openvswitch: Use RCU lock for flow dump operation.
Flow dump operation is read-only operation. There is no need to
take ovs-lock. Following patch use rcu-lock for dumping flows.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index f2ed760..e6fb866 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1104,7 +1104,6 @@
u32 seq, u32 flags, u8 cmd)
{
const int skb_orig_len = skb->len;
- const struct sw_flow_actions *sf_acts;
struct nlattr *start;
struct ovs_flow_stats stats;
struct ovs_header *ovs_header;
@@ -1113,8 +1112,6 @@
u8 tcp_flags;
int err;
- sf_acts = ovsl_dereference(flow->sf_acts);
-
ovs_header = genlmsg_put(skb, portid, seq, &dp_flow_genl_family, flags, cmd);
if (!ovs_header)
return -EMSGSIZE;
@@ -1161,6 +1158,11 @@
*/
start = nla_nest_start(skb, OVS_FLOW_ATTR_ACTIONS);
if (start) {
+ const struct sw_flow_actions *sf_acts;
+
+ sf_acts = rcu_dereference_check(flow->sf_acts,
+ lockdep_ovsl_is_held());
+
err = actions_to_attr(sf_acts->actions, sf_acts->actions_len, skb);
if (!err)
nla_nest_end(skb, start);
@@ -1440,15 +1442,14 @@
struct datapath *dp;
struct flow_table *table;
- ovs_lock();
+ rcu_read_lock();
dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
if (!dp) {
- ovs_unlock();
+ rcu_read_unlock();
return -ENODEV;
}
- table = ovsl_dereference(dp->table);
-
+ table = rcu_dereference(dp->table);
for (;;) {
struct sw_flow *flow;
u32 bucket, obj;
@@ -1468,7 +1469,7 @@
cb->args[0] = bucket;
cb->args[1] = obj;
}
- ovs_unlock();
+ rcu_read_unlock();
return skb->len;
}