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 c4db4fc7ba6991615e93e1126b9bc36fd3dbc38b..0aa56c4b912b0eef513aa67580d9b18fb67d559b 100644 (file)
--- 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 c674464f7e7466f06993d23a1f8b207a5a7f8016..b01fc2a21f0994a693c40d3f89a50127fc4bba3c 100644 (file)
--- 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;