SERVER-6018 The MSGID type doesn't need to be atomic

Author: acmorrow

src/mongo/util/net/message.cpp

@@ -53,7 +53,7 @@ namespace mongo {
         }
     }
 
-    MSGID NextMsgId;
+    AtomicWord<MSGID> NextMsgId;
 
     /*struct MsgStart {
         MsgStart() {
@@ -63,8 +63,7 @@ namespace mongo {
     } msgstart;*/
 
     MSGID nextMessageId() {
-        MSGID msgid = NextMsgId++;
-        return msgid;
+        return NextMsgId.fetchAndAdd(1);
     }
 
     bool doesOpGetAResponse( int op ) {

src/mongo/util/net/message.h

@@ -31,7 +31,8 @@
 
 #include <vector>
 
-#include "mongo/bson/util/atomic_int.h"
+#include "mongo/platform/atomic_word.h"
+#include "mongo/platform/cstdint.h"
 #include "mongo/util/goodies.h"
 #include "mongo/util/net/hostandport.h"
 #include "mongo/util/net/sock.h"
@@ -47,7 +48,7 @@ namespace mongo {
     class MessagingPort;
     class PiggyBackData;
 
-    typedef AtomicUInt MSGID;
+    typedef uint32_t MSGID;
 
     enum Operations {
         opReply = 1,     /* reply. responseTo is set. */

src/mongo/util/net/message_port.h

@@ -39,8 +39,6 @@ namespace mongo {
     class MessagingPort;
     class PiggyBackData;
 
-    typedef AtomicUInt MSGID;
-
     class AbstractMessagingPort : boost::noncopyable {
     public:
         AbstractMessagingPort() : tag(0), _connectionId(0) {}