Subject: Re: [PATCH] ks8851_ml ethernet network driver

From: Stephen Hemminger <[email-masked]>
Date: Wed, 16 Sep 2009 21:07:02 -0700

On Wed, 16 Sep 2009 19:38:36 -0700
Greg KH <[email-masked]> wrote:

> +
> +/**
> + * ks_net_open - open network device
> + * @netdev: The network device being opened.
> + *
> + * Called when the network device is marked active, such as a user executing
> + * 'ifconfig up' on the device.
> + */
> +static int ks_net_open(struct net_device *netdev)
> +{
> +	struct ks_net *ks = netdev_priv(netdev);
> +	int err;
> +
> +#define	KS_INT_FLAGS	(IRQF_DISABLED|IRQF_TRIGGER_LOW)
> +	/* lock the card, even if we may not actually do anything
> +	 * else at the moment.
> +	 */
> +	mutex_lock(&ks->lock);
> +

I don't understand the purpose of ks->lock mutex. What is it
really protecting? open/close are already protected by rtnl_mutex,
is it really only for the PHY?