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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Mon, 31 Jul 2023 19:24:25 -0700
Message-ID: <CAADnVQJz41QgpFHr3k0pndjHZ8ragH--=C_bYxrzitj7bN3bbg@mail.gmail.com>
Subject: Re: [PATCH v4 3/9] bpf/btf: Add a function to search a member of a struct/union
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
        linux-trace-kernel@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        bpf <bpf@vger.kernel.org>, Sven Schnelle <svens@linux.ibm.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
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On Mon, Jul 31, 2023 at 6:15=E2=80=AFPM Steven Rostedt <rostedt@goodmis.org=
> wrote:
>
> On Mon, 31 Jul 2023 14:59:47 -0700
> Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> > Assuming that is addressed. How do we merge the series?
> > The first 3 patches have serious conflicts with bpf trees.
> >
> > Maybe send the first 3 with extra selftest for above recursion
> > targeting bpf-next then we can have a merge commit that Steven can pull
> > into tracing?
>
> Would it be possible to do this by basing it off of one of Linus's tags,
> and doing the merge and conflict resolution in your tree before it gets t=
o
> Linus?
>
> That way we can pull in that clean branch without having to pull in
> anything else from BPF. I believe Linus prefers this over having tracing
> having extra changes from BPF that are not yet in his tree. We only need
> these particular changes, we shouldn't be pulling in anything specific fo=
r
> BPF, as I believe that will cause issues on Linus's side.

We can try, but I suspect git tricks won't do it.
Masami's changes depend on patches for kernel/bpf/btf.c that
are already in bpf-next, so git would have to follow all commits
that touch this file. I don't think git is smart enough to
thread the needle and split the commit into files. If one commit touches
btf.c and something else that whole commit becomes a dependency
that pulls another commit with all files touched by
the previous commit and so on.
tbh for this set, the easiest for everyone, is to land the whole thing
through bpf-next, since there are no conflicts on fprobe side.