From ec8ece9878ac8ab0db8e7f46d0a1030734024979 Mon Sep 17 00:00:00 2001
From: Tobie Morgan Hitchcock <tobie@abcum.com>
Date: Sat, 28 Apr 2018 22:08:19 +0100
Subject: [PATCH] Remove for loop from mutex

---
 db/mutex.go | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/db/mutex.go b/db/mutex.go
index 25894cb3..a1847c4e 100644
--- a/db/mutex.go
+++ b/db/mutex.go
@@ -35,23 +35,31 @@ func (m *mutex) Lock(ctx context.Context, key fmt.Stringer) {
 
 	_, v := m.item(ctx, key)
 
-	for {
-		select {
-		default:
-			if atomic.LoadUint32(&v.v) < vers(ctx) {
-				close(v.q)
-				panic(errRaceCondition)
-			}
-		case <-ctx.Done():
-			return
-		case <-v.q:
-			return
-		case v.l <- struct{}{}:
-			atomic.StoreUint32(&v.v, vers(ctx))
-			return
+	select {
+	case <-ctx.Done():
+		return
+	case <-v.q:
+		return
+	case v.l <- struct{}{}:
+		atomic.StoreUint32(&v.v, vers(ctx))
+		return
+	default:
+		if atomic.LoadUint32(&v.v) < vers(ctx) {
+			close(v.q)
+			panic(errRaceCondition)
 		}
 	}
 
+	select {
+	case <-ctx.Done():
+		return
+	case <-v.q:
+		return
+	case v.l <- struct{}{}:
+		atomic.StoreUint32(&v.v, vers(ctx))
+		return
+	}
+
 }
 
 func (m *mutex) Unlock(ctx context.Context, key fmt.Stringer) {