From cc3a5ae6f23336ddc1d136a66c0a6a60276e99a3 Mon Sep 17 00:00:00 2001 From: Andy Zhou Date: Mon, 8 Sep 2014 13:14:22 -0700 Subject: [PATCH] openvswitch: Refactor get_dp() function into multiple access APIs. Avoid recursive read_rcu_lock() by using the lighter weight get_dp_rcu() API. Add proper locking assertions to get_dp(). Signed-off-by: Andy Zhou Signed-off-by: Pravin B Shelar --- net/openvswitch/datapath.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index bbb920bf48da..cdbc44c18714 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -140,19 +140,30 @@ static int queue_gso_packets(struct datapath *dp, struct sk_buff *, static int queue_userspace_packet(struct datapath *dp, struct sk_buff *, const struct dp_upcall_info *); -/* Must be called with rcu_read_lock or ovs_mutex. */ -static struct datapath *get_dp(struct net *net, int dp_ifindex) +/* Must be called with rcu_read_lock. */ +static struct datapath *get_dp_rcu(struct net *net, int dp_ifindex) { - struct datapath *dp = NULL; - struct net_device *dev; + struct net_device *dev = dev_get_by_index_rcu(net, dp_ifindex); - rcu_read_lock(); - dev = dev_get_by_index_rcu(net, dp_ifindex); if (dev) { struct vport *vport = ovs_internal_dev_get_vport(dev); if (vport) - dp = vport->dp; + return vport->dp; } + + return NULL; +} + +/* The caller must hold either ovs_mutex or rcu_read_lock to keep the + * returned dp pointer valid. + */ +static inline struct datapath *get_dp(struct net *net, int dp_ifindex) +{ + struct datapath *dp; + + WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held()); + rcu_read_lock(); + dp = get_dp_rcu(net, dp_ifindex); rcu_read_unlock(); return dp; @@ -573,7 +584,7 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info) packet->mark = flow->key.phy.skb_mark; rcu_read_lock(); - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex); err = -ENODEV; if (!dp) goto err_unlock; @@ -1227,7 +1238,7 @@ static int ovs_flow_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb) struct datapath *dp; rcu_read_lock(); - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex); if (!dp) { rcu_read_unlock(); return -ENODEV; @@ -1989,7 +2000,7 @@ static int ovs_vport_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb) int i, j = 0; rcu_read_lock(); - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex); if (!dp) { rcu_read_unlock(); return -ENODEV; -- 2.20.1