Remove checkpoint_count from runsc wait --checkpoint

This is done because external callers are not able to know
the snapshot generation number from the outside.

PiperOrigin-RevId: 707979556

runsc/boot/controller.go

@@ -722,13 +722,11 @@ func (cm *containerManager) WaitPID(args *WaitPIDArgs, waitStatus *uint32) error
 	return err
 }
 
-// WaitCheckpoint waits for the Kernel to have been successfully checkpointed
-// n-1 times, then waits for either the n-th successful checkpoint (in which
-// case it returns nil) or any number of failed checkpoints (in which case it
-// returns an error returned by any such failure).
-func (cm *containerManager) WaitCheckpoint(n *uint32, _ *struct{}) error {
-	err := cm.l.k.WaitCheckpoint(*n)
-	log.Debugf("containerManager.WaitCheckpoint, n = %d, err = %v", *n, err)
+// WaitCheckpoint waits for the Kernel to have been successfully checkpointed.
+func (cm *containerManager) WaitCheckpoint(*struct{}, *struct{}) error {
+	log.Debugf("containerManager.WaitCheckpoint")
+	err := cm.l.k.WaitForCheckpoint()
+	log.Debugf("containerManager.WaitCheckpoint done, err = %v", err)
 	return err
 }
 

runsc/boot/restore.go

@@ -735,7 +735,8 @@ func (r *restorer) restore(l *Loader) error {
 		// Restore was successful, so increment the checkpoint count manually. The
 		// count was saved while the previous kernel was being saved and checkpoint
 		// success was unknown at that time. Now we know the checkpoint succeeded.
-		l.k.IncCheckpointCount()
+		l.k.OnRestoreDone()
+
 		log.Infof("Restore successful")
 	}()
 	return nil
@@ -746,7 +747,6 @@ func (l *Loader) save(o *control.SaveOpts) (err error) {
 		// This closure is required to capture the final value of err.
 		l.k.OnCheckpointAttempt(err)
 	}()
-	l.k.ResetCheckpointStatus()
 
 	// TODO(gvisor.dev/issues/6243): save/restore not supported w/ hostinet
 	if l.root.conf.Network == config.NetworkHost {