[PATCH] Fix ide-disk.c oops caused by hwif == NULL

1. Move hwif_to_node to ide.h

2. Use hwif_to_node in ide-disk.c

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index f9c1acb4..c9d3a00 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -1220,7 +1220,7 @@
 		goto failed;
 
 	g = alloc_disk_node(1 << PARTN_BITS,
-			pcibus_to_node(drive->hwif->pci_dev->bus));
+			hwif_to_node(drive->hwif));
 	if (!g)
 		goto out_free_idkp;