* [PATCH net v2] net: stmmac: keep gso_enabled_types in sync with netdev features
@ 2026-08-12 4:38 Lorenzo Bianconi
2026-08-12 7:30 ` Maxime Chevallier
0 siblings, 1 reply; 2+ messages in thread
From: Lorenzo Bianconi @ 2026-08-12 4:38 UTC (permalink / raw)
To: Maxime Chevallier, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Maxime Coquelin, Alexandre Torgue,
Russell King (Oracle)
Cc: netdev, linux-stm32, linux-arm-kernel, Lorenzo Bianconi
stmmac_set_gso_types() derives priv->gso_enabled_types all-or-nothing
from NETIF_F_TSO, but stmmac_set_gso_features() advertises NETIF_F_TSO,
NETIF_F_TSO6 and (on GMAC4) NETIF_F_GSO_UDP_L4 as independently
toggleable features. Since netdev_fix_features() only ties TSO6 to the
checksum features, disabling TSO (ethtool -K ethX tx-tcp-segmentation
off) leaves TSO6 enabled in dev->features while gso_enabled_types
becomes 0.
For a TCPv6 GSO skb the stack then keeps the frame unsegmented
(NETIF_F_TSO6 is still set), stmmac_features_check() does not clear the
GSO mask, and the stmmac_xmit() gate (gso_type & gso_enabled_types) is
false, so the multi-MSS skb is transmitted through the ordinary
descriptor path as a single oversized frame.
Derive each GSO type from its own feature bit instead, so the mask stays
in sync with dev->features and TCPv6 (or UDP L4 on GMAC4) segmentation
keeps working when only TSO is disabled.
Fixes: 9edfa7dab811 ("net: stmmac: enable TSO for IPv6")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
---
Changes in v2:
- Fix possible race between stmmac_set_gso_types() and stmmac_xmit().
- Fix fixes tag.
- Link to v1: https://lore.kernel.org/r/20260808-stmmac-fix-tso6-features-v1-1-f82b17595052@oss.qualcomm.com
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 28 +++++++++++++----------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index a71f0df26378..df3549f55741 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4371,16 +4371,20 @@ static void stmmac_flush_tx_descriptors(struct stmmac_priv *priv, int queue)
stmmac_set_queue_tx_tail_ptr(priv, tx_q, queue, tx_q->cur_tx);
}
-static void stmmac_set_gso_types(struct stmmac_priv *priv, bool tso)
+static void stmmac_set_gso_types(struct stmmac_priv *priv,
+ netdev_features_t features)
{
- if (!tso) {
- priv->gso_enabled_types = 0;
- } else {
- /* Manage oversized TCP frames for GMAC4 device */
- priv->gso_enabled_types = SKB_GSO_TCPV4 | SKB_GSO_TCPV6;
- if (priv->plat->core_type == DWMAC_CORE_GMAC4)
- priv->gso_enabled_types |= SKB_GSO_UDP_L4;
- }
+ unsigned int gso_types = 0;
+
+ if (features & NETIF_F_TSO)
+ gso_types |= SKB_GSO_TCPV4;
+ if (features & NETIF_F_TSO6)
+ gso_types |= SKB_GSO_TCPV6;
+ /* Manage oversized UDP frames for GMAC4 devices */
+ if (features & NETIF_F_GSO_UDP_L4)
+ gso_types |= SKB_GSO_UDP_L4;
+
+ WRITE_ONCE(priv->gso_enabled_types, gso_types);
}
static void stmmac_set_gso_features(struct net_device *ndev)
@@ -4416,7 +4420,7 @@ static void stmmac_set_gso_features(struct net_device *ndev)
if (priv->plat->core_type == DWMAC_CORE_GMAC4)
ndev->hw_features |= NETIF_F_GSO_UDP_L4;
- stmmac_set_gso_types(priv, true);
+ stmmac_set_gso_types(priv, ndev->hw_features);
dev_info(priv->device, "TSO feature enabled\n");
}
@@ -4766,7 +4770,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
stmmac_stop_sw_lpi(priv);
if (skb_is_gso(skb) &&
- skb_shinfo(skb)->gso_type & priv->gso_enabled_types)
+ (skb_shinfo(skb)->gso_type & READ_ONCE(priv->gso_enabled_types)))
return stmmac_tso_xmit(skb, dev);
if (priv->est && priv->est->enable &&
@@ -6198,7 +6202,7 @@ static int stmmac_set_features(struct net_device *netdev,
stmmac_enable_sph(priv, priv->ioaddr, sph_en, chan);
}
- stmmac_set_gso_types(priv, features & NETIF_F_TSO);
+ stmmac_set_gso_types(priv, features);
if (features & NETIF_F_HW_VLAN_CTAG_RX)
priv->hw->hw_vlan_en = true;
---
base-commit: 7b53449540502cb21b32bca62a6258e22cd97bbe
change-id: 20260808-stmmac-fix-tso6-features-7fdc5e9448e2
Best regards,
--
Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net v2] net: stmmac: keep gso_enabled_types in sync with netdev features
2026-08-12 4:38 [PATCH net v2] net: stmmac: keep gso_enabled_types in sync with netdev features Lorenzo Bianconi
@ 2026-08-12 7:30 ` Maxime Chevallier
0 siblings, 0 replies; 2+ messages in thread
From: Maxime Chevallier @ 2026-08-12 7:30 UTC (permalink / raw)
To: Lorenzo Bianconi, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Maxime Coquelin, Alexandre Torgue,
Russell King (Oracle)
Cc: netdev, linux-stm32, linux-arm-kernel
Hi Lorenzo,
On 8/12/26 06:38, Lorenzo Bianconi wrote:
> stmmac_set_gso_types() derives priv->gso_enabled_types all-or-nothing
> from NETIF_F_TSO, but stmmac_set_gso_features() advertises NETIF_F_TSO,
> NETIF_F_TSO6 and (on GMAC4) NETIF_F_GSO_UDP_L4 as independently
> toggleable features. Since netdev_fix_features() only ties TSO6 to the
> checksum features, disabling TSO (ethtool -K ethX tx-tcp-segmentation
> off) leaves TSO6 enabled in dev->features while gso_enabled_types
> becomes 0.
