* [PATCH net-next] net: bgmac: stop advertising TX checksum offload
@ 2026-11-02 21:58 Rosen Penev
2026-11-03 9:26 ` Markus Elfring
0 siblings, 1 reply; 2+ messages in thread
From: Rosen Penev @ 2026-11-02 21:58 UTC (permalink / raw)
To: netdev
Cc: Rafał Miłecki, Broadcom internal kernel review list,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, open list
The driver advertises NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM, but
bgmac_dma_tx_add() calls skb_checksum_help() on every CHECKSUM_PARTIAL
skb, so the checksum is always computed in software anyway. The return
value is ignored too, so if skb_checksum_help() fails the frame is sent
with a bad checksum.
Remove the feature flags and the fallback. The stack then computes the
checksum before handing the skb to the driver.
Tested on an ASUS RT-N16.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
drivers/net/ethernet/broadcom/bgmac.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 2dff43f540d3..822903a3ac6e 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -145,9 +145,6 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
goto err_drop;
}
- if (skb->ip_summed == CHECKSUM_PARTIAL)
- skb_checksum_help(skb);
-
nr_frags = skb_shinfo(skb)->nr_frags;
/* ring->end - ring->start will return the number of valid slots,
@@ -1574,7 +1571,7 @@ int bgmac_enet_probe(struct bgmac *bgmac)
goto err_dma_free;
}
- net_dev->features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
+ net_dev->features = NETIF_F_SG;
net_dev->hw_features = net_dev->features;
net_dev->vlan_features = net_dev->features;
--
2.56.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] net: bgmac: stop advertising TX checksum offload
2026-11-02 21:58 [PATCH net-next] net: bgmac: stop advertising TX checksum offload Rosen Penev
@ 2026-11-03 9:26 ` Markus Elfring
0 siblings, 0 replies; 2+ messages in thread
From: Markus Elfring @ 2026-11-03 9:26 UTC (permalink / raw)
To: Rosen Penev, netdev, bcm-kernel-feedback-list
Cc: linux-kernel, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Rafał Miłecki
…
> Remove the feature flags and the fallback. The stack then computes the
> checksum before handing the skb to the driver.
…
How can a “stack” compute anything?
Regards,
Markus
^ permalink raw reply [flat|nested] 2+ messages in thread
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