Subject: Re: [PATCH net-next 03/12] ipvs: prefer NETDEV_DOWN event to free cached dsts

From: Hans Schillstrom <[email-masked]>
Date: Wed, 06 Mar 2013 10:56:29 +0100

Hi Julian

On Wed, 2013-03-06 at 10:42 +0200, Julian Anastasov wrote:
> 	The real server becomes unreachable on down event,
> no need to wait device unregistration. Should help in
> releasing dsts early before dst->dev is replaced with lo.

Have you test this in a network namespace ?
i.e. kill the namespace with heave traffic through it

From what I remember this was a tricky area...

I have some test cases for this, should I run them ?

> Signed-off-by: Julian Anastasov <[email-masked]>
> ---
>  net/netfilter/ipvs/ip_vs_ctl.c |    8 +++-----
>  1 files changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index c68198b..76fc8f2 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -1512,10 +1512,8 @@ __ip_vs_dev_reset(struct ip_vs_dest *dest, struct net_device *dev)
>  	spin_unlock_bh(&dest->dst_lock);
>  
>  }
> -/*
> - * Netdev event receiver
> - * Currently only NETDEV_UNREGISTER is handled, i.e. if we hold a reference to
> - * a device that is "unregister" it must be released.
> +/* Netdev event receiver
> + * Currently only NETDEV_DOWN is handled to release refs to cached dsts
>   */
>  static int ip_vs_dst_event(struct notifier_block *this, unsigned long event,
>  			    void *ptr)
> @@ -1527,7 +1525,7 @@ static int ip_vs_dst_event(struct notifier_block *this, unsigned long event,
>  	struct ip_vs_dest *dest;
>  	unsigned int idx;
>  
> -	if (event != NETDEV_UNREGISTER || !ipvs)
> +	if (event != NETDEV_DOWN || !ipvs)
>  		return NOTIFY_DONE;
>  	IP_VS_DBG(3, "%s() dev=%s\n", __func__, dev->name);
>  	EnterFunction(2);

Regards
Hans