>
> For a TCPv6 GSO skb the stack then keeps the frame unsegmented
> (NETIF_F_TSO6 is still set), stmmac_features_check() does not clear the
> GSO mask, and the stmmac_xmit() gate (gso_type & gso_enabled_types) is
> false, so the multi-MSS skb is transmitted through the ordinary
> descriptor path as a single oversized frame.
>
> Derive each GSO type from its own feature bit instead, so the mask stays
> in sync with dev->features and TCPv6 (or UDP L4 on GMAC4) segmentation
> keeps working when only TSO is disabled.
>
> Fixes: 9edfa7dab811 ("net: stmmac: enable TSO for IPv6")
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Maxime
> ---
> Changes in v2:
> - Fix possible race between stmmac_set_gso_types() and stmmac_xmit().
> - Fix fixes tag.
> - Link to v1: https://lore.kernel.org/r/20260808-stmmac-fix-tso6-features-v1-1-f82b17595052@oss.qualcomm.com
> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 28 +++++++++++++----------
> 1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index a71f0df26378..df3549f55741 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -4371,16 +4371,20 @@ static void stmmac_flush_tx_descriptors(struct stmmac_priv *priv, int queue)
> stmmac_set_queue_tx_tail_ptr(priv, tx_q, queue, tx_q->cur_tx);
> }
>
> -static void stmmac_set_gso_types(struct stmmac_priv *priv, bool tso)
> +static void stmmac_set_gso_types(struct stmmac_priv *priv,
> + netdev_features_t features)
> {
> - if (!tso) {
> - priv->gso_enabled_types = 0;
> - } else {
> - /* Manage oversized TCP frames for GMAC4 device */
> - priv->gso_enabled_types = SKB_GSO_TCPV4 | SKB_GSO_TCPV6;
> - if (priv->plat->core_type == DWMAC_CORE_GMAC4)
> - priv->gso_enabled_types |= SKB_GSO_UDP_L4;
> - }
> + unsigned int gso_types = 0;
> +
> + if (features & NETIF_F_TSO)
> + gso_types |= SKB_GSO_TCPV4;
> + if (features & NETIF_F_TSO6)
> + gso_types |= SKB_GSO_TCPV6;
> + /* Manage oversized UDP frames for GMAC4 devices */
> + if (features & NETIF_F_GSO_UDP_L4)
> + gso_types |= SKB_GSO_UDP_L4;
> +
> + WRITE_ONCE(priv->gso_enabled_types, gso_types);
> }
>
> static void stmmac_set_gso_features(struct net_device *ndev)
> @@ -4416,7 +4420,7 @@ static void stmmac_set_gso_features(struct net_device *ndev)
> if (priv->plat->core_type == DWMAC_CORE_GMAC4)
> ndev->hw_features |= NETIF_F_GSO_UDP_L4;
>
> - stmmac_set_gso_types(priv, true);
> + stmmac_set_gso_types(priv, ndev->hw_features);
>
> dev_info(priv->device, "TSO feature enabled\n");
> }
> @@ -4766,7 +4770,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
> stmmac_stop_sw_lpi(priv);
>
> if (skb_is_gso(skb) &&
> - skb_shinfo(skb)->gso_type & priv->gso_enabled_types)
> + (skb_shinfo(skb)->gso_type & READ_ONCE(priv->gso_enabled_types)))
> return stmmac_tso_xmit(skb, dev);
>
> if (priv->est && priv->est->enable &&
> @@ -6198,7 +6202,7 @@ static int stmmac_set_features(struct net_device *netdev,
> stmmac_enable_sph(priv, priv->ioaddr, sph_en, chan);
> }
>
> - stmmac_set_gso_types(priv, features & NETIF_F_TSO);
> + stmmac_set_gso_types(priv, features);
>
> if (features & NETIF_F_HW_VLAN_CTAG_RX)
> priv->hw->hw_vlan_en = true;
>
> ---
> base-commit: 7b53449540502cb21b32bca62a6258e22cd97bbe
> change-id: 20260808-stmmac-fix-tso6-features-7fdc5e9448e2
>
> Best regards,
^ permalink raw reply [flat|nested] 2+ messages in thread
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