Test for hwh->type not hwh.
--- diff/drivers/md/dm-mpath.c	2004-10-29 16:46:41.000000000 +0100
+++ source/drivers/md/dm-mpath.c	2004-10-29 16:46:22.000000000 +0100
@@ -195,7 +195,7 @@
 	m->current_pg = path->pg;
 
 	/* Must we initialise the PG first, and queue I/O till it's ready? */
-	if (hwh && hwh->type->pg_init) {
+	if (hwh->type && hwh->type->pg_init) {
 		m->pg_init_required = 1;
 		m->queue_io = 1;
 	} else {
@@ -808,7 +808,7 @@
 		}
 		spin_unlock(&m->lock);
 
-		if (hwh && hwh->type->err)
+		if (hwh->type && hwh->type->err)
 			err_flags = hwh->type->err(hwh, bio);
 
 		if (err_flags & MP_FAIL_PATH)
@@ -870,7 +870,7 @@
 	char buffer[32];
 	char state;
 
-	if (hwh && hwh->type->status)
+	if (hwh->type && hwh->type->status)
 		sz += hwh->type->status(hwh, type, result + sz, maxlen = sz);
 	else if (type == STATUSTYPE_INFO)
 		DMEMIT("0 ");