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

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Message-ID: <YzQh4Zu3Md1+Npeo@unreal>
Date:   Wed, 28 Sep 2022 13:28:49 +0300
From:   Leon Romanovsky <leon@...nel.org>
To:     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,
        lanhao@...wei.com
Subject: 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
>