dm: add uevent to core

This patch adds a uevent skeleton to device-mapper.

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-uevent.c b/drivers/md/dm-uevent.c
new file mode 100644
index 0000000..53200c9
--- /dev/null
+++ b/drivers/md/dm-uevent.c
@@ -0,0 +1,72 @@
+/*
+ * Device Mapper Uevent Support (dm-uevent)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2007
+ * 	Author: Mike Anderson <andmike@linux.vnet.ibm.com>
+ */
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/kobject.h>
+
+#include "dm.h"
+#include "dm-uevent.h"
+
+#define DM_MSG_PREFIX "uevent"
+
+static struct kmem_cache *_dm_event_cache;
+
+struct dm_uevent {
+	struct mapped_device *md;
+	enum kobject_action action;
+	struct kobj_uevent_env ku_env;
+	struct list_head elist;
+};
+
+static void dm_uevent_free(struct dm_uevent *event)
+{
+	kmem_cache_free(_dm_event_cache, event);
+}
+
+static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md)
+{
+	struct dm_uevent *event;
+
+	event = kmem_cache_zalloc(_dm_event_cache, GFP_ATOMIC);
+	if (!event)
+		return NULL;
+
+	INIT_LIST_HEAD(&event->elist);
+	event->md = md;
+
+	return event;
+}
+
+int dm_uevent_init(void)
+{
+	_dm_event_cache = KMEM_CACHE(dm_uevent, 0);
+	if (!_dm_event_cache)
+		return -ENOMEM;
+
+	DMINFO("version 1.0.3");
+
+	return 0;
+}
+
+void dm_uevent_exit(void)
+{
+	kmem_cache_destroy(_dm_event_cache);
+}