sfc: Enable setting of xdp_prog

Provide an ndo_bpf function to efx_netdev_ops that allows setting and
querying of xdp programs on an interface.

Also check that the MTU size isn't too big when setting a program or
when the MTU is explicitly set.

Signed-off-by: Charles McLachlan <cmclachlan@solarflare.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index bd04244..429fb26 100644 (file)
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -226,6 +226,8 @@ static void efx_fini_napi_channel(struct efx_channel *channel);
 static void efx_fini_struct(struct efx_nic *efx);
 static void efx_start_all(struct efx_nic *efx);
 static void efx_stop_all(struct efx_nic *efx);
+static int efx_xdp_setup_prog(struct efx_nic *efx, struct bpf_prog *prog);
+static int efx_xdp(struct net_device *dev, struct netdev_bpf *xdp);
 
 #define EFX_ASSERT_RESET_SERIALISED(efx)               \
        do {                                            \
@@ -2025,6 +2027,10 @@ static void efx_stop_all(struct efx_nic *efx)
 
 static void efx_remove_all(struct efx_nic *efx)
 {
+       rtnl_lock();
+       efx_xdp_setup_prog(efx, NULL);
+       rtnl_unlock();
+
        efx_remove_channels(efx);
        efx_remove_filters(efx);
 #ifdef CONFIG_SFC_SRIOV
@@ -2280,6 +2286,17 @@ static void efx_watchdog(struct net_device *net_dev)
        efx_schedule_reset(efx, RESET_TYPE_TX_WATCHDOG);
 }
 
+static unsigned int efx_xdp_max_mtu(struct efx_nic *efx)
+{
+       /* The maximum MTU that we can fit in a single page, allowing for
+        * framing, overhead and XDP headroom.
+        */
+       int overhead = EFX_MAX_FRAME_LEN(0) + sizeof(struct efx_rx_page_state) +
+                      efx->rx_prefix_size + efx->type->rx_buffer_padding +
+                      efx->rx_ip_align + XDP_PACKET_HEADROOM;
+
+       return PAGE_SIZE - overhead;
+}
 
 /* Context: process, rtnl_lock() held. */
 static int efx_change_mtu(struct net_device *net_dev, int new_mtu)
@@ -2291,6 +2308,14 @@ static int efx_change_mtu(struct net_device *net_dev, int new_mtu)
        if (rc)
                return rc;
 
+       if (rtnl_dereference(efx->xdp_prog) &&
+           new_mtu > efx_xdp_max_mtu(efx)) {
+               netif_err(efx, drv, efx->net_dev,
+                         "Requested MTU of %d too big for XDP (max: %d)\n",
+                         new_mtu, efx_xdp_max_mtu(efx));
+               return -EINVAL;
+       }
+
        netif_dbg(efx, drv, efx->net_dev, "changing MTU to %d\n", new_mtu);
 
        efx_device_detach_sync(efx);
@@ -2492,8 +2517,53 @@ static const struct net_device_ops efx_netdev_ops = {
 #endif
        .ndo_udp_tunnel_add     = efx_udp_tunnel_add,
        .ndo_udp_tunnel_del     = efx_udp_tunnel_del,
+       .ndo_bpf                = efx_xdp
 };
 
+static int efx_xdp_setup_prog(struct efx_nic *efx, struct bpf_prog *prog)
+{
+       struct bpf_prog *old_prog;
+
+       if (efx->xdp_rxq_info_failed) {
+               netif_err(efx, drv, efx->net_dev,
+                         "Unable to bind XDP program due to previous failure of rxq_info\n");
+               return -EINVAL;
+       }
+
+       if (prog && efx->net_dev->mtu > efx_xdp_max_mtu(efx)) {
+               netif_err(efx, drv, efx->net_dev,
+                         "Unable to configure XDP with MTU of %d (max: %d)\n",
+                         efx->net_dev->mtu, efx_xdp_max_mtu(efx));
+               return -EINVAL;
+       }
+
+       old_prog = rtnl_dereference(efx->xdp_prog);
+       rcu_assign_pointer(efx->xdp_prog, prog);
+       /* Release the reference that was originally passed by the caller. */
+       if (old_prog)
+               bpf_prog_put(old_prog);
+
+       return 0;
+}
+
+/* Context: process, rtnl_lock() held. */
+static int efx_xdp(struct net_device *dev, struct netdev_bpf *xdp)
+{
+       struct efx_nic *efx = netdev_priv(dev);
+       struct bpf_prog *xdp_prog;
+
+       switch (xdp->command) {
+       case XDP_SETUP_PROG:
+               return efx_xdp_setup_prog(efx, xdp->prog);
+       case XDP_QUERY_PROG:
+               xdp_prog = rtnl_dereference(efx->xdp_prog);
+               xdp->prog_id = xdp_prog ? xdp_prog->aux->id : 0;
+               return 0;
+       default:
+               return -EINVAL;
+       }
+}
+
 static void efx_update_name(struct efx_nic *efx)
 {
        strcpy(efx->name, efx->net_dev->name);