vls: relax copy on fork locks

Change-Id: I08cb7180364a5ef8444c9895c6d4f4842661b2a7
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/vcl/vcl_locked.c b/src/vcl/vcl_locked.c
index 5539191..3b6817c 100644
--- a/src/vcl/vcl_locked.c
+++ b/src/vcl/vcl_locked.c
@@ -397,7 +397,7 @@
   wrk->sessions = pool_dup (parent_wrk->sessions);
   wrk->session_index_by_vpp_handles =
     hash_dup (parent_wrk->session_index_by_vpp_handles);
-  vls_table_wlock ();
+  vls_table_rlock ();
 
   /* *INDENT-OFF* */
   pool_foreach (s, wrk->sessions, ({
@@ -405,7 +405,7 @@
   }));
   /* *INDENT-ON* */
 
-  vls_table_wunlock ();
+  vls_table_runlock ();
 }
 
 static void