Ditch the torrent stateMu for the client mutex

client.go

@@ -1825,7 +1825,6 @@ func newTorrent(ih InfoHash) (t *torrent) {
 		HalfOpen:          make(map[string]struct{}),
 		pieceStateChanges: pubsub.NewPubSub(),
 	}
-	t.wantPeers.L = &t.stateMu
 	return
 }
 
@@ -2024,6 +2023,7 @@ func (cl *Client) AddTorrentSpec(spec *TorrentSpec) (T Torrent, new bool, err er
 		// TODO: Tidy this up?
 		t = newTorrent(spec.InfoHash)
 		t.cl = cl
+		t.wantPeers.L = &cl.mu
 		if spec.ChunkSize != 0 {
 			t.chunkSize = pp.Integer(spec.ChunkSize)
 		}
@@ -2087,8 +2087,6 @@ func (me *Client) dropTorrent(infoHash InfoHash) (err error) {
 func (cl *Client) waitWantPeers(t *torrent) bool {
 	cl.mu.Lock()
 	defer cl.mu.Unlock()
-	t.stateMu.Lock()
-	defer t.stateMu.Unlock()
 	for {
 		select {
 		case <-t.ceasingNetworking:
@@ -2102,11 +2100,7 @@ func (cl *Client) waitWantPeers(t *torrent) bool {
 			return true
 		}
 	wait:
-		cl.mu.Unlock()
 		t.wantPeers.Wait()
-		t.stateMu.Unlock()
-		cl.mu.Lock()
-		t.stateMu.Lock()
 	}
 }
 

t.go

@@ -48,14 +48,14 @@ func (t Torrent) NewReader() (ret *Reader) {
 // same state. The sum of the state run lengths is the number of pieces
 // in the torrent.
 func (t Torrent) PieceStateRuns() []PieceStateRun {
-	t.torrent.stateMu.Lock()
-	defer t.torrent.stateMu.Unlock()
+	t.cl.mu.Lock()
+	defer t.cl.mu.Unlock()
 	return t.torrent.pieceStateRuns()
 }
 
 func (t Torrent) PieceState(piece int) PieceState {
-	t.torrent.stateMu.Lock()
-	defer t.torrent.stateMu.Unlock()
+	t.cl.mu.Lock()
+	defer t.cl.mu.Unlock()
 	return t.torrent.pieceState(piece)
 }
 

torrent.go

@@ -51,11 +51,10 @@ type peersKey struct {
 	Port    int
 }
 
-// Is not aware of Client. Maintains state of torrent for with-in a Client.
+// Maintains state of torrent within a Client.
 type torrent struct {
 	cl *Client
 
-	stateMu sync.Mutex
 	closing chan struct{}
 
 	// Closed when no more network activity is desired. This includes
@@ -166,8 +165,6 @@ func (t *torrent) worstConns(cl *Client) (wcs *worstConns) {
 }
 
 func (t *torrent) ceaseNetworking() {
-	t.stateMu.Lock()
-	defer t.stateMu.Unlock()
 	select {
 	case <-t.ceasingNetworking:
 		return