dpaa2-eth: Allow XDP header adjustments

Reserve XDP_PACKET_HEADROOM bytes in Rx buffers to allow XDP
programs to increase frame header size.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index d3cfed4..008cdf8 100644 (file)
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -216,11 +216,15 @@ static u32 run_xdp(struct dpaa2_eth_priv *priv,
 
        xdp.data = vaddr + dpaa2_fd_get_offset(fd);
        xdp.data_end = xdp.data + dpaa2_fd_get_len(fd);
-       xdp.data_hard_start = xdp.data;
+       xdp.data_hard_start = xdp.data - XDP_PACKET_HEADROOM;
        xdp_set_data_meta_invalid(&xdp);
 
        xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
 
+       /* xdp.data pointer may have changed */
+       dpaa2_fd_set_offset(fd, xdp.data - vaddr);
+       dpaa2_fd_set_len(fd, xdp.data_end - xdp.data);
+
        switch (xdp_act) {
        case XDP_PASS:
                break;
@@ -1483,7 +1487,7 @@ static bool xdp_mtu_valid(struct dpaa2_eth_priv *priv, int mtu)
 
        mfl = DPAA2_ETH_L2_MAX_FRM(mtu);
        linear_mfl = DPAA2_ETH_RX_BUF_SIZE - DPAA2_ETH_RX_HWA_SIZE -
-                    dpaa2_eth_rx_head_room(priv);
+                    dpaa2_eth_rx_head_room(priv) - XDP_PACKET_HEADROOM;
 
        if (mfl > linear_mfl) {
                netdev_warn(priv->net_dev, "Maximum MTU for XDP is %d\n",
@@ -1537,6 +1541,32 @@ out:
        return 0;
 }
 
+static int update_rx_buffer_headroom(struct dpaa2_eth_priv *priv, bool has_xdp)
+{
+       struct dpni_buffer_layout buf_layout = {0};
+       int err;
+
+       err = dpni_get_buffer_layout(priv->mc_io, 0, priv->mc_token,
+                                    DPNI_QUEUE_RX, &buf_layout);
+       if (err) {
+               netdev_err(priv->net_dev, "dpni_get_buffer_layout failed\n");
+               return err;
+       }
+
+       /* Reserve extra headroom for XDP header size changes */
+       buf_layout.data_head_room = dpaa2_eth_rx_head_room(priv) +
+                                   (has_xdp ? XDP_PACKET_HEADROOM : 0);
+       buf_layout.options = DPNI_BUF_LAYOUT_OPT_DATA_HEAD_ROOM;
+       err = dpni_set_buffer_layout(priv->mc_io, 0, priv->mc_token,
+                                    DPNI_QUEUE_RX, &buf_layout);
+       if (err) {
+               netdev_err(priv->net_dev, "dpni_set_buffer_layout failed\n");
+               return err;
+       }
+
+       return 0;
+}
+
 static int setup_xdp(struct net_device *dev, struct bpf_prog *prog)
 {
        struct dpaa2_eth_priv *priv = netdev_priv(dev);
@@ -1560,11 +1590,18 @@ static int setup_xdp(struct net_device *dev, struct bpf_prog *prog)
        if (up)
                dpaa2_eth_stop(dev);
 
-       /* While in xdp mode, enforce a maximum Rx frame size based on MTU */
+       /* While in xdp mode, enforce a maximum Rx frame size based on MTU.
+        * Also, when switching between xdp/non-xdp modes we need to reconfigure
+        * our Rx buffer layout. Buffer pool was drained on dpaa2_eth_stop,
+        * so we are sure no old format buffers will be used from now on.
+        */
        if (need_update) {
                err = set_rx_mfl(priv, dev->mtu, !!prog);
                if (err)
                        goto out_err;
+               err = update_rx_buffer_headroom(priv, !!prog);
+               if (err)
+                       goto out_err;
        }
 
        old = xchg(&priv->xdp_prog, prog);