[PATCH] fix PCI bridge swizzle on takara and eiger

This fixes NULL pointer dereference (bus->self) for PCI devices
on the root bus.

Ivan.

arch/alpha/kernel/sys_eiger.c

@@ -194,13 +194,8 @@ eiger_swizzle(struct pci_dev *dev, u8 *pinp)
 	   case 0x0f: bridge_count = 4; break; /* 4 */
 	};
 
-	/*  Check first for the built-in bridges on hose 0. */
-	if (hose->index == 0
-	    && PCI_SLOT(dev->bus->self->devfn) > 20-bridge_count) {
 	slot = PCI_SLOT(dev->devfn);
-	} else {
-		/* Must be a card-based bridge.  */
-		do {
+	while (dev->bus->self) {
 		/* Check for built-in bridges on hose 0. */
 		if (hose->index == 0
 		    && (PCI_SLOT(dev->bus->self->devfn)
@@ -208,13 +203,11 @@ eiger_swizzle(struct pci_dev *dev, u8 *pinp)
 			slot = PCI_SLOT(dev->devfn);
 			break;
 		}
+		/* Must be a card-based bridge.  */
 		pin = bridge_swizzle(pin, PCI_SLOT(dev->devfn));
 
 		/* Move up the chain of bridges.  */
 		dev = dev->bus->self;
-			/* Slot of the next bridge.  */
-			slot = PCI_SLOT(dev->devfn);
-		} while (dev->bus->self);
 	}
 	*pinp = pin;
 	return slot;

arch/alpha/kernel/sys_takara.c

@@ -231,8 +231,12 @@ takara_swizzle(struct pci_dev *dev, u8 *pinp)
 	int slot = PCI_SLOT(dev->devfn);
 	int pin = *pinp;
 	unsigned int ctlreg = inl(0x500);
-	unsigned int busslot = PCI_SLOT(dev->bus->self->devfn);
+	unsigned int busslot;
+
+	if (!dev->bus->self)
+		return slot;
 
+	busslot = PCI_SLOT(dev->bus->self->devfn);
 	/* Check for built-in bridges.  */
 	if (dev->bus->number != 0
 	    && busslot > 16