drm: Move legacy device list out of drm_driver

The drm_driver structure contains a single field (legacy_dev_list) that
is modified by the DRM core, used to store a linked list of legacy DRM
devices associated with the driver. In order to make the structure
const, move the field out to a global variable. This requires locking
access to the global where the local field didn't require serialization,
but this only affects legacy drivers, and isn't in any hot path.

While at it, compile-out the legacy_dev_list field when DRM_LEGACY isn't
defined.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index 283a93ce4617..bd5abe7cd48f 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -51,13 +51,6 @@ enum switch_power_state {
  * may contain multiple heads.
  */
 struct drm_device {
-	/**
-	 * @legacy_dev_list:
-	 *
-	 * List of devices per driver for stealth attach cleanup
-	 */
-	struct list_head legacy_dev_list;
-
 	/** @if_version: Highest interface version set */
 	int if_version;
 
@@ -336,6 +329,9 @@ struct drm_device {
 	/* Everything below here is for legacy driver, never use! */
 	/* private: */
 #if IS_ENABLED(CONFIG_DRM_LEGACY)
+	/* List of devices per driver for stealth attach cleanup */
+	struct list_head legacy_dev_list;
+
 	/* Context handle management - linked list of context handles */
 	struct list_head ctxlist;