Remove unnecessary locking from functions that are always called with
appropriate locking and add/fix comments about locking requirements.

Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
---
 datapath/datapath.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 58e20be..f97725e 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -175,6 +175,7 @@ static struct hlist_head *vport_hash_bucket(const struct 
datapath *dp,
        return &dp->ports[port_no & (DP_VPORT_HASH_BUCKETS - 1)];
 }
 
+/* Called with ovs_mutex or RCU read lock. */
 struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no)
 {
        struct vport *vport;
@@ -650,7 +651,7 @@ static size_t ovs_flow_cmd_msg_size(const struct 
sw_flow_actions *acts)
                + nla_total_size(acts->actions_len); /* OVS_FLOW_ATTR_ACTIONS */
 }
 
-/* Called with ovs_mutex. */
+/* Called with ovs_mutex or RCU read lock. */
 static int ovs_flow_cmd_fill_info(struct sw_flow *flow, struct datapath *dp,
                                  struct sk_buff *skb, u32 portid,
                                  u32 seq, u32 flags, u8 cmd)
@@ -741,6 +742,7 @@ error:
        return err;
 }
 
+/* Must be called with ovs_mutex. */
 static struct sk_buff *ovs_flow_cmd_alloc_info(struct sw_flow *flow,
                                               struct genl_info *info)
 {
@@ -751,6 +753,7 @@ static struct sk_buff *ovs_flow_cmd_alloc_info(struct 
sw_flow *flow,
        return genlmsg_new_unicast(len, info, GFP_KERNEL);
 }
 
+/* Must be called with ovs_mutex. */
 static struct sk_buff *ovs_flow_cmd_build_info(struct sw_flow *flow,
                                               struct datapath *dp,
                                               struct genl_info *info,
@@ -1098,6 +1101,7 @@ static size_t ovs_dp_cmd_msg_size(void)
        return msgsize;
 }
 
+/* Called with ovs_mutex or RCU read lock. */
 static int ovs_dp_cmd_fill_info(struct datapath *dp, struct sk_buff *skb,
                                u32 portid, u32 seq, u32 flags, u8 cmd)
 {
@@ -1113,9 +1117,7 @@ static int ovs_dp_cmd_fill_info(struct datapath *dp, 
struct sk_buff *skb,
 
        ovs_header->dp_ifindex = get_dpifindex(dp);
 
-       rcu_read_lock();
        err = nla_put_string(skb, OVS_DP_ATTR_NAME, ovs_dp_name(dp));
-       rcu_read_unlock();
        if (err)
                goto nla_put_failure;
 
@@ -1140,6 +1142,7 @@ error:
        return -EMSGSIZE;
 }
 
+/* Must be called with ovs_mutex. */
 static struct sk_buff *ovs_dp_cmd_build_info(struct datapath *dp,
                                             struct genl_info *info, u8 cmd)
 {
@@ -1158,7 +1161,7 @@ static struct sk_buff *ovs_dp_cmd_build_info(struct 
datapath *dp,
        return skb;
 }
 
-/* Called with ovs_mutex. */
+/* Called with rcu_read_lock or ovs_mutex. */
 static struct datapath *lookup_datapath(struct net *net,
                                        struct ovs_header *ovs_header,
                                        struct nlattr *a[OVS_DP_ATTR_MAX + 1])
@@ -1170,10 +1173,8 @@ static struct datapath *lookup_datapath(struct net *net,
        else {
                struct vport *vport;
 
-               rcu_read_lock();
                vport = ovs_vport_locate(net, nla_data(a[OVS_DP_ATTR_NAME]));
                dp = vport && vport->port_no == OVSP_LOCAL ? vport->dp : NULL;
-               rcu_read_unlock();
        }
        return dp ? dp : ERR_PTR(-ENODEV);
 }
-- 
1.7.10.4

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