[Patch net-next v3] net: fix some RCU warnings in various places

[Patch net-next v3] net: fix some RCU warnings in various places

[Cong Wang]

From: Cong Wang <amwang@redhat.com>

This fixes sparse warnings like the one below:

drivers/net/team/team.c:953:25: warning: incorrect type in return expression (different address spaces)
drivers/net/team/team.c:953:25:    expected struct netpoll_info *
drivers/net/team/team.c:953:25:    got struct netpoll_info [noderef] <asn:4>*npinfo

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Vlad Yasevich <vyasevic@redhat.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>

---
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 94c1534..71ad0f2 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1302,7 +1302,7 @@ static int bond_netpoll_setup(struct net_device *dev, struct netpoll_info *ni, g
 
 static struct netpoll_info *bond_netpoll_info(struct bonding *bond)
 {
-	return bond->dev->npinfo;
+	return rcu_access_pointer(bond->dev->npinfo);
 }
 
 #else
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index 05c5efe..03e5949 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -950,7 +950,7 @@ static void team_port_disable_netpoll(struct team_port *port)
 
 static struct netpoll_info *team_netpoll_info(struct team *team)
 {
-	return team->dev->npinfo;
+	return rcu_access_pointer(team->dev->npinfo);
 }
 
 #else
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 6d314c4..0aa1b84 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -330,7 +330,7 @@ extern netdev_tx_t br_dev_xmit(struct sk_buff *skb,
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static inline struct netpoll_info *br_netpoll_info(struct net_bridge *br)
 {
-	return br->dev->npinfo;
+	return rcu_access_pointer(br->dev->npinfo);
 }
 
 static inline void br_netpoll_send_skb(const struct net_bridge_port *p,
@@ -469,7 +469,7 @@ extern void br_multicast_free_pg(struct rcu_head *head);
 extern struct net_bridge_port_group *br_multicast_new_port_group(
 				struct net_bridge_port *port,
 				struct br_ip *group,
-				struct net_bridge_port_group *next,
+				struct net_bridge_port_group __rcu *next,
 				unsigned char state);
 extern void br_mdb_init(void);
 extern void br_mdb_uninit(void);

Re: [Patch net-next v3] net: fix some RCU warnings in various places

[Eric Dumazet]

On Sat, 2013-02-16 at 13:48 +0800, Cong Wang wrote:
> From: Cong Wang <amwang@redhat.com>
> 
> This fixes sparse warnings like the one below:

>  static inline void br_netpoll_send_skb(const struct net_bridge_port *p,
> @@ -469,7 +469,7 @@ extern void br_multicast_free_pg(struct rcu_head *head);
>  extern struct net_bridge_port_group *br_multicast_new_port_group(
>  				struct net_bridge_port *port,
>  				struct br_ip *group,
> -				struct net_bridge_port_group *next,
> +				struct net_bridge_port_group __rcu *next,
>  				unsigned char state);
>  extern void br_mdb_init(void);
>  extern void br_mdb_uninit(void);

This part is wrong, please remove the __rcu annotation in function
definition.

To perform " rcu_assign_pointer(p->next, next); ", there is no need to
annotate "next" with __rcu

Re: [Patch net-next v3] net: fix some RCU warnings in various places

[Cong Wang]

On Fri, 2013-02-15 at 22:23 -0800, Eric Dumazet wrote:
> On Sat, 2013-02-16 at 13:48 +0800, Cong Wang wrote:
> > From: Cong Wang <amwang@redhat.com>
> > 
> > This fixes sparse warnings like the one below:
> 
> >  static inline void br_netpoll_send_skb(const struct net_bridge_port *p,
> > @@ -469,7 +469,7 @@ extern void br_multicast_free_pg(struct rcu_head *head);
> >  extern struct net_bridge_port_group *br_multicast_new_port_group(
> >  				struct net_bridge_port *port,
> >  				struct br_ip *group,
> > -				struct net_bridge_port_group *next,
> > +				struct net_bridge_port_group __rcu *next,
> >  				unsigned char state);
> >  extern void br_mdb_init(void);
> >  extern void br_mdb_uninit(void);
> 
> This part is wrong, please remove the __rcu annotation in function
> definition.
> 
> To perform " rcu_assign_pointer(p->next, next); ", there is no need to
> annotate "next" with __rcu
> 

This will introduce more warnings, enjoy. ;)

So I will leave this to Vlad.

Thanks.