Re: [B.A.T.M.A.N.] [PATCH 4/4] batman-adv: debugfs: Add netns support

[Antonio Quartulli <a@unstable.cc>]

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On Wed, Jan 20, 2016 at 06:48:30PM +0100, Andrew Lunn wrote:

[...]

> +static DEFINE_MUTEX(batadv_debugfs_ns_mutex);

[...]

> +static void batadv_debugfs_ns_put(struct net *net)
> +{
> +	struct batadv_debugfs_ns_entry *ns_entry;
> +
> +	mutex_lock(&batadv_debugfs_ns_mutex);
> +	list_for_each_entry(ns_entry, &batadv_debugfs_ns, link) {
> +		if (ns_entry->net == net) {
> +			kref_put(&ns_entry->refcount, batadv_ns_entry_release);
> +			break;
> +		}
> +	}
> +	mutex_unlock(&batadv_debugfs_ns_mutex);
> +}
>  

Andrew, is there any particular reason why in this case we use a mutex instead
of a spinlock + RCU ? I imagine it is something related to debugfs..or just to
make the code simpler as we don't really require a full-blown RCU strategy ?



>  int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
>  {
> +	char *name = hard_iface->net_dev->name;
> +	struct net *net = dev_net(hard_iface->net_dev);

here we should respect David's inverted Christmas tree rule :)

>  	struct batadv_debuginfo **bat_debug;
> +	struct dentry *debugfs_ns_dir;
>  	struct dentry *file;
>  
>  	if (!batadv_debugfs)
>  		goto out;
>  
> -	hard_iface->debug_dir = debugfs_create_dir(hard_iface->net_dev->name,
> -						   batadv_debugfs);

how about:

	debugfs_ns_dir = batadv_debugfs;

> +	if (net != &init_net) {
> +		debugfs_ns_dir = batadv_debugfs_ns_get(net);
> +		if (!debugfs_ns_dir)
> +			goto out;
	}

	hard_iface->debug_dir = debugfs_create_dir(name, debugfs_ns_dir);

isn't it nicer? :)


>  	if (!hard_iface->debug_dir)
>  		goto out;
>  

[...]

> -	bat_priv->debug_dir = debugfs_create_dir(dev->name, batadv_debugfs);
> +	if (net != &init_net) {
> +		debugfs_ns_dir = batadv_debugfs_ns_get(net);
> +		if (!debugfs_ns_dir)
> +			goto out;
> +		bat_priv->debug_dir = debugfs_create_dir(dev->name,
> +							 debugfs_ns_dir);
> +	} else {
> +		bat_priv->debug_dir = debugfs_create_dir(dev->name,
> +							 batadv_debugfs);
> +	}

same as above


> +
>  	if (!bat_priv->debug_dir)
>  		goto out;
>  



-- 
Antonio Quartulli

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