Re: [PATCH net-next v5 11/19] xdp: add generic xdp_buff_add_frag()

[Ido Schimmel]

On Wed, Nov 13, 2024 at 04:24:34PM +0100, Alexander Lobakin wrote:
> The code piece which would attach a frag to &xdp_buff is almost
> identical across the drivers supporting XDP multi-buffer on Rx.

Yes, I was reviewing such a change when I noticed your patch. We will
use this helper instead. Thanks!

> Make it a generic elegant "oneliner".
> Also, I see lots of drivers calculating frags_truesize as
> `xdp->frame_sz * nr_frags`. I can't say this is fully correct, since
> frags might be backed by chunks of different sizes, especially with
> stuff like the header split. Even page_pool_alloc() can give you two
> different truesizes on two subsequent requests to allocate the same
> buffer size. Add a field to &skb_shared_info (unionized as there's no
> free slot currently on x86_64) to track the "true" truesize. It can
> be used later when updating an skb.
> 
> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>

Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx>