Re: [PATCH RESEND net-next] ipv6: mcast: Add ip6_mc_find_idev() helper

[Paolo Abeni]

On 8/18/25 12:10 PM, Yue Haibing wrote:
> @@ -302,32 +310,18 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
>  }
>  EXPORT_SYMBOL(ipv6_sock_mc_drop);
>  
> -static struct inet6_dev *ip6_mc_find_dev(struct net *net,
> -					 const struct in6_addr *group,
> -					 int ifindex)
> +static struct inet6_dev *ip6_mc_find_idev(struct net *net,
> +					  const struct in6_addr *group,
> +					  int ifindex)
>  {
> -	struct net_device *dev = NULL;
> -	struct inet6_dev *idev;
> -
> -	if (ifindex == 0) {
> -		struct rt6_info *rt;
> +	struct inet6_dev *idev = NULL;
> +	struct net_device *dev;
>  
> -		rcu_read_lock();
> -		rt = rt6_lookup(net, group, NULL, 0, NULL, 0);
> -		if (rt) {
> -			dev = dst_dev(&rt->dst);
> -			dev_hold(dev);
> -			ip6_rt_put(rt);
> -		}
> -		rcu_read_unlock();
> -	} else {
> -		dev = dev_get_by_index(net, ifindex);
> +	dev = ip6_mc_find_dev(net, group, ifindex);
> +	if (dev) {
> +		idev = in6_dev_get(dev);
> +		dev_put(dev);
>  	}
> -	if (!dev)
> -		return NULL;
> -
> -	idev = in6_dev_get(dev);
> -	dev_put(dev);

Not so minor nit: if you omit the last chunk (from 'if (dev) {' onwards,
unneeded), the patch will be much more obvious and smaller. Also you
could clarify a bit the commit message.

You can retain Dawid's ack when posting the next version

/P