[PATCH 5.15 124/179] net: marvell: mvpp2: increase MTU limit when XDP enabled

From: Greg Kroah-Hartman
Date: Mon Nov 29 2021 - 13:43:02 EST


From: Marek Behún <kabel@xxxxxxxxxx>

[ Upstream commit 7b1b62bc1e6a7b2fd5ee7a4296268eb291d23aeb ]

Currently mvpp2_xdp_setup won't allow attaching XDP program if
mtu > ETH_DATA_LEN (1500).

The mvpp2_change_mtu on the other hand checks whether
MVPP2_RX_PKT_SIZE(mtu) > MVPP2_BM_LONG_PKT_SIZE.

These two checks are semantically different.

Moreover this limit can be increased to MVPP2_MAX_RX_BUF_SIZE, since in
mvpp2_rx we have
xdp.data = data + MVPP2_MH_SIZE + MVPP2_SKB_HEADROOM;
xdp.frame_sz = PAGE_SIZE;

Change the checks to check whether
mtu > MVPP2_MAX_RX_BUF_SIZE

Fixes: 07dd0a7aae7f ("mvpp2: add basic XDP support")
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index d74d4966b13fc..ed6d0c019573b 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -5017,11 +5017,13 @@ static int mvpp2_change_mtu(struct net_device *dev, int mtu)
mtu = ALIGN(MVPP2_RX_PKT_SIZE(mtu), 8);
}

+ if (port->xdp_prog && mtu > MVPP2_MAX_RX_BUF_SIZE) {
+ netdev_err(dev, "Illegal MTU value %d (> %d) for XDP mode\n",
+ mtu, (int)MVPP2_MAX_RX_BUF_SIZE);
+ return -EINVAL;
+ }
+
if (MVPP2_RX_PKT_SIZE(mtu) > MVPP2_BM_LONG_PKT_SIZE) {
- if (port->xdp_prog) {
- netdev_err(dev, "Jumbo frames are not supported with XDP\n");
- return -EINVAL;
- }
if (priv->percpu_pools) {
netdev_warn(dev, "mtu %d too high, switching to shared buffers", mtu);
mvpp2_bm_switch_buffers(priv, false);
@@ -5307,8 +5309,8 @@ static int mvpp2_xdp_setup(struct mvpp2_port *port, struct netdev_bpf *bpf)
bool running = netif_running(port->dev);
bool reset = !prog != !port->xdp_prog;

- if (port->dev->mtu > ETH_DATA_LEN) {
- NL_SET_ERR_MSG_MOD(bpf->extack, "XDP is not supported with jumbo frames enabled");
+ if (port->dev->mtu > MVPP2_MAX_RX_BUF_SIZE) {
+ NL_SET_ERR_MSG_MOD(bpf->extack, "MTU too large for XDP");
return -EOPNOTSUPP;
}

--
2.33.0