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Message-ID: <1480821446-4122277-3-git-send-email-kafai@fb.com>
Date: Sat, 3 Dec 2016 19:17:24 -0800
From: Martin KaFai Lau <kafai@...com>
To: <netdev@...r.kernel.org>
CC: Alexei Starovoitov <ast@...com>,
Brenden Blanco <bblanco@...mgrid.com>,
Daniel Borkmann <daniel@...earbox.net>,
David Miller <davem@...emloft.net>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Saeed Mahameed <saeedm@...lanox.com>,
Tariq Toukan <tariqt@...lanox.com>,
Kernel Team <kernel-team@...com>
Subject: [PATCH v2 net-next 2/4] 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 <kafai@...com>
---
drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 28 +++++++++++-----
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 46 ++++++++++++++------------
2 files changed, 44 insertions(+), 30 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 49a81f1fc1d6..311c14153b8b 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)) {
@@ -2710,10 +2724,8 @@ 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;
- }
-
- 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++;
+ 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 = 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;
--
2.5.1
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