PCI: acpiphp: check whether _ADR evaluation succeeded

commit dfb117b3 upstream.

Check whether we evaluated _ADR successfully.  Previously we ignored
failure, so we would have used garbage data from the stack as the device
and function number.

We return AE_OK so that we ignore only this slot and continue looking
for other slots.

Found by Coverity (CID 113981).
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[bwh: Backported to 2.6.32/3.0: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pci/hotplug/acpiphp_glue.c

@@ -131,7 +131,12 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
 	if (!acpi_pci_check_ejectable(pbus, handle) && !is_dock_device(handle))
 		return AE_OK;
 
-	acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
+	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
+	if (ACPI_FAILURE(status)) {
+		warn("can't evaluate _ADR (%#x)\n", status);
+		return AE_OK;
+	}
+
 	device = (adr >> 16) & 0xffff;
 	function = adr & 0xffff;