Re: [PATCH bpf-next 4/5] bpftool: Add SEC name for xdp programs attached to device map

On Wed, 27 May 2020 17:01:10 +0200
Toke Høiland-Jørgensen [off-list ref] wrote:

David Ahern [off-list ref] writes:

quoted

On 5/27/20 4:02 AM, Toke Høiland-Jørgensen wrote:  

quoted

David Ahern [off-list ref] writes:
  

quoted

Support SEC("xdp_dm*") as a short cut for loading the program with
type BPF_PROG_TYPE_XDP and expected attach type BPF_XDP_DEVMAP.  

You're not using this in the selftest; shouldn't you be? Also, the
prefix should be libbpf: not bpftool:, no?
  

The selftest is exercising kernel APIs - what is allowed and what is
not.  

Sure, but they also de facto serve as example code for features that are
not documented anywhere else, so just seemed a bit odd to me that you
were not using this to mark the programs.

Anyway, not going to insist if you prefer explicitly setting
expected_attach_type...

I actually think that it is better to demonstrate that it is possible to set:	

 attr.expected_attach_type = BPF_XDP_DEVMAP;

Because people will be grepping the source code to find examples ;-)

We could add a comment, that say SEC("xdp_dm") can be used as short cut.
-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer