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

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Message-ID: <aaa5deae-1a79-b02f-75ee-37a31383e40c@huawei.com>
Date:   Tue, 15 Nov 2022 22:12:33 +0800
From:   Hao Lan <lanhao@...wei.com>
To:     Leon Romanovsky <leon@...nel.org>,
        Guangbin Huang <huangguangbin2@...wei.com>
CC:     <davem@...emloft.net>, <kuba@...nel.org>, <edumazet@...gle.com>,
        <pabeni@...hat.com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <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.
Thanks.

On 2022/9/28 18:28, 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?
we use '&', just define a bitwise AND, not define 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
>>
> .
>