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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: Thomas Zimmermann <contact@tzimmermann.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Thomas Zimmermann 2018-06-21 15:21:35 +02:00 committed by Alex Deucher
parent 31e1c59796
commit 89c815ef07
2 changed files with 31 additions and 2 deletions
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8
drivers/gpu/drm/ttm/ttm_bo.c
View File

@ -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);

25
include/drm/ttm/ttm_bo_api.h
View File

@ -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);