netdev - Re: [PATCH bpf-next v2 3/7] bpf: Support pulling non-linear xdp data

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Message-ID: <CAMB2axP=fUpeCnKGRCJtqU9cdrtv6M9WDFUMjpmFvEZdj_+g2A@mail.gmail.com>
Date: Mon, 8 Sep 2025 15:28:05 -0700
From: Amery Hung <ameryhung@...il.com>
To: Martin KaFai Lau <martin.lau@...ux.dev>
Cc: bpf@...r.kernel.org, netdev@...r.kernel.org, alexei.starovoitov@...il.com, 
	andrii@...nel.org, daniel@...earbox.net, kuba@...nel.org, 
	stfomichev@...il.com, martin.lau@...nel.org, mohsin.bashr@...il.com, 
	noren@...dia.com, dtatulea@...dia.com, saeedm@...dia.com, tariqt@...dia.com, 
	mbloch@...dia.com, maciej.fijalkowski@...el.com, kernel-team@...a.com
Subject: Re: [PATCH bpf-next v2 3/7] bpf: Support pulling non-linear xdp data

On Mon, Sep 8, 2025 at 12:27 PM Martin KaFai Lau <martin.lau@...ux.dev> wrote:
>
> On 9/5/25 10:33 AM, Amery Hung wrote:
> > An unused argument, flags is reserved for future extension (e.g.,
> > tossing the data instead of copying it to the linear data area).
>
> > +__bpf_kfunc int bpf_xdp_pull_data(struct xdp_md *x, u32 len, u64 flags)
>
> I was thinking the flag may be needed to avoid copy. I think we have recently
> concluded that bpf_xdp_adjust_head can support shrink on multi buf also. If it
> is the case, it is probably better to keep a similar api as the
> bpf_skb_pull_data which does not have the flags argument.
>

Make sense. I will remove flags.