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SubjectRe: [PATCH 1/2] bpf: Remove struct bpf_verifier_env argument from print_bpf_insn
On Wed, Mar 21, 2018 at 05:25:33PM +0000, Quentin Monnet wrote:
> 2018-03-21 16:02 UTC+0100 ~ Jiri Olsa <jolsa@kernel.org>
> > We use print_bpf_insn in user space (bpftool and soon perf),
> > so it'd be nice to keep it generic and strip it off the kernel
> > struct bpf_verifier_env argument.
> >
> > This argument can be safely removed, because its users can
> > use the struct bpf_insn_cbs::private_data to pass it.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > kernel/bpf/disasm.c | 52 +++++++++++++++++++++++++--------------------------
> > kernel/bpf/disasm.h | 5 +----
> > kernel/bpf/verifier.c | 6 +++---
> > 3 files changed, 30 insertions(+), 33 deletions(-)
> >
>
> [...]
>
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index c6eff108aa99..9f27d3fa7259 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -202,8 +202,7 @@ EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
> > * generic for symbol export. The function was renamed, but not the calls in
> > * the verifier to avoid complicating backports. Hence the alias below.
> > */
> > -static __printf(2, 3) void verbose(struct bpf_verifier_env *env,
> > - const char *fmt, ...)
> > +static __printf(2, 3) void verbose(void *private_data, const char *fmt, ...)
> > __attribute__((alias("bpf_verifier_log_write")));
>
> Just as a note, verbose() will be aliased to a function whose prototype
> differs (bpf_verifier_log_write() still expects a struct
> bpf_verifier_env as its first argument). I am not so familiar with
> function aliases, could this change be a concern?

yea, but as it was pointer for pointer switch I did not
see any problem with that.. I'll check more

jirka

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