linux-kernel - Re: [PATCH net-next 1/4] net: hns3: refine the tcam key convert handle

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Date:   Tue, 15 Nov 2022 14:00:37 +0000
From:   "Lanhao (Lan)" <lanhao@...wei.com>
To:     Leon Romanovsky <leon@...nel.org>,
        "huangguangbin (A)" <huangguangbin2@...wei.com>
CC:     "davem@...emloft.net" <davem@...emloft.net>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "pabeni@...hat.com" <pabeni@...hat.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "shenjian (K)" <shenjian15@...wei.com>
Subject: Re: [PATCH net-next 1/4] net: hns3: refine the tcam key convert
 handle

Can you please explain why do you need special define for boolean AND?
we use '&', just define a bitwise AND, not define boolean AND.

On Tue, Sep 28, 2022 at 10:28:02AM +0800, Leon Romanovsky wrote:
>On Tue, Sep 27, 2022 at 07:12:02PM +0800, Guangbin Huang wrote:
>> From: Jian Shen <shenjian15@...wei.com>
>> 
>> The expression '(k ^ ~v)' is exaclty '(k & v)', and '(k & v) & k' is 
>> exaclty 'k & v'. So simplify the expression for tcam key convert.
>> 
>> It also add necessary brackets for them.
>> 
>> Signed-off-by: Jian Shen <shenjian15@...wei.com>
>> Signed-off-by: Guangbin Huang <huangguangbin2@...wei.com>
>> ---
>>  .../net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h   | 11 +++--------
>>  1 file changed, 3 insertions(+), 8 deletions(-)
>> 
>> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h 
>> b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
>> index 495b639b0dc2..59bfacc687c9 100644
>> --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
>> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
>> @@ -827,15 +827,10 @@ struct hclge_vf_vlan_cfg {
>>   * Then for input key(k) and mask(v), we can calculate the value by
>>   * the formulae:
>>   *	x = (~k) & v
>> - *	y = (k ^ ~v) & k
>> + *	y = k & v
>>   */
>> -#define calc_x(x, k, v) (x = ~(k) & (v)) -#define calc_y(y, k, v) \
>> -	do { \
>> -		const typeof(k) _k_ = (k); \
>> -		const typeof(v) _v_ = (v); \
>> -		(y) = (_k_ ^ ~_v_) & (_k_); \
>> -	} while (0)
>> +#define calc_x(x, k, v) ((x) = ~(k) & (v)) #define calc_y(y, k, v) 
>> +((y) = (k) & (v))
>
>Can you please explain why do you need special define for boolean AND?
>
>Thanks
we use '&', just define a bitwise AND, not define boolean AND.
>
>>  
>>  #define HCLGE_MAC_STATS_FIELD_OFF(f) (offsetof(struct 
>> hclge_mac_stats, f))  #define HCLGE_STATS_READ(p, offset) (*(u64 
>> *)((u8 *)(p) + (offset)))
>> --
>> 2.33.0
>> 
>

-----邮件原件-----
发件人: Leon Romanovsky <leon@...nel.org> 
发送时间: 2022年9月28日 18:29
收件人: huangguangbin (A) <huangguangbin2@...wei.com>
抄送: davem@...emloft.net; kuba@...nel.org; edumazet@...gle.com; pabeni@...hat.com; netdev@...r.kernel.org; linux-kernel@...r.kernel.org; shenjian (K) <shenjian15@...wei.com>; Lanhao (Lan) <lanhao@...wei.com>
主题: Re: [PATCH net-next 1/4] net: hns3: refine the tcam key convert handle

On Tue, Sep 27, 2022 at 07:12:02PM +0800, Guangbin Huang wrote:
> From: Jian Shen <shenjian15@...wei.com>
> 
> The expression '(k ^ ~v)' is exaclty '(k & v)', and '(k & v) & k' is 
> exaclty 'k & v'. So simplify the expression for tcam key convert.
> 
> It also add necessary brackets for them.
> 
> Signed-off-by: Jian Shen <shenjian15@...wei.com>
> Signed-off-by: Guangbin Huang <huangguangbin2@...wei.com>
> ---
>  .../net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h   | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h 
> b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
> index 495b639b0dc2..59bfacc687c9 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
> @@ -827,15 +827,10 @@ struct hclge_vf_vlan_cfg {
>   * Then for input key(k) and mask(v), we can calculate the value by
>   * the formulae:
>   *	x = (~k) & v
> - *	y = (k ^ ~v) & k
> + *	y = k & v
>   */
> -#define calc_x(x, k, v) (x = ~(k) & (v)) -#define calc_y(y, k, v) \
> -	do { \
> -		const typeof(k) _k_ = (k); \
> -		const typeof(v) _v_ = (v); \
> -		(y) = (_k_ ^ ~_v_) & (_k_); \
> -	} while (0)
> +#define calc_x(x, k, v) ((x) = ~(k) & (v)) #define calc_y(y, k, v) 
> +((y) = (k) & (v))

Can you please explain why do you need special define for boolean AND?

Thanks

>  
>  #define HCLGE_MAC_STATS_FIELD_OFF(f) (offsetof(struct 
> hclge_mac_stats, f))  #define HCLGE_STATS_READ(p, offset) (*(u64 
> *)((u8 *)(p) + (offset)))
> --
> 2.33.0
>