From cc9dcb0e7a428ca43259bbee3350d786681265a3 Mon Sep 17 00:00:00 2001 From: Wang Zhan Date: Thu, 8 Oct 2026 18:06:46 +0800 Subject: [PATCH] net: core: use the packet's L3 protocol for the GSO size limit gso_features_check() compares the frame length against netif_get_gso_max_size(), which picks the IPv4 or the IPv6 limit from skb->protocol. A tag which is already inside the frame replaces that field with the VLAN ethertype, as skb_vlan_push() does, and an IPv6 packet is then measured against the IPv4 limit and segmented although the device could send it as one TSO frame. The lookup moves from netdevice.h into dev.c: vlan_get_protocol() reads the L3 protocol from behind an in-frame tag, while if_vlan.h includes netdevice.h, so an inline in that header cannot call it. dev.c is the only file which calls the lookup, so it becomes a static helper there. Reviewed-by: Willem de Bruijn Assisted-by: LLM Signed-off-by: Wang Zhan Link: https://patch.msgid.link/20261008100651.2534957-2-wang.zhan@smartx.com Signed-off-by: Paolo Abeni --- include/linux/netdevice.h | 9 --------- net/core/dev.c | 9 +++++++++ 2 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 5b4b92e76b67..1743dcd02d5b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -5566,15 +5566,6 @@ netif_get_gro_max_size(const struct net_device *dev, const struct sk_buff *skb) READ_ONCE(dev->gro_ipv4_max_size); } -static inline unsigned int -netif_get_gso_max_size(const struct net_device *dev, const struct sk_buff *skb) -{ - /* pairs with WRITE_ONCE() in netif_set_gso(_ipv4)_max_size() */ - return skb->protocol == htons(ETH_P_IPV6) ? - READ_ONCE(dev->gso_max_size) : - READ_ONCE(dev->gso_ipv4_max_size); -} - static inline bool netif_is_macsec(const struct net_device *dev) { return dev->priv_flags & IFF_MACSEC; diff --git a/net/core/dev.c b/net/core/dev.c index a6951ea08961..df7ec4faaa81 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3888,6 +3888,15 @@ static bool skb_has_ipv6_extension_hdr(const struct sk_buff *skb) return false; } +static unsigned int +netif_get_gso_max_size(const struct net_device *dev, const struct sk_buff *skb) +{ + /* pairs with WRITE_ONCE() in netif_set_gso(_ipv4)_max_size() */ + return vlan_get_protocol(skb) == htons(ETH_P_IPV6) ? + READ_ONCE(dev->gso_max_size) : + READ_ONCE(dev->gso_ipv4_max_size); +} + static netdev_features_t gso_features_check(const struct sk_buff *skb, struct net_device *dev, netdev_features_t features)