PERFORCE change 162793 for review

[Scott Long]

http://perforce.freebsd.org/chv.cgi?CH=162793

Change 162793 by scottl at scottl-y1 on 2009/05/26 17:38:49

	Start locking access to the devclasses global list.

Affected files ...

.. //depot/projects/scottl-camlock/src/sys/kern/subr_bus.c#20 edit

Differences ...

==== //depot/projects/scottl-camlock/src/sys/kern/subr_bus.c#20 (text+ko) ====

@@ -764,6 +764,8 @@
 
 static devclass_list_t devclasses = TAILQ_HEAD_INITIALIZER(devclasses);
 
+static struct mtx devclasses_mtx;
+MTX_SYSINIT(devclasses, &devclasses_mtx, "devclass global mtx", MTX_DEF);
 
 /**
  * @internal
@@ -781,11 +783,13 @@
  * @param create	non-zero to create a devclass
  */
 static devclass_t
-devclass_find_internal(const char *classname, const char *parentname,
-		       int create)
+devclass_find_internal_locked(const char *classname, const char *parentname,
+			      int create)
 {
 	devclass_t dc;
 
+	mtx_assert(&devclasses_mtx, MA_OWNED);
+
 	PDEBUG(("looking for %s", classname));
 	if (!classname)
 		return (NULL);
@@ -820,13 +824,26 @@
 	 */
 	if (parentname && dc && !dc->parent &&
 	    strcmp(classname, parentname) != 0) {
-		dc->parent = devclass_find_internal(parentname, NULL, TRUE);
+		dc->parent = devclass_find_internal_locked(parentname, NULL,
+							   TRUE);
 		dc->parent->flags |= DC_HAS_CHILDREN;
 	}
 
 	return (dc);
 }
 
+static devclass_t
+devclass_find_internal(const char *classname, const char *parentname,
+		       int create)
+{
+	devclass_t dc;
+
+	mtx_lock(&devclasses_mtx);
+	dc = devclass_find_internal_locked(classname, parentname, create);
+	mtx_unlock(&devclasses_mtx);
+	return (dc);
+}
+
 /**
  * @brief Create a device class
  *