[PATCH] net/txgbe: fix a bit with boolean operator

[Ferruh Yigit]

On 3/3/2022 1:31 PM, Weiguo Li wrote:
> On March 2, 2022, 5:23 p.m Ferruh Yigit wrote:
>> On 3/2/2022 8:02 AM, Jiawen Wu wrote:
>>> On March 1, 2022 2:09 PM, Weiguo Li wrote:
>>>> Since boolean value is in 0 and 1, it's strange to combines a boolean
>>> value with
>>>> a bit operator.
>>>>
>>>> Thus it's highly possible a typo error with "if (A & !B)", and more
>>> probably to
>>>> use "if (A & ~B)" instead.
>>>>
>>>> Fixes: c1d4e9d37abdc6 ("net/txgbe: add queue stats mapping")
>>>>
>>>> Signed-off-by: Weiguo Li <liwg06 at foxmail.com>
>>>> ---
>>>>    drivers/net/txgbe/txgbe_ethdev.c | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/net/txgbe/txgbe_ethdev.c
>>>> b/drivers/net/txgbe/txgbe_ethdev.c
>>>> index 19d4444748..f0994f028d 100644
>>>> --- a/drivers/net/txgbe/txgbe_ethdev.c
>>>> +++ b/drivers/net/txgbe/txgbe_ethdev.c
>>>> @@ -376,7 +376,7 @@ txgbe_dev_queue_stats_mapping_set(struct
>>>> rte_eth_dev *eth_dev,
>>>>    	if (hw->mac.type != txgbe_mac_raptor)
>>>>    		return -ENOSYS;
>>>>
>>>> -	if (stat_idx & !QMAP_FIELD_RESERVED_BITS_MASK)
>>>> +	if (stat_idx & ~QMAP_FIELD_RESERVED_BITS_MASK)
>>>>    		return -EIO;
>>>>
>>>>    	PMD_INIT_LOG(DEBUG, "Setting port %d, %s queue_id %d to stat
>>>> index %d",
>>>> --
>>>> 2.25.1
>>>
>>> Thanks.
>>>
>>> Acked-by: Jiawen Wu <jiawenwu at trustnetic.com>
>>>
>>
>> Hi Weiguo,
>>
>> Good catch, I wonder how did you detect this?
>>
>> If there is an automated way, maybe we can consider using
>> it in our CI.
>>
> 
> Hi Ferruh,
> 
> It's found by a coccinell script:
> 
> @fix_bit_boolean @ expression E; constant C; @@
> (
>    !E & !C
> |
> - !E & C
> + !(E & C)
> |
> - E & !C
> + E & ~C
> )
> 
> the idea came from a demo script in coccinelle website:
> (https://coccinelle.gitlabpages.inria.fr/website/rules/notand.html)
> 
> @@ expression E; constant C; @@
> (
>    !E & !C
> |
> - !E & C
> + !(E & C)
> )
> 
> The difference is in the last two lines and by which found the problem.
> 
> I'd be happy if it would used in CI.
> Maybe better to let Julia know, since she's the original author.
> cc Julia
> 

Thanks Weiguo. cc'ed lab people and Ali too.

Aaron, lab, what do you think, can this be added into CI checks?