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Message-ID: <1453992162.7627.35.camel@edumazet-glaptop2.roam.corp.google.com>
Subject: Re: [PATCH net 0/4] net: add rx_unhandled stat counter
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jarod Wilson <jarod@redhat.com>
Cc: linux-kernel@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>, Jiri Pirko <jiri@mellanox.com>,
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        Veaceslav Falico <vfalico@gmail.com>,
        Andy Gospodarek <gospo@cumulusnetworks.com>, netdev@vger.kernel.org
Date: Thu, 28 Jan 2016 06:42:42 -0800
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On Thu, 2016-01-28 at 09:38 -0500, Jarod Wilson wrote:

> Something like this then:
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 82334c6..2ca3eab 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -7262,15 +7262,16 @@ void netdev_run_todo(void)
>  void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
>  			     const struct net_device_stats *netdev_stats)
>  {
> +	memset(stats64, 0, sizeof(*stats64));
>  #if BITS_PER_LONG == 64
> -	BUILD_BUG_ON(sizeof(*stats64) != sizeof(*netdev_stats));
> +	BUILD_BUG_ON(sizeof(*stats64) < sizeof(*netdev_stats));
>  	memcpy(stats64, netdev_stats, sizeof(*stats64));
>  #else
>  	size_t i, n = sizeof(*stats64) / sizeof(u64);
>  	const unsigned long *src = (const unsigned long *)netdev_stats;
>  	u64 *dst = (u64 *)stats64;
>  
> -	BUILD_BUG_ON(sizeof(*netdev_stats) / sizeof(unsigned long) !=
> +	BUILD_BUG_ON(sizeof(*netdev_stats) / sizeof(unsigned long) >
>  		     sizeof(*stats64) / sizeof(u64));
>  	for (i = 0; i < n; i++)
>  		dst[i] = src[i];
> 
> Compiles locally w/o that net_device_stats addition, seems sane to me.
> 

Sure, you also can set stats64->rx_unhandled to 0 here, just to be 100%
safe.

Thanks.