Subject: Re: [PATCH 2/2] ipvs: generalize app registration in netns

From: Pablo Neira Ayuso <[email-masked]>
Date: Thu, 12 Jul 2012 18:22:09 +0200

On Wed, Jul 11, 2012 at 09:25:27AM +0900, Simon Horman wrote:
> From: Julian Anastasov <[email-masked]>
> 
> 	Get rid of the ftp_app pointer and allow applications
> to be registered without adding fields in the netns_ipvs structure.
> 
> Signed-off-by: Julian Anastasov <[email-masked]>
> Signed-off-by: Simon Horman <[email-masked]>
> ---
>  include/net/ip_vs.h            |  5 ++--
>  net/netfilter/ipvs/ip_vs_app.c | 61 +++++++++++++++++++++++++++++++-----------
>  net/netfilter/ipvs/ip_vs_ftp.c | 21 ++++-----------
>  3 files changed, 52 insertions(+), 35 deletions(-)
> 
> diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
> index d6146b4..6cb4699 100644
> --- a/include/net/ip_vs.h
> +++ b/include/net/ip_vs.h
> @@ -808,8 +808,6 @@ struct netns_ipvs {
>  	struct list_head	rs_table[IP_VS_RTAB_SIZE];
>  	/* ip_vs_app */
>  	struct list_head	app_list;
> -	/* ip_vs_ftp */
> -	struct ip_vs_app	*ftp_app;
>  	/* ip_vs_proto */
>  	#define IP_VS_PROTO_TAB_SIZE	32	/* must be power of 2 */
>  	struct ip_vs_proto_data *proto_data_table[IP_VS_PROTO_TAB_SIZE];
> @@ -1179,7 +1177,8 @@ extern void ip_vs_service_net_cleanup(struct net *net);
>   *      (from ip_vs_app.c)
>   */
>  #define IP_VS_APP_MAX_PORTS  8
> -extern int register_ip_vs_app(struct net *net, struct ip_vs_app *app);
> +extern struct ip_vs_app *register_ip_vs_app(struct net *net,
> +					    struct ip_vs_app *app);
>  extern void unregister_ip_vs_app(struct net *net, struct ip_vs_app *app);
>  extern int ip_vs_bind_app(struct ip_vs_conn *cp, struct ip_vs_protocol *pp);
>  extern void ip_vs_unbind_app(struct ip_vs_conn *cp);
> diff --git a/net/netfilter/ipvs/ip_vs_app.c b/net/netfilter/ipvs/ip_vs_app.c
> index 64f9e8f..11caaea 100644
> --- a/net/netfilter/ipvs/ip_vs_app.c
> +++ b/net/netfilter/ipvs/ip_vs_app.c
> @@ -180,22 +180,41 @@ register_ip_vs_app_inc(struct net *net, struct ip_vs_app *app, __u16 proto,
>  }
>  
>  
> -/*
> - *	ip_vs_app registration routine
> - */
> -int register_ip_vs_app(struct net *net, struct ip_vs_app *app)
> +/* Register application for netns */
> +struct ip_vs_app *register_ip_vs_app(struct net *net, struct ip_vs_app *app)
>  {
>  	struct netns_ipvs *ipvs = net_ipvs(net);
> -	/* increase the module use count */
> -	ip_vs_use_count_inc();
> +	struct ip_vs_app *a;
> +	int err = 0;
> +
> +	if (!ipvs)
> +		return ERR_PTR(-ENOENT);
>  
>  	mutex_lock(&__ip_vs_app_mutex);
>  
> -	list_add(&app->a_list, &ipvs->app_list);
> +	list_for_each_entry(a, &ipvs->app_list, a_list) {
> +		if (!strcmp(app->name, a->name)) {
> +			err = -EEXIST;
> +			break;
> +		}
> +	}
> +	if (!err) {
> +		a = kmemdup(app, sizeof(*app), GFP_KERNEL);
> +		if (!a)
> +			err = -ENOMEM;
> +	}
> +	if (!err) {
> +		INIT_LIST_HEAD(&a->incs_list);
> +		list_add(&a->a_list, &ipvs->app_list);
> +		/* increase the module use count */
> +		ip_vs_use_count_inc();
> +	}

I think this code will look better if you use something like:

+		if (!strcmp(app->name, a->name)) {
+			err = -EEXIST;
+			goto err_unlock;
+		}

err_unlock:
        mutex_unlock(...)

