openvswitch: Simplify datapath locking.

Currently OVS uses combination of genl and rtnl lock to protect
datapath state.  This was done due to networking stack locking.
But this has complicated locking and there are few lock ordering
issues with new tunneling protocols.
Following patch simplifies locking by introducing new ovs mutex
and now this lock is used to protect entire ovs state.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

1 files changed, 47 insertions, 22 deletions

diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h
index 655beb1fe07..16b84069521 100644
--- a/net/openvswitch/datapath.h
+++ b/net/openvswitch/datapath.h
@@ -57,9 +57,9 @@ struct dp_stats_percpu {
  * struct datapath - datapath for flow-based packet switching
  * @rcu: RCU callback head for deferred destruction.
  * @list_node: Element in global 'dps' list.
- * @table: Current flow table.  Protected by genl_lock and RCU.
+ * @table: Current flow table.  Protected by ovs_mutex and RCU.
  * @ports: Hash table for ports.  %OVSP_LOCAL port always exists.  Protected by
- * RTNL and RCU.
+ * ovs_mutex and RCU.
  * @stats_percpu: Per-CPU datapath statistics.
  * @net: Reference to net namespace.
  *
@@ -85,26 +85,6 @@ struct datapath {
 #endif
 };
 
-struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no);
-
-static inline struct vport *ovs_vport_rcu(const struct datapath *dp, int port_no)
-{
-	WARN_ON_ONCE(!rcu_read_lock_held());
-	return ovs_lookup_vport(dp, port_no);
-}
-
-static inline struct vport *ovs_vport_rtnl_rcu(const struct datapath *dp, int port_no)
-{
-	WARN_ON_ONCE(!rcu_read_lock_held() && !rtnl_is_locked());
-	return ovs_lookup_vport(dp, port_no);
-}
-
-static inline struct vport *ovs_vport_rtnl(const struct datapath *dp, int port_no)
-{
-	ASSERT_RTNL();
-	return ovs_lookup_vport(dp, port_no);
-}
-
 /**
  * struct ovs_skb_cb - OVS data in skb CB
  * @flow: The flow associated with this packet.  May be %NULL if no flow.
@@ -131,6 +111,30 @@ struct dp_upcall_info {
 	u32 portid;
 };
 
+/**
+ * struct ovs_net - Per net-namespace data for ovs.
+ * @dps: List of datapaths to enable dumping them all out.
+ * Protected by genl_mutex.
+ */
+struct ovs_net {
+	struct list_head dps;
+	struct work_struct dp_notify_work;
+};
+
+extern int ovs_net_id;
+void ovs_lock(void);
+void ovs_unlock(void);
+
+#ifdef CONFIG_LOCKDEP
+int lockdep_ovsl_is_held(void);
+#else
+#define lockdep_ovsl_is_held()	1
+#endif
+
+#define ASSERT_OVSL()		WARN_ON(unlikely(!lockdep_ovsl_is_held()))
+#define ovsl_dereference(p)					\
+	rcu_dereference_protected(p, lockdep_ovsl_is_held())
+
 static inline struct net *ovs_dp_get_net(struct datapath *dp)
 {
 	return read_pnet(&dp->net);
@@ -141,6 +145,26 @@ static inline void ovs_dp_set_net(struct datapath *dp, struct net *net)
 	write_pnet(&dp->net, net);
 }
 
+struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no);
+
+static inline struct vport *ovs_vport_rcu(const struct datapath *dp, int port_no)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	return ovs_lookup_vport(dp, port_no);
+}
+
+static inline struct vport *ovs_vport_ovsl_rcu(const struct datapath *dp, int port_no)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
+	return ovs_lookup_vport(dp, port_no);
+}
+
+static inline struct vport *ovs_vport_ovsl(const struct datapath *dp, int port_no)
+{
+	ASSERT_OVSL();
+	return ovs_lookup_vport(dp, port_no);
+}
+
 extern struct notifier_block ovs_dp_device_notifier;
 extern struct genl_multicast_group ovs_dp_vport_multicast_group;
 
@@ -154,4 +178,5 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 pid, u32 seq,
 					 u8 cmd);
 
 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb);
+void ovs_dp_notify_wq(struct work_struct *work);
 #endif /* datapath.h */