platform/x86: wmi: Decouple legacy WMI notify handlers from wmi_block_list

Until now, legacy WMI notify handler functions where using the
wmi_block_list, which did no refcounting on the returned WMI device.
This meant that the WMI device could disappear at any moment,
potentially leading to various errors.
Fix this by using bus_find_device() which returns an actual
reference to the found WMI device.

Tested on a Dell Inspiron 3505 and a Acer Aspire E1-731.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240103192707.115512-4-W_Armin@gmx.de
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 4e2d0e15b15593e48d0938f5c33a8b3870ffdb49..699157ce347ce10cff2a4a6c6f55457e5576207d 100644 (file)
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -219,6 +219,17 @@ static int wmidev_match_guid(struct device *dev, const void *data)
        return 0;
 }
 
+static int wmidev_match_notify_id(struct device *dev, const void *data)
+{
+       struct wmi_block *wblock = dev_to_wblock(dev);
+       const u32 *notify_id = data;
+
+       if (wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *notify_id)
+               return 1;
+
+       return 0;
+}
+
 static struct bus_type wmi_bus_type;
 
 static struct wmi_device *wmi_find_device_by_guid(const char *guid_string)
@@ -238,6 +249,17 @@ static struct wmi_device *wmi_find_device_by_guid(const char *guid_string)
        return dev_to_wdev(dev);
 }
 
+static struct wmi_device *wmi_find_event_by_notify_id(const u32 notify_id)
+{
+       struct device *dev;
+
+       dev = bus_find_device(&wmi_bus_type, NULL, &notify_id, wmidev_match_notify_id);
+       if (!dev)
+               return ERR_PTR(-ENODEV);
+
+       return to_wmi_device(dev);
+}
+
 static void wmi_device_put(struct wmi_device *wdev)
 {
        put_device(&wdev->dev);
@@ -572,34 +594,30 @@ acpi_status wmi_install_notify_handler(const char *guid,
                                       wmi_notify_handler handler,
                                       void *data)
 {
-       struct wmi_block *block;
-       guid_t guid_input;
-
-       if (!guid || !handler)
-               return AE_BAD_PARAMETER;
-
-       if (guid_parse(guid, &guid_input))
-               return AE_BAD_PARAMETER;
-
-       list_for_each_entry(block, &wmi_block_list, list) {
-               acpi_status wmi_status;
+       struct wmi_block *wblock;
+       struct wmi_device *wdev;
+       acpi_status status;
 
-               if (guid_equal(&block->gblock.guid, &guid_input)) {
-                       if (block->handler)
-                               return AE_ALREADY_ACQUIRED;
+       wdev = wmi_find_device_by_guid(guid);
+       if (IS_ERR(wdev))
+               return AE_ERROR;
 
-                       block->handler = handler;
-                       block->handler_data = data;
+       wblock = container_of(wdev, struct wmi_block, dev);
+       if (wblock->handler) {
+               status = AE_ALREADY_ACQUIRED;
+       } else {
+               wblock->handler = handler;
+               wblock->handler_data = data;
 
-                       wmi_status = wmi_method_enable(block, true);
-                       if (ACPI_FAILURE(wmi_status))
-                               dev_warn(&block->dev.dev, "Failed to enable device\n");
+               if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
+                       dev_warn(&wblock->dev.dev, "Failed to enable device\n");
 
-                       return AE_OK;
-               }
+               status = AE_OK;
        }
 
-       return AE_NOT_EXIST;
+       wmi_device_put(wdev);
+
+       return status;
 }
 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 
@@ -613,34 +631,30 @@ EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
  */
 acpi_status wmi_remove_notify_handler(const char *guid)
 {
-       struct wmi_block *block;
-       guid_t guid_input;
-
-       if (!guid)
-               return AE_BAD_PARAMETER;
-
-       if (guid_parse(guid, &guid_input))
-               return AE_BAD_PARAMETER;
-
-       list_for_each_entry(block, &wmi_block_list, list) {
-               acpi_status wmi_status;
+       struct wmi_block *wblock;
+       struct wmi_device *wdev;
+       acpi_status status;
 
-               if (guid_equal(&block->gblock.guid, &guid_input)) {
-                       if (!block->handler)
-                               return AE_NULL_ENTRY;
+       wdev = wmi_find_device_by_guid(guid);
+       if (IS_ERR(wdev))
+               return AE_ERROR;
 
-                       wmi_status = wmi_method_enable(block, false);
-                       if (ACPI_FAILURE(wmi_status))
-                               dev_warn(&block->dev.dev, "Failed to disable device\n");
+       wblock = container_of(wdev, struct wmi_block, dev);
+       if (!wblock->handler) {
+               status = AE_NULL_ENTRY;
+       } else {
+               if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
+                       dev_warn(&wblock->dev.dev, "Failed to disable device\n");
 
-                       block->handler = NULL;
-                       block->handler_data = NULL;
+               wblock->handler = NULL;
+               wblock->handler_data = NULL;
 
-                       return AE_OK;
-               }
+               status = AE_OK;
        }
 
-       return AE_NOT_EXIST;
+       wmi_device_put(wdev);
+
+       return status;
 }
 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 
@@ -657,15 +671,19 @@ EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
 {
        struct wmi_block *wblock;
+       struct wmi_device *wdev;
+       acpi_status status;
 
-       list_for_each_entry(wblock, &wmi_block_list, list) {
-               struct guid_block *gblock = &wblock->gblock;
+       wdev = wmi_find_event_by_notify_id(event);
+       if (IS_ERR(wdev))
+               return AE_NOT_FOUND;
 
-               if ((gblock->flags & ACPI_WMI_EVENT) && gblock->notify_id == event)
-                       return get_event_data(wblock, out);
-       }
+       wblock = container_of(wdev, struct wmi_block, dev);
+       status = get_event_data(wblock, out);
 
-       return AE_NOT_FOUND;
+       wmi_device_put(wdev);
+
+       return status;
 }
 EXPORT_SYMBOL_GPL(wmi_get_event_data);