>  
>  	mutex_unlock(&__ip_vs_app_mutex);
>  
> -	return 0;
> +	if (err)
> +		return ERR_PTR(err);
> +	return a;

For this three lines above, you can use:

return err ? return ERR_PTR(err) : a;

>  }
>  
>  
> @@ -205,20 +224,29 @@ int register_ip_vs_app(struct net *net, struct ip_vs_app *app)
>   */
>  void unregister_ip_vs_app(struct net *net, struct ip_vs_app *app)
>  {
> -	struct ip_vs_app *inc, *nxt;
> +	struct netns_ipvs *ipvs = net_ipvs(net);
> +	struct ip_vs_app *a, *anxt, *inc, *nxt;
> +
> +	if (!ipvs)
> +		return;
>  
>  	mutex_lock(&__ip_vs_app_mutex);
>  
> -	list_for_each_entry_safe(inc, nxt, &app->incs_list, a_list) {
> -		ip_vs_app_inc_release(net, inc);
> -	}
> +	list_for_each_entry_safe(a, anxt, &ipvs->app_list, a_list) {
> +		if (app && strcmp(app->name, a->name))
> +			continue;
> +		list_for_each_entry_safe(inc, nxt, &a->incs_list, a_list) {
> +			ip_vs_app_inc_release(net, inc);
> +		}
>  
> -	list_del(&app->a_list);
> +		list_del(&a->a_list);
> +		kfree(a);
>  
> -	mutex_unlock(&__ip_vs_app_mutex);
> +		/* decrease the module use count */
> +		ip_vs_use_count_dec();
> +	}
>  
> -	/* decrease the module use count */
> -	ip_vs_use_count_dec();
> +	mutex_unlock(&__ip_vs_app_mutex);
>  }
>  
>  
> @@ -586,5 +614,6 @@ int __net_init ip_vs_app_net_init(struct net *net)
>  
>  void __net_exit ip_vs_app_net_cleanup(struct net *net)
>  {
> +	unregister_ip_vs_app(net, NULL /* all */);
>  	proc_net_remove(net, "ip_vs_app");
>  }
> diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
> index b20b29c..ad70b7e 100644
> --- a/net/netfilter/ipvs/ip_vs_ftp.c
> +++ b/net/netfilter/ipvs/ip_vs_ftp.c
> @@ -441,16 +441,10 @@ static int __net_init __ip_vs_ftp_init(struct net *net)
>  
>  	if (!ipvs)
>  		return -ENOENT;
> -	app = kmemdup(&ip_vs_ftp, sizeof(struct ip_vs_app), GFP_KERNEL);
> -	if (!app)
> -		return -ENOMEM;
> -	INIT_LIST_HEAD(&app->a_list);
> -	INIT_LIST_HEAD(&app->incs_list);
> -	ipvs->ftp_app = app;
>  
> -	ret = register_ip_vs_app(net, app);
> -	if (ret)
> -		goto err_exit;
> +	app = register_ip_vs_app(net, &ip_vs_ftp);
> +	if (IS_ERR(app))
> +		return PTR_ERR(app);
>  
>  	for (i = 0; i < ports_count; i++) {
>  		if (!ports[i])
> @@ -464,9 +458,7 @@ static int __net_init __ip_vs_ftp_init(struct net *net)
>  	return 0;
>  
>  err_unreg:
> -	unregister_ip_vs_app(net, app);
> -err_exit:
> -	kfree(ipvs->ftp_app);
> +	unregister_ip_vs_app(net, &ip_vs_ftp);
>  	return ret;
>  }
>  /*
> @@ -474,10 +466,7 @@ err_exit:
>   */
>  static void __ip_vs_ftp_exit(struct net *net)
>  {
> -	struct netns_ipvs *ipvs = net_ipvs(net);
> -
> -	unregister_ip_vs_app(net, ipvs->ftp_app);
> -	kfree(ipvs->ftp_app);
> +	unregister_ip_vs_app(net, &ip_vs_ftp);
>  }
>  
>  static struct pernet_operations ip_vs_ftp_ops = {
> -- 
> 1.7.10.2.484.gcd07cc5
> 
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