netdev - Re: [net-next] arp: correct return value of arp

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Date:	Thu, 03 Mar 2016 16:30:01 -0500 (EST)
From:	David Miller <davem@...emloft.net>
To:	zhangshengju@...s.chinamobile.com
Cc:	netdev@...r.kernel.org
Subject: Re: [net-next] arp: correct return value of arp_rcv

From: Zhang Shengju <zhangshengju@...s.chinamobile.com>
Date: Tue,  1 Mar 2016 07:24:42 +0000

> Currently, arp_rcv() always return zero on a packet delivery upcall.
> 
> To make its behavior more compliant with the way this API should be
> used, this patch changes this to let it return NET_RX_SUCCESS when the
> packet is proper handled, and NET_RX_DROP otherwise.
> 
> Signed-off-by: Zhang Shengju <zhangshengju@...s.chinamobile.com>

This change is bogus.

> @@ -880,7 +880,7 @@ out:
>  	consume_skb(skb);
>  out_free_dst:
>  	dst_release(reply_dst);
> -	return 0;
> +	return NET_RX_SUCCESS;

Most of the paths to out: are dropping the request for one reason or
another.

If you want to do this right you need to split these two exit paths,
convert consume_skb() to kfree_skb() in the drop path, and then you
can return accurate NET_* codes.