device: use defer to simplify peer.NewTimer

This also makes the lifetime of modifyingLock more prominent.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

diff --git a/device/timers.go b/device/timers.go
index 0232eefc63119f2e240cfea79979e3354020ca63..48cef94b2269932f7b7b6487b2ec494da8674992 100644 (file)
--- a/device/timers.go
+++ b/device/timers.go
@@ -29,18 +29,17 @@ func (peer *Peer) NewTimer(expirationFunction func(*Peer)) *Timer {
        timer := &Timer{}
        timer.Timer = time.AfterFunc(time.Hour, func() {
                timer.runningLock.Lock()
+               defer timer.runningLock.Unlock()
 
                timer.modifyingLock.Lock()
                if !timer.isPending {
                        timer.modifyingLock.Unlock()
-                       timer.runningLock.Unlock()
                        return
                }
                timer.isPending = false
                timer.modifyingLock.Unlock()
 
                expirationFunction(peer)
-               timer.runningLock.Unlock()
        })
        timer.Stop()
        return timer