linux-kernel - Re: [PATCH, resend] netconsole: take care of NETDEV

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Message-Id: <1241110115.938.1603.camel@calx>
Date:	Thu, 30 Apr 2009 11:48:35 -0500
From:	Matt Mackall <mpm@...enic.com>
To:	Bruno Prémont <bonbons@...ux-vserver.org>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH, resend] netconsole: take care of NETDEV_UNREGISTER
 event

On Thu, 2009-04-30 at 08:45 +0200, Bruno Prémont wrote:
> When netconsole is loaded and a network interface fades away (e.g. on
> rmmod $interface_driver_module) the rmmod remains stuck and some locks
> are taken that prevent any additional module loading/unloading as well
> as interface up/down changes.
> In addition kernel logs (and console) get flooded at 10s interval with
> 
> [  122.464065] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
> [  132.704059] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
> 
> This patch lets netconsole take NETDEV_UNREGISTER event into account
> and release the affected interface if it was in use.
> 
> Signed-off-by: Bruno Prémont <bonbons@...ux-vserver.org>

Acked-by: Matt Mackall <mpm@...enic.com>

> ---
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index eceadf7..bf4af52 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -664,7 +664,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
>  	struct netconsole_target *nt;
>  	struct net_device *dev = ptr;
>  
> -	if (!(event == NETDEV_CHANGENAME))
> +	if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER))
>  		goto done;
>  
>  	spin_lock_irqsave(&target_list_lock, flags);
> @@ -675,6 +675,15 @@ static int netconsole_netdev_event(struct notifier_block *this,
>  			case NETDEV_CHANGENAME:
>  				strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
>  				break;
> +			case NETDEV_UNREGISTER:
> +				if (!nt->enabled)
> +					break;
> +				netpoll_cleanup(&nt->np);
> +				nt->enabled = 0;
> +				printk(KERN_INFO "netconsole: network logging stopped"
> +					", interface %s unregistered\n",
> +					dev->name);
> +				break;
>  			}
>  		}
>  		netconsole_target_put(nt);
> --
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-- 
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