[PATCH net v8 2/2] net: stmmac: remove software VLAN tag stripping
From: <hidden>
Date: 2026-09-19 12:59:13
Also in:
linux-arm-kernel, lkml
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
From: Peilin He <redacted>
The software VLAN stripping logic in stmmac_rx_vlan() was originally
introduced in 2014 by commit b93819854d6e ("stmmac: Add vlan rx for
better GRO performance.") as a workaround to improve GRO performance,
since at that time GRO could not handle frames with VLAN tags. However,
this limitation was resolved in 2015 by commit 66e5133f19e9 ("vlan: Add
GRO support for non hardware accelerated vlan"), which added GRO support
for non-hardware-accelerated VLAN frames. Keeping a software fallback
path for VLAN stripping is no longer necessary and only adds complexity.
After removing it, VLAN tags remain in the packet. Adjust
stmmac_has_ip_ethertype() to tolerate a single in-payload VLAN tag so
that the MAC RX checksum offload result is still used for tagged
IPv4/IPv6 frames on cores without MAC-level stripping.
This intentionally changes the advertised features:
- dwmac100/dwmac1000 no longer advertise NETIF_F_HW_VLAN_CTAG_RX;
they have no hardware VLAN stripping.
- NETIF_F_HW_VLAN_STAG_RX is no longer advertised, as the hardware
reports stripped S-tags as C-tags.
- On xmac cores NETIF_F_HW_VLAN_CTAG_RX is advertised only when the
VLAN ops provide .set_hw_vlan_mode and .rx_hw_vlan, so DWXLGMAC no
longer falsely advertises RX VLAN offload.
With NETIF_F_VLAN_FEATURES possibly empty, EEE RX clock stop may be
enabled on some platforms; the preceding selftests patch blocks RX
clock stop while the ethtool selftests run.
This depends on the preceding selftests fix.
Suggested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Peilin He <redacted>
Reviewed-by: xu xin <redacted>
Reviewed-by: Jiang Kun <redacted>
---
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 38 +++++--------------
1 file changed, 10 insertions(+), 28 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 9c9e95d66b09..6d4716b1a7ad 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c@@ -4752,7 +4752,11 @@ static bool stmmac_has_ip_ethertype(struct sk_buff *skb) proto = __vlan_get_protocol(skb, eth_header_parse_protocol(skb), &depth); - return (depth <= ETH_HLEN) && + /* Software VLAN stripping is gone, so a single VLAN tag may + * still be present. The MAC RX checksum result still applies + * to the inner IP packet. + */ + return (depth <= VLAN_ETH_HLEN) && (proto == htons(ETH_P_IP) || proto == htons(ETH_P_IPV6)); }
@@ -5032,24 +5036,6 @@ static netdev_features_t stmmac_features_check(struct sk_buff *skb, return vlan_features_check(skb, features); } -static void stmmac_rx_vlan(struct net_device *dev, struct sk_buff *skb) -{ - struct vlan_ethhdr *veth = skb_vlan_eth_hdr(skb); - __be16 vlan_proto = veth->h_vlan_proto; - u16 vlanid; - - if ((vlan_proto == htons(ETH_P_8021Q) && - dev->features & NETIF_F_HW_VLAN_CTAG_RX) || - (vlan_proto == htons(ETH_P_8021AD) && - dev->features & NETIF_F_HW_VLAN_STAG_RX)) { - /* pop the vlan tag */ - vlanid = ntohs(veth->h_vlan_TCI); - memmove(skb->data + VLAN_HLEN, veth, ETH_ALEN * 2); - skb_pull(skb, VLAN_HLEN); - __vlan_hwaccel_put_tag(skb, vlan_proto, vlanid); - } -} - /** * stmmac_rx_refill - refill used skb preallocated buffers * @priv: driver private structure
@@ -5418,9 +5404,7 @@ static void stmmac_dispatch_skb_zc(struct stmmac_priv *priv, u32 queue, if (priv->hw->hw_vlan_en) /* MAC level stripping. */ stmmac_rx_hw_vlan(priv, priv->hw, p, skb); - else - /* Driver level stripping. */ - stmmac_rx_vlan(priv->dev, skb); + skb->protocol = eth_type_trans(skb, priv->dev); if (unlikely(!coe) || !stmmac_has_ip_ethertype(skb))
@@ -5912,9 +5896,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) if (priv->hw->hw_vlan_en) /* MAC level stripping. */ stmmac_rx_hw_vlan(priv, priv->hw, p, skb); - else - /* Driver level stripping. */ - stmmac_rx_vlan(priv->dev, skb); skb->protocol = eth_type_trans(skb, priv->dev);
@@ -7995,9 +7976,10 @@ static int __stmmac_dvr_probe(struct device *device, ndev->features |= ndev->hw_features | NETIF_F_HIGHDMA; ndev->watchdog_timeo = msecs_to_jiffies(watchdog); #ifdef STMMAC_VLAN_TAG_USED - /* Both mac100 and gmac support receive VLAN tag detection */ - ndev->features |= NETIF_F_HW_VLAN_CTAG_RX | NETIF_F_HW_VLAN_STAG_RX; - if (dwmac_is_xmac(priv->plat->core_type)) { + if (priv->hw->vlan && + priv->hw->vlan->set_hw_vlan_mode && + priv->hw->vlan->rx_hw_vlan) { + ndev->features |= NETIF_F_HW_VLAN_CTAG_RX; ndev->hw_features |= NETIF_F_HW_VLAN_CTAG_RX; priv->hw->hw_vlan_en = true; }
--
2.43.0