udlfb: fix some inconsistent NULL checking

In the current kernel, then kzalloc() can't fail for small allocations,
but if it did fail then we would have a NULL dereference in the error
handling.  Also in dlfb_usb_disconnect() if "info" were NULL then it
would cause an Oops inside the unregister_framebuffer() function but it
can't be NULL so let's remove that check.

Fixes: 68a958a ("udlfb: handle unplug properly")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Wen Yang <wen.yang99@zte.com.cn>
[b.zolnierkie: added "Fixes:" tag]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/udlfb.c

@@ -1598,7 +1598,7 @@ static int dlfb_usb_probe(struct usb_interface *intf,
 	dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
 	if (!dlfb) {
 		dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
-		goto error;
+		return -ENOMEM;
 	}
 
 	INIT_LIST_HEAD(&dlfb->deferred_free);
@@ -1703,7 +1703,7 @@ static int dlfb_usb_probe(struct usb_interface *intf,
 error:
 	if (dlfb->info) {
 		dlfb_ops_destroy(dlfb->info);
-	} else if (dlfb) {
+	} else {
 		usb_put_dev(dlfb->udev);
 		kfree(dlfb);
 	}
@@ -1730,12 +1730,10 @@ static void dlfb_usb_disconnect(struct usb_interface *intf)
 	/* this function will wait for all in-flight urbs to complete */
 	dlfb_free_urb_list(dlfb);
 
-	if (info) {
-		/* remove udlfb's sysfs interfaces */
-		for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
-			device_remove_file(info->dev, &fb_device_attrs[i]);
-		device_remove_bin_file(info->dev, &edid_attr);
-	}
+	/* remove udlfb's sysfs interfaces */
+	for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
+		device_remove_file(info->dev, &fb_device_attrs[i]);
+	device_remove_bin_file(info->dev, &edid_attr);
 
 	unregister_framebuffer(info);
 }