Add missing locks in Agent UVE code

(1)Acquire lock in VnUveEntry::ClearInterVnStats to prevent parallel access to
inter_vn_stats_ between kTaskFlowStatsCollector and kTaskDBExclude
(2)Acquire lock in InterfaceUveStatsTable::FipEntry to prevent parallel access to
interface_tree_ between kTaskFlowStatsCollector and kTaskDBExclude

Partial-Bug: #1641833
(cherry picked from commit 006c5e6)

Change-Id: I5a319892421664c5be23d6a2dc228e6c94271d3a

src/vnsw/agent/uve/interface_uve_stats_table.cc

@@ -207,6 +207,7 @@ void InterfaceUveStatsTable::UpdatePortBitmap
 
 InterfaceUveTable::FloatingIp * InterfaceUveStatsTable::FipEntry
     (uint32_t fip, const string &vn, Interface *intf) {
+    tbb::mutex::scoped_lock lock(interface_tree_mutex_);
     VmInterface *vmi = static_cast<VmInterface *>(intf);
     InterfaceMap::iterator intf_it = interface_tree_.find(vmi->cfg_name());
 

src/vnsw/agent/uve/vn_uve_entry.cc

@@ -60,8 +60,9 @@ void VnUveEntry::UpdateInterVnStats(const string &dst_vn, uint64_t bytes,
     }
 }
 
+/* Remove all the elements of map entry value which is a set */
 void VnUveEntry::ClearInterVnStats() {
-    /* Remove all the elements of map entry value which is a set */
+    tbb::mutex::scoped_lock lock(mutex_);
     VnStatsSet::iterator stats_it = inter_vn_stats_.begin();
     VnStatsSet::iterator del_it;
     while(stats_it != inter_vn_stats_.end()) {

src/vnsw/agent/uve/vn_uve_entry.h

@@ -112,7 +112,12 @@ class VnUveEntry : public VnUveEntryBase {
     void BuildArpStats(const StatsManager::VrfStats *s,
                        UveVrfStats &vrf_stats) const;
 
-    /* For exclusion between kTaskFlowStatsCollector and Agent::Uve */
+    /* For exclusion between kTaskFlowStatsCollector and
+     * Agent::Uve/kTaskDBExclude. This is used to protect port_bitmap_ and
+     * inter_vn_stats_ from parallel access between
+     * 1. kTaskFlowStatsCollector and Agent::Uve
+     * 2. kTaskFlowStatsCollector and kTaskDBExclude
+     */
     tbb::mutex mutex_;
     uint64_t in_bytes_;
     uint64_t out_bytes_;