review feedback; improve docs

Signed-off-by: Vicent Marti <[email protected]>

go/pools/smartconnpool/pool.go

@@ -200,7 +200,7 @@ func (pool *ConnPool[C]) open() {
 
 	// The expire worker takes care of removing from the waiter list any clients whose
 	// context has been cancelled.
-	pool.runWorker(pool.close, 100*time.Millisecond, func(now time.Time) bool {
+	pool.runWorker(pool.close, 100*time.Millisecond, func(_ time.Time) bool {
 		maybeStarving := pool.wait.expire(false)
 
 		// Do not allow connections to starve; if there's waiters in the queue

go/pools/smartconnpool/stack.go

@@ -25,6 +25,9 @@ import (
 // connStack is a lock-free stack for Connection objects. It is safe to
 // use from several goroutines.
 type connStack[C Connection] struct {
+	// top is a pointer to the top node on the stack and to an increasing
+	// counter of pop operations, to prevent A-B-A races.
+	// See: https://en.wikipedia.org/wiki/ABA_problem
 	top atomic2.PointerAndUint64[Pooled[C]]
 }
 
@@ -58,25 +61,3 @@ func (s *connStack[C]) Peek() *Pooled[C] {
 	top, _ := s.top.Load()
 	return top
 }
-
-func (s *connStack[C]) PopAll(out []*Pooled[C]) []*Pooled[C] {
-	var oldHead *Pooled[C]
-
-	for {
-		var popCount uint64
-		oldHead, popCount = s.top.Load()
-		if oldHead == nil {
-			return out
-		}
-		if s.top.CompareAndSwap(oldHead, popCount, nil, popCount+1) {
-			break
-		}
-		runtime.Gosched()
-	}
-
-	for oldHead != nil {
-		out = append(out, oldHead)
-		oldHead = oldHead.next.Load()
-	}
-	return out
-}