Re: [PATCH net-next v1 07/11] xsk: Deliver provider chunks without copying

["Björn Töpel" <bjorn@kernel.org>]

netdev-bot+sashiko@kernel.org writes:

> Should this be gated by a flag? Or should the commit message describe it
> as a UAPI change rather than as a device property?

Neither, it isn't a UAPI change. The headroom text predates
multi-buffer, when a buffer held a whole packet: "the packet will start
N bytes into the buffer". A continuation buffer doesn't start a packet,
and the room in front of the packet, for headers or metadata, is still
there in its first buffer. Userspace reads each buffer at the address in
its descriptor anyway; XDP can already move the start with
bpf_xdp_adjust_head(). The doc change only spells out a valid
multi-buffer variant, and I'll say so in the commit message.

I'll also fix the commit message on the old copy path, and give
net_mp_release_page_pool_bulk() its own page_pool patch.


Björn