be set up as 1 packet per page. * This only works when num_frags == 1. */ if (priv->tx_ring_num[TX_XDP]) { - dma_dir = PCI_DMA_BIDIRECTIONAL; - /* This will gain efficient xdp frame recycling at the expense - * of more costly truesize accounting + priv->frag_info[0].order = 0; + priv->frag_info[0].frag_size = eff_mtu; + priv->frag_info[0].frag_prefix_size = 0; + /* This will gain efficient xdp frame recycling at the + * expense of more costly truesize accounting */ - align = PAGE_SIZE; - order = 0; - } + priv->frag_info[0].frag_stride = PAGE_SIZE; + priv->frag_info[0].dma_dir = PCI_DMA_BIDIRECTIONAL; + i = 1; + } else { + int buf_size = 0; - while (buf_size < eff_mtu) { - priv->frag_info[i].order = order; - priv->frag_info[i].frag_size = - (eff_mtu > buf_size + frag_sizes[i]) ? - frag_sizes[i] : eff_mtu - buf_size; - priv->frag_info[i].frag_prefix_size = buf_size; - priv->frag_info[i].frag_stride = - ALIGN(priv->frag_info[i].frag_size, align); - priv->frag_info[i].dma_dir = dma_dir; - buf_size += priv->frag_info[i].frag_size; - i++; + while (buf_size < eff_mtu) { + priv->frag_info[i].order = MLX4_EN_ALLOC_PREFER_ORDER; + priv->frag_info[i].frag_size = + (eff_mtu > buf_size + frag_sizes[i]) ? + frag_sizes[i] : eff_mtu - buf_size; + priv->frag_info[i].frag_prefix_size = buf_size; + priv->frag_info[i].frag_stride = + ALIGN(priv->frag_info[i].frag_size, + SMP_CACHE_BYTES); + priv->frag_info[i].dma_dir = PCI_DMA_FROMDEVICE; + buf_size += priv->frag_info[i].frag_size; + i++; + } } priv->num_frags = i;