[PATCH v2] net/af_packet: add multi-segment mbuf support for jumbo frames

[Sriram Yagnaraman]

> -----Original Message-----
> From: Stephen Hemminger <stephen at networkplumber.org>
> Sent: Tuesday, 10 March 2026 15:03
> To: Sriram Yagnaraman <sriram.yagnaraman at ericsson.com>
> Cc: dev at dpdk.org; xavier.guillaume at ovhcloud.com
> Subject: Re: [PATCH v2] net/af_packet: add multi-segment mbuf support for
> jumbo frames
> 
> On Mon, 9 Mar 2026 22:02:10 +0100
> Sriram Yagnaraman <sriram.yagnaraman at ericsson.com> wrote:
> 
> > Enable jumbo frame reception with default mbuf data room size by
> > chaining multiple mbufs when packet exceeds single mbuf tailroom.
> >
> > The RX path now:
> > - Copies first segment up to mbuf tailroom
> > - Allocates and chains additional segments for remaining data
> > - Properly maintains nb_segs, next pointers, and pkt_len
> > - Silently drops packets on mbuf allocation failure
> >
> > This allows receiving 9KB jumbo frames using standard 2KB mbufs,
> > chaining ~5 segments per jumbo packet. No need for custom mbuf pools
> > with large data room.
> >
> > Advertises RTE_ETH_RX_OFFLOAD_SCATTER capability.
> >
> > Depends-on: series-34567 ("net/af_packet: fix MTU handling and add
> > jumbo frame support")
> >
> > Note: Implementation generated with AI assistance.
> >
> > Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman at ericsson.com>
> 
> Using AI patch review finds several issues.

Thanks for the review, I will fix them in v3.
Perhaps, I will wait for Xavier's changes to be in main before posting the next version.