platform/x86: wmi: Pass event data directly to legacy notify handlers

The current legacy WMI handlers are susceptible to picking up wrong
WMI event data on systems where different WMI devices share some
notification IDs.

Prevent this by letting the WMI driver core taking care of retrieving
the event data. This also simplifies the legacy WMI handlers and their
implementation inside the WMI driver core.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20240901031055.3030-3-W_Armin@gmx.de
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 18 insertions, 25 deletions

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 1d0b2d6040d1..6ab181dd94ab 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1227,40 +1227,33 @@ static int wmi_notify_device(struct device *dev, void *data)
 	if (!(wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *event))
 		return 0;
 
+	/* The ACPI WMI specification says that _WED should be
+	 * evaluated every time an notification is received, even
+	 * if no consumers are present.
+	 *
+	 * Some firmware implementations actually depend on this
+	 * by using a queue for events which will fill up if the
+	 * WMI driver core stops evaluating _WED due to missing
+	 * WMI event consumers.
+	 */
+	ret = wmi_get_notify_data(wblock, &obj);
+	if (ret < 0)
+		return -EIO;
+
 	down_read(&wblock->notify_lock);
 	/* The WMI driver notify handler conflicts with the legacy WMI handler.
 	 * Because of this the WMI driver notify handler takes precedence.
 	 */
 	if (wblock->dev.dev.driver && wblock->driver_ready) {
-		ret = wmi_get_notify_data(wblock, &obj);
-		if (ret >= 0) {
-			wmi_notify_driver(wblock, obj);
-			kfree(obj);
-		}
+		wmi_notify_driver(wblock, obj);
 	} else {
-		if (wblock->handler) {
-			wblock->handler(*event, wblock->handler_data);
-		} else {
-			/* The ACPI WMI specification says that _WED should be
-			 * evaluated every time an notification is received, even
-			 * if no consumers are present.
-			 *
-			 * Some firmware implementations actually depend on this
-			 * by using a queue for events which will fill up if the
-			 * WMI driver core stops evaluating _WED due to missing
-			 * WMI event consumers.
-			 *
-			 * Because of this we need this seemingly useless call to
-			 * wmi_get_notify_data() which in turn evaluates _WED.
-			 */
-			ret = wmi_get_notify_data(wblock, &obj);
-			if (ret >= 0)
-				kfree(obj);
-		}
-
+		if (wblock->handler)
+			wblock->handler(obj, wblock->handler_data);
 	}
 	up_read(&wblock->notify_lock);
 
+	kfree(obj);
+
 	acpi_bus_generate_netlink_event("wmi", acpi_dev_name(wblock->acpi_device), *event, 0);
 
 	return -EBUSY;