Staging: hv: vmbus: Don't wait indefinitely for IRQ resouces

If an attempt is made to load the vmbus driver on a non-Hyper-V platform,
the load operation will hang since we currently wait indefinitely to
retrieve the IRQ information. This is done in the context of an acpi callback
context (which will obviously not happen when this driver is
loaded on a non-Hyper-V platform). This patch fixes the problem.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/vmbus_drv.c

@@ -768,7 +768,7 @@ MODULE_DEVICE_TABLE(pci, microsoft_hv_pci_table);
 
 static int __init hv_acpi_init(void)
 {
-	int ret;
+	int ret, t;
 
 	init_completion(&probe_event);
 
@@ -781,16 +781,25 @@ static int __init hv_acpi_init(void)
 	if (ret)
 		return ret;
 
-	wait_for_completion(&probe_event);
+	t = wait_for_completion_timeout(&probe_event, 5*HZ);
+	if (t == 0) {
+		ret = -ETIMEDOUT;
+		goto cleanup;
+	}
 
 	if (irq <= 0) {
-		acpi_bus_unregister_driver(&vmbus_acpi_driver);
-		return -ENODEV;
+		ret = -ENODEV;
+		goto cleanup;
 	}
 
 	ret = vmbus_bus_init(irq);
 	if (ret)
-		acpi_bus_unregister_driver(&vmbus_acpi_driver);
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	acpi_bus_unregister_driver(&vmbus_acpi_driver);
 	return ret;
 }