From f97e058cfe8032504e310bd5c20e35d640ef2858 Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello@dell.com>
Date: Wed, 1 Nov 2017 14:25:28 -0500
Subject: [PATCH] platform/x86: wmi: Don't allow drivers to get each other's GUIDs
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Git-commit: f97e058cfe8032504e310bd5c20e35d640ef2858
Patch-mainline: v4.15-rc1
References: FATE#325842

The only driver using this was dell-wmi, and it really was a hack.
The driver was getting a data attribute from another driver and this
type of action should not be encouraged.

Rather drivers that need to interact with one another should pass
data back and forth via exported functions.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Reviewed-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/platform/x86/wmi.c |   17 -----------------
 include/linux/wmi.h        |    4 ----
 2 files changed, 21 deletions(-)

--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -368,23 +368,6 @@ union acpi_object *wmidev_block_query(st
 }
 EXPORT_SYMBOL_GPL(wmidev_block_query);
 
-struct wmi_device *wmidev_get_other_guid(struct wmi_device *wdev,
-					 const char *guid_string)
-{
-	struct wmi_block *this_wb = container_of(wdev, struct wmi_block, dev);
-	struct wmi_block *other_wb;
-
-	if (!find_guid(guid_string, &other_wb))
-		return NULL;
-
-	if (other_wb->acpi_device != this_wb->acpi_device)
-		return NULL;
-
-	get_device(&other_wb->dev.dev);
-	return &other_wb->dev;
-}
-EXPORT_SYMBOL_GPL(wmidev_get_other_guid);
-
 /**
  * wmi_set_block - Write to a WMI block
  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
--- a/include/linux/wmi.h
+++ b/include/linux/wmi.h
@@ -36,10 +36,6 @@ extern acpi_status wmidev_evaluate_metho
 extern union acpi_object *wmidev_block_query(struct wmi_device *wdev,
 					     u8 instance);
 
-/* Gets another device on the same bus.  Caller must put_device the result. */
-extern struct wmi_device *wmidev_get_other_guid(struct wmi_device *wdev,
-						const char *guid_string);
-
 struct wmi_device_id {
 	const char *guid_string;
 };