RE: [PATCH net-next v5 1/2] net: mana: Handle SKB if TX SGEs exceed hardware limit

[Haiyang Zhang]

> -----Original Message-----
> From: Aditya Garg <gargaditya@xxxxxxxxxxxxxxxxxxx>
> Sent: Friday, November 14, 2025 4:17 PM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; wei.liu@xxxxxxxxxx; Dexuan Cui
> <DECUI@xxxxxxxxxxxxx>; andrew+netdev@xxxxxxx; davem@xxxxxxxxxxxxx;
> edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; Long Li
> <longli@xxxxxxxxxxxxx>; Konstantin Taranov <kotaranov@xxxxxxxxxxxxx>;
> horms@xxxxxxxxxx; shradhagupta@xxxxxxxxxxxxxxxxxxx;
> ssengar@xxxxxxxxxxxxxxxxxxx; ernis@xxxxxxxxxxxxxxxxxxx;
> dipayanroy@xxxxxxxxxxxxxxxxxxx; Shiraz Saleem
> <shirazsaleem@xxxxxxxxxxxxx>; leon@xxxxxxxxxx; mlevitsk@xxxxxxxxxx;
> yury.norov@xxxxxxxxx; sbhatta@xxxxxxxxxxx; linux-hyperv@xxxxxxxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> rdma@xxxxxxxxxxxxxxx; Aditya Garg <gargaditya@xxxxxxxxxxxxx>
> Cc: Aditya Garg <gargaditya@xxxxxxxxxxxxxxxxxxx>
> Subject: [PATCH net-next v5 1/2] net: mana: Handle SKB if TX SGEs exceed
> hardware limit
> 
> The MANA hardware supports a maximum of 30 scatter-gather entries (SGEs)
> per TX WQE. Exceeding this limit can cause TX failures.
> Add ndo_features_check() callback to validate SKB layout before
> transmission. For GSO SKBs that would exceed the hardware SGE limit, clear
> NETIF_F_GSO_MASK to enforce software segmentation in the stack.
> Add a fallback in mana_start_xmit() to linearize non-GSO SKBs that still
> exceed the SGE limit.
> 
> Also, Add ethtool counter for SKBs linearized
> 
> Co-developed-by: Dipayaan Roy <dipayanroy@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Dipayaan Roy <dipayanroy@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Aditya Garg <gargaditya@xxxxxxxxxxxxxxxxxxx>

Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>