Re: [PATCH net-next-2.6] net: copy_rtnl_link_stats64() simplification

[Eric Dumazet <eric.dumazet@gmail.com>]

Le lundi 23 août 2010 à 10:47 -0700, Joe Perches a écrit :
> On Mon, 2010-08-23 at 19:14 +0200, Eric Dumazet wrote:
> > No need to use a temporary struct rtnl_link_stats64 variable,
> > just copy the source to skb buffer.
> > 
> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> 
> Maybe it's better to use the same argument style as copy_rtnl_link_stats
> 
>  net/core/rtnetlink.c |   36 ++++--------------------------------
>  1 files changed, 4 insertions(+), 32 deletions(-)
> 
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index f78d821..f8781db 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -610,38 +610,10 @@ static void copy_rtnl_link_stats(struct rtnl_link_stats *a,
>  	a->tx_compressed = b->tx_compressed;
>  }
>  
> -static void copy_rtnl_link_stats64(void *v, const struct rtnl_link_stats64 *b)
> +static void copy_rtnl_link_stats64(struct rtnl_link_stats64 *a,
> +				   const struct rtnl_link_stats64 *b)
>  {



Nope, we have no quarantee of v being aligned on a u64

If you tell compiler first argument is a pointer to rtnl_link_stats64,
it might use 64bit stores and trap.