Re: [dpdk-dev] [PATCH] bpf: delete meaningless code

["Min Hu (Connor)" <humin29@huawei.com>]

在 2021/4/22 19:29, Ananyev, Konstantin 写道:
> 
>   
>>
>> 在 2021/4/21 19:43, Ananyev, Konstantin 写道:
>>>>
>>>> 'rd->u.max = rd->u.max' is meaningless which should be deleted.
>>>>
>>>> This patch fixed it.
>>>>
>>>> Fixes: 8021917293d0 ("bpf: add extra validation for input BPF program")
>>>> Cc: stable@dpdk.org
>>>
>>> As I remember, I did it on purpose.
>>> Some old (but still supported) version of clang complained
>>> about unitialized variable.
>>
>> Well, how about like this ?
>> 		uint64_t tmp = rd->u.max;
>> 		if (op == BPF_MOD)
>> 			tmp = RTE_MIN(tmp, tmp - 1);
>> 		rd->u.max = tmp;
> 
> 
> Then, I think it should be:
> tmp = RTE_MIN(tmp, rs->u.max - 1);
> 
> Or just leave things as they are right now.
> Nothing is broken here.
> 
OK, this patch can be abandoned ,thanks.
>>>
>>>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>>>> ---
>>>>    lib/librte_bpf/bpf_validate.c | 2 --
>>>>    1 file changed, 2 deletions(-)
>>>>
>>>> diff --git a/lib/librte_bpf/bpf_validate.c b/lib/librte_bpf/bpf_validate.c
>>>> index 9214f15..c5ad951 100644
>>>> --- a/lib/librte_bpf/bpf_validate.c
>>>> +++ b/lib/librte_bpf/bpf_validate.c
>>>> @@ -517,8 +517,6 @@ eval_divmod(uint32_t op, struct bpf_reg_val *rd, struct bpf_reg_val *rs,
>>>>    	} else {
>>>>    		if (op == BPF_MOD)
>>>>    			rd->u.max = RTE_MIN(rd->u.max, rs->u.max - 1);
>>>> -		else
>>>> -			rd->u.max = rd->u.max;
>>>>    		rd->u.min = 0;
>>>>    	}
>>>>
>>>> --
>>>> 2.7.4
>>>
>>> .
>>>
> .
>