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From: Hangbin Liu <haliu@redhat.com>
To: Martynas Pumputis <m@lambda.lt>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Networking <netdev@vger.kernel.org>,
	Stephen Hemminger <stephen@networkplumber.org>,
	David Ahern <dsahern@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [PATCH iproute2] libbpf: fix attach of prog with multiple sections
Date: Fri, 23 Jul 2021 12:41:30 +0800	[thread overview]
Message-ID: <YPpIeppWpqFCSaqZ@Laptop-X1> (raw)
In-Reply-To: <df3396c3-9a4a-824d-648f-69f4da5bc78b@lambda.lt>

On Wed, Jul 21, 2021 at 04:47:14PM +0200, Martynas Pumputis wrote:
> > > diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c
> > > index d05737a4..f76b90d2 100644
> > > --- a/lib/bpf_libbpf.c
> > > +++ b/lib/bpf_libbpf.c
> > > @@ -267,10 +267,12 @@ static int load_bpf_object(struct bpf_cfg_in *cfg)
> > >          }
> > > 
> > >          bpf_object__for_each_program(p, obj) {
> > > +               bool prog_to_attach = !prog && cfg->section &&
> > > +                       !strcmp(get_bpf_program__section_name(p), cfg->section);
> > 
> > This is still problematic, because one section can have multiple BPF
> > programs. I.e., it's possible two define two or more XDP BPF programs
> > all with SEC("xdp") and libbpf works just fine with that. I suggest
> > moving users to specify the program name (i.e., C function name
> > representing the BPF program). All the xdp_mycustom_suffix namings are
> > a hack and will be rejected by libbpf 1.0, so it would be great to get
> > a head start on fixing this early on.
> 
> Thanks for bringing this up. Currently, there is no way to specify a
> function name with "tc exec bpf" (only a section name via the "sec" arg). So
> probably, we should just add another arg to specify the function name.

How about add a "prog" arg to load specified program name and mark
"sec" as not recommended? To keep backwards compatibility we just load the
first program in the section.

Thanks
Hangbin


  parent reply	other threads:[~2021-07-23  4:41 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05 12:43 Martynas Pumputis
2021-07-06  2:44 ` Hangbin Liu
2021-07-20 20:27 ` Andrii Nakryiko
2021-07-21 14:47   ` Martynas Pumputis
2021-07-21 14:59     ` David Ahern
2021-07-21 15:27       ` Martynas Pumputis
2021-07-23  4:01         ` Andrii Nakryiko
2021-07-23  4:41     ` Hangbin Liu [this message]
2021-07-23  4:51       ` Andrii Nakryiko
2021-07-23  7:55         ` Hangbin Liu
2021-07-23 16:09           ` Andrii Nakryiko
2021-07-24  8:12             ` Hangbin Liu
2021-07-24  0:12         ` David Ahern
2021-07-24  0:25           ` Andrii Nakryiko
2021-07-26 13:58             ` David Ahern
2021-07-26 15:13               ` Andrii Nakryiko
2021-07-27  2:51                 ` David Ahern
2021-07-27 19:05                   ` Andrii Nakryiko

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