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From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Quentin Monnet <qmo@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Eduard Zingerman <eddyz87@gmail.com>,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	Jiri Olsa <jolsa@kernel.org>,
	Emil Tsalapatis <emil@etsalapatis.com>,
	Ihor Solodrai <ihor.solodrai@linux.dev>,
	Larysa Zaremba <larysa.zaremba@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Stanislav Fomichev <sdf@fomichev.me>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	bpf@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH bpf-next v3 1/4] bpftool: Set BPF_F_XDP_DEV_BOUND_ONLY flag non-destructively
Date: Thu, 03 Sep 2026 09:53:50 +0200	[thread overview]
Message-ID: <87bjaevkhd.fsf@toke.dk> (raw)
In-Reply-To: <CAEf4BzacBUMLREUObGo5544wyD+mm1=y8ZTnzd7OdDL-c==mMA@mail.gmail.com>

Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:

> On Tue, Sep 1, 2026 at 1:47 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>>
>> When setting the XDP hints ifname, bpftool would set the
>> BPF_F_XDP_DEV_BOUND_ONLY without looking at the existing program flags,
>> overriding any other flag values. This was always a destructive action,
>> but after we change libbpf to carry the frags section flag in
>> prog_flags, this can impact bpftool loading of XDP frags programs.
>>
>> Change the flag setting to be non-destructive by OR'ing it with the
>> existing flags.
>>
>> Fixes: f46392ee3dec ("bpftool: Specify XDP Hints ifname when loading program")
>> Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>> ---
>>  tools/bpf/bpftool/prog.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
>> index a9f730d407a9..8c2f9255b36d 100644
>> --- a/tools/bpf/bpftool/prog.c
>> +++ b/tools/bpf/bpftool/prog.c
>> @@ -1769,7 +1769,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
>>                 }
>>
>>                 if (prog_type == BPF_PROG_TYPE_XDP && xdpmeta_ifindex) {
>> -                       bpf_program__set_flags(pos, BPF_F_XDP_DEV_BOUND_ONLY);
>> +                       bpf_program__set_flags(pos, bpf_program__flags(pos) | BPF_F_XDP_DEV_BOUND_ONLY);
>
> maybe we should just add bpf_program__add_flags() and
> bpf_program__clear_flags() to make life a touch easier and code in
> selftests and bpftool a touch less verbose?

Sure, I can follow up with those. Also makes for a convenient feature
detection target for this change :)

-Toke


  reply	other threads:[~2026-09-03  7:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-01  8:46 [PATCH bpf-next v3 0/4] libbpf: Move section-defined program flags to prog_flags Toke Høiland-Jørgensen
2026-09-01  8:46 ` [PATCH bpf-next v3 1/4] bpftool: Set BPF_F_XDP_DEV_BOUND_ONLY flag non-destructively Toke Høiland-Jørgensen
2026-09-03  0:22   ` Andrii Nakryiko
2026-09-03  7:53     ` Toke Høiland-Jørgensen [this message]
2026-09-01  8:46 ` [PATCH bpf-next v3 2/4] selftests/bpf: Set BPF program flags non-destructively Toke Høiland-Jørgensen
2026-09-01  9:54   ` bot+bpf-ci
2026-09-01  8:46 ` [PATCH bpf-next v3 3/4] libbpf: Move section-defined program flags to prog_flags Toke Høiland-Jørgensen
2026-09-01  9:54   ` bot+bpf-ci
2026-09-03  0:22     ` Andrii Nakryiko
2026-09-01  8:46 ` [PATCH bpf-next v3 4/4] selftests/bpf: Check for flag presence in bpf_program__flags() Toke Høiland-Jørgensen
2026-09-03  0:30 ` [PATCH bpf-next v3 0/4] libbpf: Move section-defined program flags to prog_flags patchwork-bot+netdevbpf

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