PERFORCE change 146544 for review

[Ed Schouten]

http://perforce.freebsd.org/chv.cgi?CH=146544

Change 146544 by ed at ed_flippo on 2008/08/03 17:36:53

	Add a counter to store the number of null modem devices.

Affected files ...

.. //depot/projects/mpsafetty/sys/dev/nmdm/nmdm.c#4 edit

Differences ...

==== //depot/projects/mpsafetty/sys/dev/nmdm/nmdm.c#4 (text+ko) ====

@@ -93,12 +93,16 @@
 	struct mtx	ns_mtx;
 };
 
+static int nmdm_count = 0;
+
 static struct nmdmsoftc *
 nmdm_alloc(unsigned long unit, struct ucred *cr)
 {
 	struct nmdmsoftc *ns;
 	struct tty *tp;
 
+	atomic_add_acq_int(&nmdm_count, 1);
+
 	ns = malloc(sizeof(*ns), M_NMDM, M_WAITOK|M_ZERO);
 	mtx_init(&ns->ns_mtx, "nmdm", NULL, MTX_DEF);
 
@@ -344,8 +348,9 @@
 		break;
 
 	case MOD_UNLOAD:
+		if (nmdm_count != 0)
+			return (EBUSY);
 		EVENTHANDLER_DEREGISTER(dev_clone, tag);
-		/* XXX: track counter! */
 		break;
 
 	default: