* [PATCH -next] bpf: remove set but not used variable 'dst_known'
@ 2020-04-13 11:37 Mao Wenan
2020-04-14 22:05 ` Song Liu
0 siblings, 1 reply; 8+ messages in thread
From: Mao Wenan @ 2020-04-13 11:37 UTC (permalink / raw)
To: ast, daniel, kafai, songliubraving, yhs, andriin, john.fastabend,
kpsingh
Cc: netdev, bpf, linux-kernel, kernel-janitors
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]
It is not used since commit f1174f77b50c ("bpf/verifier:
rework value tracking")
Signed-off-by: Mao Wenan <maowenan@huawei.com>
---
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;
s64 smin_val, smax_val;
u64 umin_val, umax_val;
s32 s32_min_val, s32_max_val;
@@ -5622,7 +5622,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
if (alu32) {
src_known = tnum_subreg_is_const(src_reg.var_off);
- dst_known = tnum_subreg_is_const(dst_reg->var_off);
if ((src_known &&
(s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
@@ -5634,7 +5633,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
}
} else {
src_known = tnum_is_const(src_reg.var_off);
- dst_known = tnum_is_const(dst_reg->var_off);
if ((src_known &&
(smin_val != smax_val || umin_val != umax_val)) ||
smin_val > smax_val || umin_val > umax_val) {
--
2.17.1
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH -next] bpf: remove set but not used variable 'dst_known'
2020-04-13 11:37 [PATCH -next] bpf: remove set but not used variable 'dst_known' Mao Wenan
@ 2020-04-14 22:05 ` Song Liu
2020-04-15 1:37 ` maowenan
0 siblings, 1 reply; 8+ messages in thread
From: Song Liu @ 2020-04-14 22:05 UTC (permalink / raw)
To: Mao Wenan
Cc: Alexei Starovoitov, Daniel Borkmann, Martin Lau, Yonghong Song,
Andrii Nakryiko, john.fastabend, kpsingh, netdev, bpf,
linux-kernel, kernel-janitors
> On Apr 13, 2020, at 4:37 AM, Mao Wenan <maowenan@huawei.com> 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]
>
> It is not used since commit f1174f77b50c ("bpf/verifier:
> rework value tracking")
The fix makes sense. But I think f1174f77b50c introduced dst_known,
so this statement is not accurate.
>
> Signed-off-by: Mao Wenan <maowenan@huawei.com>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH -next] bpf: remove set but not used variable 'dst_known'
2020-04-14 22:05 ` Song Liu
@ 2020-04-15 1:37 ` maowenan
2020-04-15 7:23 ` Song Liu
0 siblings, 1 reply; 8+ messages in thread
From: maowenan @ 2020-04-15 1:37 UTC (permalink / raw)
To: Song Liu
Cc: Alexei Starovoitov, Daniel Borkmann, Martin Lau, Yonghong Song,
Andrii Nakryiko, john.fastabend, kpsingh, netdev, bpf,
linux-kernel, kernel-janitors
On 2020/4/15 6:05, Song Liu wrote:
>
>
>> On Apr 13, 2020, at 4:37 AM, Mao Wenan <maowenan@huawei.com> 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]
>>
>> It is not used since commit f1174f77b50c ("bpf/verifier:
>> rework value tracking")
>
> The fix makes sense. But I think f1174f77b50c introduced dst_known,
> so this statement is not accurate.
>
thanks for review, yes, f1174f77b50c introduced dst_known, and below commit
doesn't deference variable dst_known. So I send v2 later?
3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")
>>
>> Signed-off-by: Mao Wenan <maowenan@huawei.com>
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH -next] bpf: remove set but not used variable 'dst_known'
2020-04-15 1:37 ` maowenan
@ 2020-04-15 7:23 ` Song Liu
2020-04-15 7:52 ` maowenan
0 siblings, 1 reply; 8+ messages in thread
From: Song Liu @ 2020-04-15 7:23 UTC (permalink / raw)
To: maowenan
Cc: Alexei Starovoitov, Daniel Borkmann, Martin Lau, Yonghong Song,
Andrii Nakryiko, john.fastabend, kpsingh, netdev, bpf,
linux-kernel, kernel-janitors
> On Apr 14, 2020, at 6:37 PM, maowenan <maowenan@huawei.com> wrote:
>
> On 2020/4/15 6:05, Song Liu wrote:
>>
>>
>>> On Apr 13, 2020, at 4:37 AM, Mao Wenan <maowenan@huawei.com> 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]
>>>
>>> It is not used since commit f1174f77b50c ("bpf/verifier:
>>> rework value tracking")
>>
>> The fix makes sense. But I think f1174f77b50c introduced dst_known,
>> so this statement is not accurate.
>>
> thanks for review, yes, f1174f77b50c introduced dst_known, and below commit
> doesn't deference variable dst_known. So I send v2 later?
> 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")
I don't think we need to back port this to stable. So it is OK not to
include Fixes tag. We can just remove this statement in the commit log.
bpf-next is not open yet. Please send v2 when bpf-next is open.
