Revert "p2p: move ping handling into pingLoop goroutine (#27887)"

This reverts commit 951c49dcf0.

p2p/peer.go

@@ -112,7 +112,6 @@ type Peer struct {
 	wg       sync.WaitGroup
 	protoErr chan error
 	closed   chan struct{}
-	pingRecv chan struct{}
 	disc     chan DiscReason
 
 	// events receives message send / receive events if set
@@ -234,7 +233,6 @@ func newPeer(log log.Logger, conn *conn, protocols []Protocol) *Peer {
 		disc:     make(chan DiscReason),
 		protoErr: make(chan error, len(protomap)+1), // protocols + pingLoop
 		closed:   make(chan struct{}),
-		pingRecv: make(chan struct{}, 16),
 		log:      log.New("id", conn.node.ID(), "conn", conn.flags),
 	}
 	return p
@@ -295,11 +293,9 @@ loop:
 }
 
 func (p *Peer) pingLoop() {
-	defer p.wg.Done()
-
 	ping := time.NewTimer(pingInterval)
+	defer p.wg.Done()
 	defer ping.Stop()
-
 	for {
 		select {
 		case <-ping.C:
@@ -308,10 +304,6 @@ func (p *Peer) pingLoop() {
 				return
 			}
 			ping.Reset(pingInterval)
-
-		case <-p.pingRecv:
-			SendItems(p.rw, pongMsg)
-
 		case <-p.closed:
 			return
 		}
@@ -338,10 +330,7 @@ func (p *Peer) handle(msg Msg) error {
 	switch {
 	case msg.Code == pingMsg:
 		msg.Discard()
-		select {
-		case p.pingRecv <- struct{}{}:
-		case <-p.closed:
-		}
+		go SendItems(p.rw, pongMsg)
 	case msg.Code == discMsg:
 		// This is the last message. We don't need to discard or
 		// check errors because, the connection will be closed after it.