linux-kernel - [PATCH 1/3] platform/x86: wmi: Remove wmi_block

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Message-Id: <20241026193803.8802-1-W_Armin@gmx.de>
Date: Sat, 26 Oct 2024 21:38:01 +0200
From: Armin Wolf <W_Armin@....de>
To: hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com,
	corbet@....net
Cc: platform-driver-x86@...r.kernel.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] platform/x86: wmi: Remove wmi_block_list

The wmi_block_list is only used by guid_count() and without proper
protection. It also duplicates some of the WMI bus functionality.

Remove the wmi_block_list and use bus_for_each_dev() instead.

Signed-off-by: Armin Wolf <W_Armin@....de>
---
 drivers/platform/x86/wmi.c | 50 +++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 2d6885c67ac0..4704e79197f6 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -22,7 +22,6 @@
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/rwsem.h>
@@ -37,8 +36,6 @@ MODULE_AUTHOR("Carlos Corbacho");
 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
 MODULE_LICENSE("GPL");

-static LIST_HEAD(wmi_block_list);
-
 struct guid_block {
 	guid_t guid;
 	union {
@@ -63,7 +60,6 @@ enum {	/* wmi_block flags */

 struct wmi_block {
 	struct wmi_device dev;
-	struct list_head list;
 	struct guid_block gblock;
 	struct acpi_device *acpi_device;
 	struct rw_semaphore notify_lock;	/* Protects notify callback add/remove */
@@ -73,6 +69,10 @@ struct wmi_block {
 	unsigned long flags;
 };

+struct wmi_guid_count_context {
+	const guid_t *guid;
+	int count;
+};

 /*
  * If the GUID data block is marked as expensive, we must enable and
@@ -942,21 +942,30 @@ static const struct device_type wmi_type_data = {
 	.release = wmi_dev_release,
 };

-/*
- * _WDG is a static list that is only parsed at startup,
- * so it's safe to count entries without extra protection.
- */
+static int wmi_count_guids(struct device *dev, void *data)
+{
+	struct wmi_guid_count_context *context = data;
+	struct wmi_block *wblock = dev_to_wblock(dev);
+
+	if (guid_equal(&wblock->gblock.guid, context->guid))
+		context->count++;
+
+	return 0;
+}
+
 static int guid_count(const guid_t *guid)
 {
-	struct wmi_block *wblock;
-	int count = 0;
+	struct wmi_guid_count_context context = {
+		.guid = guid,
+		.count = 0,
+	};
+	int ret;

-	list_for_each_entry(wblock, &wmi_block_list, list) {
-		if (guid_equal(&wblock->gblock.guid, guid))
-			count++;
-	}
+	ret = bus_for_each_dev(&wmi_bus_type, NULL, &context, wmi_count_guids);
+	if (ret < 0)
+		return ret;

-	return count;
+	return context.count;
 }

 static int wmi_create_device(struct device *wmi_bus_dev,
@@ -967,7 +976,7 @@ static int wmi_create_device(struct device *wmi_bus_dev,
 	struct acpi_device_info *info;
 	acpi_handle method_handle;
 	acpi_status status;
-	uint count;
+	int count;

 	if (wblock->gblock.flags & ACPI_WMI_EVENT) {
 		wblock->dev.dev.type = &wmi_type_event;
@@ -1035,6 +1044,9 @@ static int wmi_create_device(struct device *wmi_bus_dev,
 	wblock->dev.dev.parent = wmi_bus_dev;

 	count = guid_count(&wblock->gblock.guid);
+	if (count < 0)
+		return count;
+
 	if (count) {
 		dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, count);
 		set_bit(WMI_GUID_DUPLICATED, &wblock->flags);
@@ -1120,14 +1132,11 @@ static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
 			continue;
 		}

-		list_add_tail(&wblock->list, &wmi_block_list);
-
 		retval = wmi_add_device(pdev, &wblock->dev);
 		if (retval) {
 			dev_err(wmi_bus_dev, "failed to register %pUL\n",
 				&wblock->gblock.guid);

-			list_del(&wblock->list);
 			put_device(&wblock->dev.dev);
 		}
 	}
@@ -1227,9 +1236,6 @@ static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, void *context

 static int wmi_remove_device(struct device *dev, void *data)
 {
-	struct wmi_block *wblock = dev_to_wblock(dev);
-
-	list_del(&wblock->list);
 	device_unregister(dev);

 	return 0;
--
2.39.5