Thanks,
Song
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH -next] bpf: remove set but not used variable 'dst_known'
2020-04-15 7:23 ` Song Liu
@ 2020-04-15 7:52 ` maowenan
2020-04-18 1:37 ` [PATCH bpf-next v2] " Mao Wenan
0 siblings, 1 reply; 8+ messages in thread
From: maowenan @ 2020-04-15 7:52 UTC (permalink / raw)
To: Song Liu
Cc: Alexei Starovoitov, Daniel Borkmann, Martin Lau, Yonghong Song,
Andrii Nakryiko, john.fastabend, kpsingh, netdev, bpf,
linux-kernel, kernel-janitors
On 2020/4/15 15:23, Song Liu wrote:
>
>
>> On Apr 14, 2020, at 6:37 PM, maowenan <maowenan@huawei.com> wrote:
>>
>> On 2020/4/15 6:05, Song Liu wrote:
>>>
>>>
>>>> On Apr 13, 2020, at 4:37 AM, Mao Wenan <maowenan@huawei.com> 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]
>>>>
>>>> It is not used since commit f1174f77b50c ("bpf/verifier:
>>>> rework value tracking")
>>>
>>> The fix makes sense. But I think f1174f77b50c introduced dst_known,
>>> so this statement is not accurate.
>>>
>> thanks for review, yes, f1174f77b50c introduced dst_known, and below commit
>> doesn't deference variable dst_known. So I send v2 later?
>> 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")
>
> I don't think we need to back port this to stable. So it is OK not to
> include Fixes tag. We can just remove this statement in the commit log.
>
> bpf-next is not open yet. Please send v2 when bpf-next is open.
>
> Thanks,
> Song
>
OK, I will do that.
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH bpf-next v2] bpf: remove set but not used variable 'dst_known'
2020-04-15 7:52 ` maowenan
@ 2020-04-18 1:37 ` Mao Wenan
2020-04-18 6:13 ` Song Liu
0 siblings, 1 reply; 8+ messages in thread
From: Mao Wenan @ 2020-04-18 1:37 UTC (permalink / raw)
To: ast, daniel, kafai, songliubraving, yhs, andriin, john.fastabend,
kpsingh
Cc: netdev, bpf, linux-kernel, kernel-janitors
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@huawei.com>
---
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;
s64 smin_val, smax_val;
u64 umin_val, umax_val;
s32 s32_min_val, s32_max_val;
@@ -5622,7 +5622,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
if (alu32) {
src_known = tnum_subreg_is_const(src_reg.var_off);
- dst_known = tnum_subreg_is_const(dst_reg->var_off);
if ((src_known &&
(s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
@@ -5634,7 +5633,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
}
} else {
src_known = tnum_is_const(src_reg.var_off);
- dst_known = tnum_is_const(dst_reg->var_off);
if ((src_known &&
(smin_val != smax_val || umin_val != umax_val)) ||
smin_val > smax_val || umin_val > umax_val) {
--
2.17.1
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH bpf-next v2] bpf: remove set but not used variable 'dst_known'
2020-04-18 1:37 ` [PATCH bpf-next v2] " Mao Wenan
@ 2020-04-18 6:13 ` Song Liu
2020-04-21 3:23 ` Alexei Starovoitov
0 siblings, 1 reply; 8+ messages in thread
From: Song Liu @ 2020-04-18 6:13 UTC (permalink / raw)
To: Mao Wenan
Cc: ast, daniel, Martin Lau, Yonghong Song, Andrii Nakryiko,
john.fastabend, kpsingh, netdev, bpf, linux-kernel,
kernel-janitors
> On Apr 17, 2020, at 6:37 PM, Mao Wenan <maowenan@huawei.com> 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@huawei.com>
Acked-by: Song Liu <songliubraving@fb.com>
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;
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH bpf-next v2] bpf: remove set but not used variable 'dst_known'
2020-04-18 6:13 ` Song Liu
@ 2020-04-21 3:23 ` Alexei Starovoitov
0 siblings, 0 replies; 8+ messages in thread
From: Alexei Starovoitov @ 2020-04-21 3:23 UTC (permalink / raw)
To: Song Liu
Cc: Mao Wenan, ast, daniel, Martin Lau, Yonghong Song,
Andrii Nakryiko, john.fastabend, kpsingh, netdev, bpf,
linux-kernel, kernel-janitors, kernel-team
On Sat, Apr 18, 2020 at 06:13:48AM +0000, Song Liu wrote:
>
>
> > On Apr 17, 2020, at 6:37 PM, Mao Wenan <maowenan@huawei.com> 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@huawei.com>
>
> Acked-by: Song Liu <songliubraving@fb.com>
>
> 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
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-04-21 3:23 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-13 11:37 [PATCH -next] bpf: remove set but not used variable 'dst_known' Mao Wenan
2020-04-14 22:05 ` Song Liu
2020-04-15 1:37 ` maowenan
2020-04-15 7:23 ` Song Liu
2020-04-15 7:52 ` maowenan
2020-04-18 1:37 ` [PATCH bpf-next v2] " Mao Wenan
2020-04-18 6:13 ` Song Liu
2020-04-21 3:23 ` Alexei Starovoitov
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