replace unneeded RWMutex with Mutex

bitswap/client/internal/peermanager/peermanager.go

@@ -42,7 +42,7 @@ type PeerManager struct {
 	createPeerQueue PeerQueueFactory
 	ctx             context.Context
 
-	psLk         sync.RWMutex
+	psLk         sync.Mutex
 	sessions     map[uint64]Session
 	peerSessions map[peer.ID]map[uint64]struct{}
 

bitswap/client/internal/peermanager/peerwantmanager.go

@@ -158,8 +158,6 @@ func (pwm *peerWantManager) broadcastWantHaves(wantHaves []cid.Cid) {
 // sendWants only sends the peer the want-blocks and want-haves that have not
 // already been sent to it.
 func (pwm *peerWantManager) sendWants(p peer.ID, wantBlocks []cid.Cid, wantHaves []cid.Cid) {
-	fltWantBlks := make([]cid.Cid, 0, len(wantBlocks))
-	fltWantHvs := make([]cid.Cid, 0, len(wantHaves))
 
 	// Get the existing want-blocks and want-haves for the peer
 	pws, ok := pwm.peerWants[p]
@@ -169,6 +167,8 @@ func (pwm *peerWantManager) sendWants(p peer.ID, wantBlocks []cid.Cid, wantHaves
 		return
 	}
 
+	fltWantBlks := make([]cid.Cid, 0, len(wantBlocks))
+
 	// Iterate over the requested want-blocks
 	for _, c := range wantBlocks {
 		// If the want-block hasn't been sent to the peer
@@ -198,6 +198,8 @@ func (pwm *peerWantManager) sendWants(p peer.ID, wantBlocks []cid.Cid, wantHaves
 		pwm.reverseIndexAdd(c, p)
 	}
 
+	fltWantHvs := make([]cid.Cid, 0, len(wantHaves))
+
 	// Iterate over the requested want-haves
 	for _, c := range wantHaves {
 		// If we've already broadcasted this want, don't bother with a

bitswap/client/internal/session/sessionwants.go

@@ -159,11 +159,9 @@ func (sw *sessionWants) CancelPending(keys []cid.Cid) {
 
 // LiveWants returns a list of live wants
 func (sw *sessionWants) LiveWants() []cid.Cid {
-	live := make([]cid.Cid, len(sw.liveWants))
-	var i int
+	live := make([]cid.Cid, 0, len(sw.liveWants))
 	for c := range sw.liveWants {
-		live[i] = c
-		i++
+		live = append(live, c)
 	}
 
 	return live
@@ -188,7 +186,7 @@ func (sw *sessionWants) RandomLiveWant() cid.Cid {
 
 // Has live wants indicates if there are any live wants
 func (sw *sessionWants) HasLiveWants() bool {
-	return len(sw.liveWants) != 0
+	return len(sw.liveWants) > 0
 }
 
 // Indicates whether the want is in either of the fetch or live queues

bitswap/client/internal/session/sessionwantsender.go

@@ -269,7 +269,7 @@ func (sws *sessionWantSender) onChange(changes []change) {
 		if chng.update.from != "" {
 			// If the update includes blocks or haves, treat it as signaling that
 			// the peer is available
-			if len(chng.update.ks) != 0 || len(chng.update.haves) != 0 {
+			if len(chng.update.ks) > 0 || len(chng.update.haves) > 0 {
 				p := chng.update.from
 				availability[p] = true
 
@@ -295,7 +295,7 @@ func (sws *sessionWantSender) onChange(changes []change) {
 	sws.checkForExhaustedWants(dontHaves, newlyUnavailable)
 
 	// If there are any cancels, send them
-	if len(cancels) != 0 {
+	if len(cancels) > 0 {
 		sws.canceller.CancelSessionWants(sws.sessionID, cancels)
 	}
 
@@ -449,7 +449,7 @@ func (sws *sessionWantSender) processUpdates(updates []update) []cid.Cid {
 			}
 		}
 	}
-	if len(prunePeers) != 0 {
+	if len(prunePeers) > 0 {
 		go func() {
 			for p := range prunePeers {
 				// Peer doesn't have anything we want, so remove it
@@ -477,13 +477,11 @@ func (sws *sessionWantSender) checkForExhaustedWants(dontHaves []cid.Cid, newlyU
 
 	// If a peer just became unavailable, then we need to check all wants
 	// (because it may be the last peer who hadn't sent a DONT_HAVE for a CID)
-	if len(newlyUnavailable) != 0 {
+	if len(newlyUnavailable) > 0 {
 		// Collect all pending wants
-		wants = make([]cid.Cid, len(sws.wants))
-		var i int
+		wants = make([]cid.Cid, 0, len(sws.wants))
 		for c := range sws.wants {
-			wants[i] = c
-			i++
+			wants = append(wants, c)
 		}
 
 		// If the last available peer in the session has become unavailable
@@ -496,7 +494,7 @@ func (sws *sessionWantSender) checkForExhaustedWants(dontHaves []cid.Cid, newlyU
 
 	// If all available peers for a cid sent a DONT_HAVE, signal to the session
 	// that we've exhausted available peers
-	if len(wants) != 0 {
+	if len(wants) > 0 {
 		exhausted := sws.bpm.AllPeersDoNotHaveBlock(sws.spm.Peers(), wants)
 		sws.processExhaustedWants(exhausted)
 	}
@@ -506,7 +504,7 @@ func (sws *sessionWantSender) checkForExhaustedWants(dontHaves []cid.Cid, newlyU
 // already been marked as exhausted are passed to onPeersExhausted()
 func (sws *sessionWantSender) processExhaustedWants(exhausted []cid.Cid) {
 	newlyExhausted := sws.newlyExhausted(exhausted)
-	if len(newlyExhausted) != 0 {
+	if len(newlyExhausted) > 0 {
 		sws.onPeersExhausted(newlyExhausted)
 	}
 }

bitswap/client/internal/sessionmanager/sessionmanager.go

@@ -57,7 +57,7 @@ type SessionManager struct {
 	notif                  notifications.PubSub
 
 	// Sessions
-	sessLk   sync.RWMutex
+	sessLk   sync.Mutex
 	sessions map[uint64]Session
 
 	// Session Index
@@ -159,13 +159,13 @@ func (sm *SessionManager) ReceiveFrom(ctx context.Context, p peer.ID, blks []cid
 
 	// Notify each session that is interested in the blocks / HAVEs / DONT_HAVEs
 	for _, id := range sm.sessionInterestManager.InterestedSessions(blks, haves, dontHaves) {
-		sm.sessLk.RLock()
+		sm.sessLk.Lock()
 		if sm.sessions == nil { // check if SessionManager was shutdown
-			sm.sessLk.RUnlock()
+			sm.sessLk.Unlock()
 			return
 		}
 		sess, ok := sm.sessions[id]
-		sm.sessLk.RUnlock()
+		sm.sessLk.Unlock()
 
 		if ok {
 			sess.ReceiveFrom(p, blks, haves, dontHaves)