Commit 89c815ef authored by Thomas Zimmermann's avatar Thomas Zimmermann Committed by Alex Deucher
Browse files

drm/ttm: Introduce ttm_bo_get() and ttm_bo_put() for ref counting 



The TTM buffer-object interface provides ttm_bo_reference() and
ttm_bo_unref() for managing reference counts. Replacing them with
ttm_bo_get() and ttm_bo_put() aligns the API with conventions used
throughout the Linux kernel.

The implementation of ttm_bo_unref() clears the supplied pointer
to NULL. This leads to workarounds where the caller saves the
pointer's value before de-referencing the BO. ttm_bo_put() does
not clear the supplied pointer.

Signed-off-by: default avatarThomas Zimmermann <contact@tzimmermann.org>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 31e1c597

drivers/gpu/drm/ttm/ttm_bo.c

+7 −1
Original line number Diff line number Diff line
@@ -587,12 +587,18 @@ static void ttm_bo_release(struct kref *kref) 
	kref_put(&bo->list_kref, ttm_bo_release_list);

}



void ttm_bo_put(struct ttm_buffer_object *bo)

{

	kref_put(&bo->kref, ttm_bo_release);

}

EXPORT_SYMBOL(ttm_bo_put);



void ttm_bo_unref(struct ttm_buffer_object **p_bo)

{

	struct ttm_buffer_object *bo = *p_bo;



	*p_bo = NULL;

	kref_put(&bo->kref, ttm_bo_release);

	ttm_bo_put(bo);

}

EXPORT_SYMBOL(ttm_bo_unref);

include/drm/ttm/ttm_bo_api.h

+24 −1
Original line number Diff line number Diff line
@@ -283,18 +283,30 @@ struct ttm_operation_ctx { 
/* when serving page fault or suspend, allow alloc anyway */

#define TTM_OPT_FLAG_FORCE_ALLOC		0x2



/**

 * ttm_bo_get - reference a struct ttm_buffer_object

 *

 * @bo: The buffer object.

 */

static inline void ttm_bo_get(struct ttm_buffer_object *bo)

{

	kref_get(&bo->kref);

}



/**

 * ttm_bo_reference - reference a struct ttm_buffer_object

 *

 * @bo: The buffer object.

 *

 * Returns a refcounted pointer to a buffer object.

 *

 * This function is deprecated. Use @ttm_bo_get instead.

 */



static inline struct ttm_buffer_object *

ttm_bo_reference(struct ttm_buffer_object *bo)

{

	kref_get(&bo->kref);

	ttm_bo_get(bo);

	return bo;

}
@@ -345,12 +357,23 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, 
		    struct ttm_placement *placement,

		    struct ttm_operation_ctx *ctx);



/**

 * ttm_bo_put

 *

 * @bo: The buffer object.

 *

 * Unreference a buffer object.

 */

void ttm_bo_put(struct ttm_buffer_object *bo);



/**

 * ttm_bo_unref

 *

 * @bo: The buffer object.

 *

 * Unreference and clear a pointer to a buffer object.

 *

 * This function is deprecated. Use @ttm_bo_put instead.

 */

void ttm_bo_unref(struct ttm_buffer_object **bo);