linux-kernel - Re: [PATCH 4/4] staging: r8188eu: use htons macro instead of __constant

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Message-ID: <49002a284dd29b8f784b52cb1527e687183ca175.camel@perches.com>
Date:   Tue, 18 Oct 2022 23:08:06 -0700
From:   Joe Perches <joe@...ches.com>
To:     Deepak R Varma <drv@...lo.com>, outreachy@...ts.linux.dev,
        Larry.Finger@...inger.net, phil@...lpotter.co.uk,
        paskripkin@...il.com, gregkh@...uxfoundation.org,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Cc:     kumarpraveen@...ux.microsoft.com, saurabh.truth@...il.com
Subject: Re: [PATCH 4/4] staging: r8188eu: use htons macro instead of
 __constant_htons

On Mon, 2022-10-17 at 18:54 +0530, Deepak R Varma wrote:
> Macro "htons" is more efficiant and clearer. It should be used for
> constants instead of the __contast_htons macro. Resolves following

typo: __constant_htons

> checkpatch script complaint:
> 	WARNING: __constant_htons should be htons
[]
> diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c b/drivers/staging/r8188eu/core/rtw_br_ext.c
[]
> @@ -612,14 +612,14 @@ void dhcp_flag_bcast(struct adapter *priv, struct sk_buff *skb)
>  	if (!priv->ethBrExtInfo.dhcp_bcst_disable) {
>  		__be16 protocol = *((__be16 *)(skb->data + 2 * ETH_ALEN));
> 
> -		if (protocol == __constant_htons(ETH_P_IP)) { /*  IP */
> +		if (protocol == htons(ETH_P_IP)) { /*  IP */
>  			struct iphdr *iph = (struct iphdr *)(skb->data + ETH_HLEN);
> 
>  			if (iph->protocol == IPPROTO_UDP) { /*  UDP */
>  				struct udphdr *udph = (struct udphdr *)((size_t)iph + (iph->ihl << 2));
> 
> -				if ((udph->source == __constant_htons(CLIENT_PORT)) &&
> -				    (udph->dest == __constant_htons(SERVER_PORT))) { /*  DHCP request */
> +				if ((udph->source == htons(CLIENT_PORT)) &&
> +				    (udph->dest == htons(SERVER_PORT))) { /*  DHCP request */

OK, this bit seems fine

>  					struct dhcpMessage *dhcph =
>  						(struct dhcpMessage *)((size_t)udph + sizeof(struct udphdr));

IMO: this existing code however is ugly.
     Casting a pointer to a size_t isn't great.

Perhaps:

				struct dhcpMessage *dhcp;

				dhcp = (void *)udhp + sizeof(struct udphdr);

in a separate patch.

> 					u32 cookie = be32_to_cpu((__be32)dhcph->cookie);

And dhcph->cookie already is a __be32 so the cast is pointless.

drivers/staging/r8188eu/core/rtw_br_ext.c-598-  __be32 cookie;