[PATCH] ppbus/ppc locking

[Bruce M. Simpson]

Here's a diff with my edits.

With these changes, the printer keeps being reported as busy, although I 
seem to be able to write to the /dev/lpt0 device, and it is seen.

As Ed Schouten pointed out on IRC probably this unit2minor stuff needs 
to go back in.

Back to work for this machine...

-------------- next part --------------
--- lpt.c.jhb	2009-01-23 14:31:43.000000000 +0000
+++ lpt.c	2009-01-23 15:21:08.000000000 +0000
@@ -140,6 +140,7 @@
 
 static timeout_t lptout;
 static int	lpt_port_test(device_t dev, u_char data, u_char mask);
+static int	lpt_detach(device_t dev);
 static int	lpt_detect(device_t dev);
 
 #define	DEVTOSOFTC(dev) \
@@ -408,12 +409,22 @@
 	sc->sc_inbuf = malloc(BUFSIZE, M_DEVBUF, M_WAITOK);
 	sc->sc_statbuf = malloc(BUFSTATSIZE, M_DEVBUF, M_WAITOK);
 	sc->sc_dev = dev;
-	sc->sc_cdev = make_dev(&lpt_cdevsw, unit,
+	sc->sc_cdev = make_dev(&lpt_cdevsw, unit * 2,
 	    UID_ROOT, GID_WHEEL, 0600, LPT_NAME "%d", unit);
+	if (sc->sc_cdev == NULL) {
+		device_printf(dev, "Unable to create data device node\n");
+		(void)lpt_detach(dev);
+		return (ENXIO);
+	}
 	sc->sc_cdev->si_drv1 = sc;
 	sc->sc_cdev->si_drv2 = 0;
-	sc->sc_cdev_bypass = make_dev(&lpt_cdevsw, unit,
+	sc->sc_cdev_bypass = make_dev(&lpt_cdevsw, (unit * 2) + 1,
 	    UID_ROOT, GID_WHEEL, 0600, LPT_NAME "%d.ctl", unit);
+	if (sc->sc_cdev_bypass == NULL) {
+		device_printf(dev, "Unable to create control device node\n");
+		(void)lpt_detach(dev);
+		return (ENXIO);
+	}
 	sc->sc_cdev_bypass->si_drv1 = sc;
 	sc->sc_cdev_bypass->si_drv2 = (void *)LP_BYPASS;
 	return (0);
@@ -425,8 +436,10 @@
 	struct lpt_data *sc = DEVTOSOFTC(dev);
 	device_t ppbus = device_get_parent(dev);
 
-	destroy_dev(sc->sc_cdev);
-	destroy_dev(sc->sc_cdev_bypass);
+	if (sc->sc_cdev)
+		destroy_dev(sc->sc_cdev);
+	if (sc->sc_cdev_bypass)
+		destroy_dev(sc->sc_cdev_bypass);
 	ppb_lock(ppbus);
 	lpt_release_ppbus(dev);
 	ppb_unlock(ppbus);