gp.m.locksHeldLen--
				break
			}
		}
		if !found {
			println(gp.m.procid, ":", l.rank.String(), l.rank, l)
			throw("unlock without matching lock acquire")
		}
		unlock2(l)
	})
}

// releaseLockRankAndM releases a rank which is not associated with a mutex
// lock. To maintain the invariant that an M with m.locks==0 does not hold any

func (m *rwmutexWrite) Unlock1() { m.mu.Unlock() }
func (m *rwmutexWrite) Lock2()   { m.mu.Lock() }
func (m *rwmutexWrite) Unlock2() { m.mu.Unlock() }

type rwmutexReadWrite struct {
	mu sync.RWMutex
}

func (m *rwmutexReadWrite) Lock1()   { m.mu.RLock() }
func (m *rwmutexReadWrite) Unlock1() { m.mu.RUnlock() }
func (m *rwmutexReadWrite) Lock2()   { m.mu.Lock() }
func (m *rwmutexReadWrite) Unlock2() { m.mu.Unlock() }

	// to indicate we haven't sufficiently unlocked lockers to avoid deadlocks.
	//
	// Caller may use this as an indication to call again.
	return !checkFailedUnlocks(*locks, tolerance)
}

// Unlock unlocks the write lock.
//
// It is a run-time error if dm is not locked on entry to Unlock.
func (dm *DRWMutex) Unlock(ctx context.Context) {
	dm.m.Lock()
	dm.cancelRefresh()
	dm.m.Unlock()

	gp.parkingOnChan.Store(false)
	// Make sure we unlock after setting activeStackChans and
	// unsetting parkingOnChan. The moment we unlock chanLock
	// we risk gp getting readied by a channel operation and
	// so gp could continue running before everything before
	// the unlock is visible (even to gp itself).
	unlock((*mutex)(chanLock))
	return true
}

// compiler implements
//

	sys.aMutex.Lock()
	defer sys.aMutex.Unlock()
	if v, ok := sys.arnErrsMap[arn]; !ok {
		sys.arnErrsMap[arn] = arnErrs{
			updateInProgress: true,
			count:            v.count + 1,
			bucket:           bucket,
		}
	}
}

func (sys *BucketTargetSys) markRefreshDone(bucket, arn string) {
	sys.aMutex.Lock()
	defer sys.aMutex.Unlock()
	if v, ok := sys.arnErrsMap[arn]; ok {

		globalHTTPStats.incS3RequestsIncoming()

		if r.Header.Get(globalObjectPerfUserMetadata) == "" {
			if val := globalServiceFreeze.Load(); val != nil {
				if unlock, ok := val.(chan struct{}); ok && unlock != nil {
					// Wait until unfrozen.
					select {
					case <-unlock:
					case <-r.Context().Done():
						// if client canceled we don't need to wait here forever.
						return
					}
				}
			}
		}

	defer h.mu.RUnlock()

	return h.Object
}

func (h *healingTracker) setObject(object string) {
	h.mu.Lock()
	defer h.mu.Unlock()

	h.Object = object
}

func (h *healingTracker) updateProgress(success, skipped bool, bytes uint64) {
	h.mu.Lock()
	defer h.mu.Unlock()

	switch {
	case success:
		h.ItemsHealed++
		h.BytesDone += bytes
	case skipped:
		h.ItemsSkipped++

			select {
			// Check after a second
			case <-time.After(time.Second):
				h.mutex.Unlock()
				continue

			case <-h.ctx.Done():
				h.mutex.Unlock()
				// discard result and return.
				return errHealStopSignalled

			// Timeout if no results consumed for too long.
			case <-unconsumedTimer.C:
				h.mutex.Unlock()
				return errHealIdleTimeout
			}
		}
		break
	}

	if stats == nil {
		return
	}
	stats.Lock()
	defer stats.Unlock()
	if stats.apiStats == nil {
		stats.apiStats = make(map[string]int)
	}
	stats.apiStats[api]++
}

// Dec increments the api stats counter.
func (stats *HTTPAPIStats) Dec(api string) {
	if stats == nil {
		return
	}
	stats.Lock()
	defer stats.Unlock()
	if val, ok := stats.apiStats[api]; ok && val > 0 {
		stats.apiStats[api]--

func (t *timer) lock() {
	lock(&t.mu)
	t.trace("lock")
}

// unlock updates t.astate and unlocks the timer.
func (t *timer) unlock() {
	t.trace("unlock")
	// Let heap fast paths know whether heap[i].when is accurate.
	// Also let maybeRunChan know whether channel is in heap.
	t.astate.Store(t.state)
	unlock(&t.mu)
}

// hchan returns the channel in t.arg.
// t must be a timer with a channel.