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@fb.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.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 f441eda..c97d25b 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)