Allow increasing the MTU over page boundaries on veth devices
if the attached xdp program declares to support xdp fragments.
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
drivers/net/veth.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index bfae15ec902b..1b5714926d81 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1528,9 +1528,14 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
goto err;
}
- max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
- peer->hard_header_len -
- SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
+ peer->hard_header_len;
+ /* Allow increasing the max_mtu if the program supports
+ * XDP fragments.
+ */
+ if (prog->aux->xdp_has_frags)
+ max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
+
if (peer->mtu > max_mtu) {
NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
err = -ERANGE;
--
2.35.1
