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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Zak Kemble , Simon Horman , Ryo Takakura , open list , Nicolai Buchwitz References: <20261008210621.1374785-1-florian.fainelli@broadcom.com> <20261008210621.1374785-6-florian.fainelli@broadcom.com> Content-Language: en-US From: Justin Chen In-Reply-To: <20261008210621.1374785-6-florian.fainelli@broadcom.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e On 10/8/26 2:06 PM, Florian Fainelli wrote: > When hardware checksum offload is enabled for an skb, > bcmasp_csum_offload() prepends a struct bcmasp_pkt_offload header > (20 bytes) to the skb via skb_push(). This increases skb->len and > skb_headlen(skb) by sizeof(struct bcmasp_pkt_offload). > > Because the hardware descriptor processor strips this offload header > before transmitting the packet on the wire, the wire packet length is > smaller by sizeof(struct bcmasp_pkt_offload). The padding calculation > must account for this extra header; otherwise, short frames are sent on > the wire smaller than the minimum Ethernet frame size (ETH_ZLEN + > ETH_FCS_LEN). > > Furthermore, small frames with payload in page fragments (such as small > TCP segments with CHECKSUM_PARTIAL) have nr_frags > 0 and were skipping > padding entirely because the padding check was restricted to > nr_frags == 0. > > Perform the padding check on skb->len before the descriptor loop using > skb_put_padto(), adding sizeof(struct bcmasp_pkt_offload) to min_size > when checksum offload is enabled, and re-read nr_frags after padding in > case the skb was linearized. > > Fixes: 490cb412007d ("net: bcmasp: Add support for ASP2.0 Ethernet controller") > Assisted-by: LLM > Signed-off-by: Florian Fainelli Reviewed-by: Justin Chen