datapath/flow: Fix ovs_flow_stats_get/clear RCU dereference.

For ovs_flow_stats_get() using ovsl_dereference() was wrong, since flow dumps call this with RCU read lock. ovs_flow_stats_clear() is always called with ovs_mutex, so can use ovsl_dereference(). Also, make the ovs_flow_stats_get() 'flow' argument const to make later patches cleaner. Signed-off-by: Jarno Rajahalme <[email protected]> Signed-off-by: Pravin B Shelar <[email protected]>
little-dude · Apr 2, 2014 · 4bb90be · 4bb90be
1 parent 87e6ccf
commit 4bb90be
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Showing 2 changed files with 9 additions and 7 deletions.
diff --git a/datapath/flow.c b/datapath/flow.c
@@ -123,8 +123,9 @@ void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb)
 	spin_unlock(&stats->lock);
 }
 
-/* Called with ovs_mutex. */
-void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
+/* Must be called with rcu_read_lock or ovs_mutex. */
+void ovs_flow_stats_get(const struct sw_flow *flow,
+			struct ovs_flow_stats *ovs_stats,
 			unsigned long *used, __be16 *tcp_flags)
 {
 	int node;
@@ -134,7 +135,7 @@ void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 	memset(ovs_stats, 0, sizeof(*ovs_stats));
 
 	for_each_node(node) {
-		struct flow_stats *stats = ovsl_dereference(flow->stats[node]);
+		struct flow_stats *stats = rcu_dereference_ovsl(flow->stats[node]);
 
 		if (stats) {
 			/* Local CPU may write on non-local stats, so we must
@@ -151,12 +152,13 @@ void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 	}
 }
 
+/* Called with ovs_mutex. */
 void ovs_flow_stats_clear(struct sw_flow *flow)
 {
 	int node;
 
 	for_each_node(node) {
-		struct flow_stats *stats = rcu_dereference(flow->stats[node]);
+		struct flow_stats *stats = ovsl_dereference(flow->stats[node]);
 
 		if (stats) {
 			spin_lock_bh(&stats->lock);

diff --git a/datapath/flow.h b/datapath/flow.h
@@ -182,10 +182,10 @@ struct arp_eth_header {
 	unsigned char       ar_tip[4];		/* target IP address        */
 } __packed;
 
-void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb);
-void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *stats,
+void ovs_flow_stats_update(struct sw_flow *, struct sk_buff *);
+void ovs_flow_stats_get(const struct sw_flow *, struct ovs_flow_stats *,
 			unsigned long *used, __be16 *tcp_flags);
-void ovs_flow_stats_clear(struct sw_flow *flow);
+void ovs_flow_stats_clear(struct sw_flow *);
 u64 ovs_flow_used_time(unsigned long flow_jiffies);
 
 int ovs_flow_extract(struct sk_buff *, u16 in_port, struct sw_flow_key *);