Subject: Re: [RFC(v2) net-next 08/13] ipv6: Do not deoend on rt->n in ip6_dst_lookup_tail().

From: Cong Wang <[email-masked]>
Date: Wed, 16 Jan 2013 14:49:58 +0800

s/deoend/depend/ in $subject...

On 01/16/2013 12:46 AM, YOSHIFUJI Hideaki wrote:
> Signed-off-by: YOSHIFUJI Hideaki <[email-masked]>
> ---
>   net/ipv6/ip6_output.c |    8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
> index 9fc5d1d..b2fe048 100644
> --- a/net/ipv6/ip6_output.c
> +++ b/net/ipv6/ip6_output.c
> @@ -921,8 +921,12 @@ static int ip6_dst_lookup_tail(struct sock *sk,
>   	 * dst entry of the nexthop router
>   	 */
>   	rt = (struct rt6_info *) *dst;
> -	n = rt->n;
> -	if (n && !(n->nud_state & NUD_VALID)) {
> +	rcu_read_lock_bh();
> +	n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt, &fl6->daddr));
> +	err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
> +	rcu_read_unlock_bh();
> +
> +	if (err) {

Are you sure the logic here equals?

In the original code, we could return 0 even we enter this if branch,
but after your patch, it seems it will return -EINVAL?