Re: [PATCH v5 bpf-next 03/14] xdp: add xdp_shared_info data structure

On 2020-12-21 4:01 a.m., Jesper Dangaard Brouer wrote:

On Sat, 19 Dec 2020 10:30:57 -0500

quoted

Sorry to interject:
Does it make sense to use it to store arbitrary metadata or a scratchpad
in this space? Something equivalent to skb->cb which is lacking in
XDP.

Well, XDP have the data_meta area.  But difficult to rely on because a
lot of driver don't implement it.  And Saeed and I plan to use this
area and populate it with driver info from RX-descriptor.

What i was thinking is some scratch pad that i can write to within
an XDP prog (not driver); example, in a prog array map the scratch
pad is written by one program in the array and read by another later on.
skb->cb allows for that. Unless you mean i can already write to some
XDP data_meta area?

cheers,
jamal