netdev - Re: [PATCH net] ipv6: addrconf: Fix recursive spin lock call

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Message-ID: <1454355982.7627.185.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Mon, 01 Feb 2016 11:46:22 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	subashab@...eaurora.org
Cc:	Erik Kline <ek@...gle.com>, Netdev <netdev@...r.kernel.org>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>
Subject: Re: [PATCH net] ipv6: addrconf: Fix recursive spin lock call

On Mon, 2016-02-01 at 11:37 -0800, Eric Dumazet wrote:

> I would rather try :
> 
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 38eeddedfc21..d6b7ab07f914 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -3538,6 +3538,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
>  {
>  	struct inet6_dev *idev = ifp->idev;
>  	struct net_device *dev = idev->dev;
> +	bool notify = false;
>  
>  	addrconf_join_solict(dev, &ifp->addr);
>  
> @@ -3583,7 +3584,8 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
>  			/* Because optimistic nodes can use this address,
>  			 * notify listeners. If DAD fails, RTM_DELADDR is sent.
>  			 */
> -			ipv6_ifa_notify(RTM_NEWADDR, ifp);
> +			notify = true;
> +			in6_ifa_hold(ifp);

Actually the in6_ifa_hold() is not needed.

>  		}
>  	}
>  
> @@ -3591,6 +3593,10 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
>  out:
>  	spin_unlock(&ifp->lock);
>  	read_unlock_bh(&idev->lock);
> +	if (notify) {
> +		ipv6_ifa_notify(RTM_NEWADDR, ifp);
> +		in6_ifa_put(ifp);

And in6_ifa_put() not needed once in6_ifa_hold() is removed.

> +	}
>  }
>  
>  static void addrconf_dad_start(struct inet6_ifaddr *ifp)
> 
> 
>