use a single channel for all validation results

floodsub.go

@@ -394,7 +394,8 @@ func (p *PubSub) validate(subs []*Subscription, src peer.ID, msg *Message) {
 	ctx, cancel := context.WithCancel(p.ctx)
 	defer cancel()
 
-	results := make([]chan bool, 0, len(subs))
+	rch := make(chan bool, len(subs))
+	rcount := 0
 	throttle := false
 
 loop:
@@ -403,15 +404,14 @@ loop:
 			continue
 		}
 
-		rch := make(chan bool, 1)
-		results = append(results, rch)
+		rcount++
 
 		select {
 		case sub.validateThrottle <- struct{}{}:
-			go func(sub *Subscription, rch chan bool) {
+			go func(sub *Subscription) {
 				rch <- sub.validateMsg(ctx, msg)
 				<-sub.validateThrottle
-			}(sub, rch)
+			}(sub)
 
 		default:
 			log.Debugf("validation throttled for topic %s", sub.topic)
@@ -425,7 +425,7 @@ loop:
 		return
 	}
 
-	for _, rch := range results {
+	for i := 0; i < rcount; i++ {
 		valid := <-rch
 		if !valid {
 			log.Warningf("message validation failed; dropping message from %s", src)