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mlx4: xdp: Allow raising MTU up to one page minus eth and vlan hdrs

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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@fb.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau 2016-12-07 15:53:12 -08:00 committed by David S. Miller
parent 17bedab272
commit b45f0674b9
2 changed files with 43 additions and 29 deletions
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28
drivers/net/ethernet/mellanox/mlx4/en_netdev.c
View File

@ -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)

44
drivers/net/ethernet/mellanox/mlx4/en_rx.c
View File

@ -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;