drm/cma-helper: Make default object functions the default

As GEM object functions are now mandatory, DRM drivers based on CMA
helpers either set them in their implementation of gem_create_object,
or use the default via drm_gem_cma_create_object_default_funcs().

Simplify this by setting the default CMA object functions for all
objects that don't have any functions of their own. Follows the pattern
of similar code in SHMEM and VRAM helpers. The function
drm_gem_cma_create_object_default_funcs() is redundant and therefore
being removed.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201106131632.6796-1-tzimmermann@suse.de

drivers/gpu/drm/drm_gem_cma_helper.c

@@ -33,6 +33,14 @@
  * display drivers that are unable to map scattered buffers via an IOMMU.
  */
 
+static const struct drm_gem_object_funcs drm_gem_cma_default_funcs = {
+	.free = drm_gem_cma_free_object,
+	.print_info = drm_gem_cma_print_info,
+	.get_sg_table = drm_gem_cma_prime_get_sg_table,
+	.vmap = drm_gem_cma_prime_vmap,
+	.vm_ops = &drm_gem_cma_vm_ops,
+};
+
 /**
  * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
  * @drm: DRM device
@@ -58,6 +66,10 @@ __drm_gem_cma_create(struct drm_device *drm, size_t size)
 		gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
 	if (!gem_obj)
 		return ERR_PTR(-ENOMEM);
+
+	if (!gem_obj->funcs)
+		gem_obj->funcs = &drm_gem_cma_default_funcs;
+
 	cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base);
 
 	ret = drm_gem_object_init(drm, gem_obj, size);
@@ -541,41 +553,6 @@ int drm_gem_cma_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
 }
 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
 
-static const struct drm_gem_object_funcs drm_gem_cma_default_funcs = {
-	.free = drm_gem_cma_free_object,
-	.print_info = drm_gem_cma_print_info,
-	.get_sg_table = drm_gem_cma_prime_get_sg_table,
-	.vmap = drm_gem_cma_prime_vmap,
-	.vm_ops = &drm_gem_cma_vm_ops,
-};
-
-/**
- * drm_gem_cma_create_object_default_funcs - Create a CMA GEM object with a
- *                                           default function table
- * @dev: DRM device
- * @size: Size of the object to allocate
- *
- * This sets the GEM object functions to the default CMA helper functions.
- * This function can be used as the &drm_driver.gem_create_object callback.
- *
- * Returns:
- * A pointer to a allocated GEM object or an error pointer on failure.
- */
-struct drm_gem_object *
-drm_gem_cma_create_object_default_funcs(struct drm_device *dev, size_t size)
-{
-	struct drm_gem_cma_object *cma_obj;
-
-	cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
-	if (!cma_obj)
-		return NULL;
-
-	cma_obj->base.funcs = &drm_gem_cma_default_funcs;
-
-	return &cma_obj->base;
-}
-EXPORT_SYMBOL(drm_gem_cma_create_object_default_funcs);
-
 /**
  * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another driver's
  *	scatter/gather table and get the virtual address of the buffer

drivers/gpu/drm/pl111/pl111_drv.c

@@ -224,7 +224,6 @@ static const struct drm_driver pl111_drm_driver = {
 	.major = 1,
 	.minor = 0,
 	.patchlevel = 0,
-	.gem_create_object = drm_gem_cma_create_object_default_funcs,
 	.dumb_create = drm_gem_cma_dumb_create,
 	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,

include/drm/drm_gem_cma_helper.h

@@ -105,9 +105,6 @@ int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
 			   struct vm_area_struct *vma);
 int drm_gem_cma_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
 
-struct drm_gem_object *
-drm_gem_cma_create_object_default_funcs(struct drm_device *dev, size_t size);
-
 /**
  * DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE - CMA GEM driver operations
  * @dumb_create_func: callback function for .dumb_create
@@ -122,7 +119,6 @@ drm_gem_cma_create_object_default_funcs(struct drm_device *dev, size_t size);
  * DRM_GEM_CMA_DRIVER_OPS_VMAP_WITH_DUMB_CREATE() instead.
  */
 #define DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE(dumb_create_func) \
-	.gem_create_object	= drm_gem_cma_create_object_default_funcs, \
 	.dumb_create		= (dumb_create_func), \
 	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd, \
 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle, \
@@ -161,7 +157,6 @@ drm_gem_cma_create_object_default_funcs(struct drm_device *dev, size_t size);
  * DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE() instead.
  */
 #define DRM_GEM_CMA_DRIVER_OPS_VMAP_WITH_DUMB_CREATE(dumb_create_func) \
-	.gem_create_object	= drm_gem_cma_create_object_default_funcs, \
 	.dumb_create		= dumb_create_func, \
 	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd, \
 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle, \