On Sat, Apr 18, 2020 at 06:13:48AM +0000, Song Liu wrote:
>
>
> > On Apr 17, 2020, at 6:37 PM, Mao Wenan <maowenan@xxxxxxxxxx> wrote:
> >
> > Fixes gcc '-Wunused-but-set-variable' warning:
> >
> > kernel/bpf/verifier.c:5603:18: warning: variable ‘dst_known’
> > set but not used [-Wunused-but-set-variable], delete this
> > variable.
> >
> > Signed-off-by: Mao Wenan <maowenan@xxxxxxxxxx>
>
> Acked-by: Song Liu <songliubraving@xxxxxx>
>
> With one nit below.
>
> > ---
> > v2: remove fixes tag in commit log.
> > kernel/bpf/verifier.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index 04c6630cc18f..c9f50969a689 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -5600,7 +5600,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
> > {
> > struct bpf_reg_state *regs = cur_regs(env);
> > u8 opcode = BPF_OP(insn->code);
> > - bool src_known, dst_known;
> > + bool src_known;
>
> This is not a hard rule, but we prefer to keep variable definition in
> "reverse Christmas tree" order. Since we are on this function, let's
> reorder these definitions to something like:
>
> u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
> struct bpf_reg_state *regs = cur_regs(env);
> u8 opcode = BPF_OP(insn->code);
> u32 dst = insn->dst_reg;
> s64 smin_val, smax_val;
> u64 umin_val, umax_val;
> bool src_known;
> int ret;
I don't want folks to keep re-sorting variables and making patches difficult
to backport, do git blame, causing bpf vs bpf-next conflicts, etc.
reverse xmas tree is not mandatory. It's a style preference.
I personally do it for new code, but very rarely for fixes.
And certainly not for this kind of cleanup.
Applied. Thanks
