Revert "p2p: use atomic types (ethereum#27764)"

This reverts commit f438ff5.

p2p/message.go

@@ -156,7 +156,7 @@ func MsgPipe() (*MsgPipeRW, *MsgPipeRW) {
 	var (
 		c1, c2  = make(chan Msg), make(chan Msg)
 		closing = make(chan struct{})
-		closed  = new(atomic.Bool)
+		closed  = new(int32)
 		rw1     = &MsgPipeRW{c1, c2, closing, closed}
 		rw2     = &MsgPipeRW{c2, c1, closing, closed}
 	)
@@ -172,13 +172,13 @@ type MsgPipeRW struct {
 	w       chan<- Msg
 	r       <-chan Msg
 	closing chan struct{}
-	closed  *atomic.Bool
+	closed  *int32
 }
 
 // WriteMsg sends a message on the pipe.
 // It blocks until the receiver has consumed the message payload.
 func (p *MsgPipeRW) WriteMsg(msg Msg) error {
-	if !p.closed.Load() {
+	if atomic.LoadInt32(p.closed) == 0 {
 		consumed := make(chan struct{}, 1)
 		msg.Payload = &eofSignal{msg.Payload, msg.Size, consumed}
 		select {
@@ -199,7 +199,7 @@ func (p *MsgPipeRW) WriteMsg(msg Msg) error {
 
 // ReadMsg returns a message sent on the other end of the pipe.
 func (p *MsgPipeRW) ReadMsg() (Msg, error) {
-	if !p.closed.Load() {
+	if atomic.LoadInt32(p.closed) == 0 {
 		select {
 		case msg := <-p.r:
 			return msg, nil
@@ -213,8 +213,9 @@ func (p *MsgPipeRW) ReadMsg() (Msg, error) {
 // of the pipe. They will return ErrPipeClosed. Close also
 // interrupts any reads from a message payload.
 func (p *MsgPipeRW) Close() error {
-	if p.closed.Swap(true) {
+	if atomic.AddInt32(p.closed, 1) != 1 {
 		// someone else is already closing
+		atomic.StoreInt32(p.closed, 1) // avoid overflow
 		return nil
 	}
 	close(p.closing)