From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Mon, 27 Oct 2025 12:09:15 +0000 (+0100)
Subject: drm/client: Deprecate struct drm_client_buffer.gem
X-Git-Tag: v6.19-rc1~157^2~16^2~61
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ea39f2e66e61035e203530977a3df428345d03e2;p=thirdparty%2Fkernel%2Flinux.git

drm/client: Deprecate struct drm_client_buffer.gem

The client buffer's framebuffer holds a reference and pointer on
each of its GEM buffer objects. Thus the field gem in the client-
buffer struct is not necessary. Deprecated the field and convert
the client-buffer helpers to use the framebuffer's objects.

In drm_client_buffer_delete(), do a possible vunmap before releasing
the framebuffer. Otherwise we'd eventually release the framebuffer
before unmaping its buffer objects.

v2:
- avoid dependency on CONFIG_DRM_KMS_HELPER

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Tested-by: Francesco Valla <francesco@valla.it>
Link: https://patch.msgid.link/20251027121042.143588-5-tzimmermann@suse.de
---

diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
index c4db4fc7ba699..0aa56c4b912b0 100644
--- a/drivers/gpu/drm/drm_client.c
+++ b/drivers/gpu/drm/drm_client.c
@@ -17,6 +17,7 @@
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_mode.h>
 #include <drm/drm_print.h>
 
@@ -178,17 +179,17 @@ EXPORT_SYMBOL(drm_client_release);
 
 static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
 {
+	struct drm_gem_object *gem = buffer->fb->obj[0];
 	int ret;
 
+	drm_gem_vunmap(gem, &buffer->map);
+
 	ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file);
 	if (ret)
 		drm_err(buffer->client->dev,
 			"Error removing FB:%u (%d)\n", buffer->fb->base.id, ret);
 
-	if (buffer->gem) {
-		drm_gem_vunmap(buffer->gem, &buffer->map);
-		drm_gem_object_put(buffer->gem);
-	}
+	drm_gem_object_put(buffer->gem);
 
 	kfree(buffer);
 }
@@ -278,7 +279,7 @@ err_delete:
 int drm_client_buffer_vmap_local(struct drm_client_buffer *buffer,
 				 struct iosys_map *map_copy)
 {
-	struct drm_gem_object *gem = buffer->gem;
+	struct drm_gem_object *gem = buffer->fb->obj[0];
 	struct iosys_map *map = &buffer->map;
 	int ret;
 
@@ -307,7 +308,7 @@ EXPORT_SYMBOL(drm_client_buffer_vmap_local);
  */
 void drm_client_buffer_vunmap_local(struct drm_client_buffer *buffer)
 {
-	struct drm_gem_object *gem = buffer->gem;
+	struct drm_gem_object *gem = buffer->fb->obj[0];
 	struct iosys_map *map = &buffer->map;
 
 	drm_gem_vunmap_locked(gem, map);
@@ -338,9 +339,10 @@ EXPORT_SYMBOL(drm_client_buffer_vunmap_local);
 int drm_client_buffer_vmap(struct drm_client_buffer *buffer,
 			   struct iosys_map *map_copy)
 {
+	struct drm_gem_object *gem = buffer->fb->obj[0];
 	int ret;
 
-	ret = drm_gem_vmap(buffer->gem, &buffer->map);
+	ret = drm_gem_vmap(gem, &buffer->map);
 	if (ret)
 		return ret;
 	*map_copy = buffer->map;
@@ -359,7 +361,9 @@ EXPORT_SYMBOL(drm_client_buffer_vmap);
  */
 void drm_client_buffer_vunmap(struct drm_client_buffer *buffer)
 {
-	drm_gem_vunmap(buffer->gem, &buffer->map);
+	struct drm_gem_object *gem = buffer->fb->obj[0];
+
+	drm_gem_vunmap(gem, &buffer->map);
 }
 EXPORT_SYMBOL(drm_client_buffer_vunmap);
 
diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
index c674464f7e746..b01fc2a21f099 100644
--- a/include/drm/drm_client.h
+++ b/include/drm/drm_client.h
@@ -176,12 +176,9 @@ struct drm_client_buffer {
 	/**
 	 * @gem: GEM object backing this buffer
 	 *
-	 * FIXME: The dependency on GEM here isn't required, we could
-	 * convert the driver handle to a dma-buf instead and use the
-	 * backend-agnostic dma-buf vmap support instead. This would
-	 * require that the handle2fd prime ioctl is reworked to pull the
-	 * fd_install step out of the driver backend hooks, to make that
-	 * final step optional for internal users.
+	 * FIXME: The DRM framebuffer holds a reference on its GEM
+	 * buffer objects. Do not use this field in new code and
+	 * update existing users.
 	 */
 	struct drm_gem_object *gem;