[PATCH 1/3] drm/ttm: Provide struct ttm_global for referencing TTM global state

Fri Oct 19 07:38:15 UTC 2018

Hi,

thanks for the review.

Am 19.10.18 um 05:30 schrieb Huang Rui:
> On Fri, Oct 19, 2018 at 12:27:50AM +0800, Thomas Zimmermann wrote:
>> +int ttm_global_init(struct ttm_global *glob)
>> +{
>> +	int ret;
>> +
> 
> We would better add a protection here to make sure the glob is not NULL.
> 
> if (!glob)
>         return -EINVAL;

Passing a NULL pointer is a programming error, not a runtime error. I'd
rather use BUG_ON() for this test. Ok?

Best regards
Thomas

> 
> Others, look good for me.
> 
> Thanks,
> Ray
> 
>> +	glob->mem_ref.global_type = DRM_GLOBAL_TTM_MEM;
>> +	glob->mem_ref.size = sizeof(struct ttm_mem_global);
>> +	glob->bo_ref.object = NULL;
>> +	glob->mem_ref.init = &ttm_global_init_mem;
>> +	glob->mem_ref.release = &ttm_global_release_mem;
>> +	ret = drm_global_item_ref(&glob->mem_ref);
>> +	if (ret)
>> +		return ret;
>> +
>> +	glob->bo_ref.global_type = DRM_GLOBAL_TTM_BO;
>> +	glob->bo_ref.size = sizeof(struct ttm_bo_global);
>> +	glob->bo_ref.object = NULL;
>> +	glob->bo_ref.init = &ttm_global_init_bo;
>> +	glob->bo_ref.release = &ttm_global_release_bo;
>> +	ret = drm_global_item_ref(&glob->bo_ref);
>> +	if (ret)
>> +		goto err_drm_global_item_unref_mem;
>> +
>> +	return 0;
>> +
>> +err_drm_global_item_unref_mem:
>> +	drm_global_item_unref(&glob->mem_ref);
>> +	return ret;
>> +}
>> +
>> +EXPORT_SYMBOL(ttm_global_init);
>> +
>> +void ttm_global_release(struct ttm_global *glob)
>> +{
>> +	drm_global_item_unref(&glob->bo_ref);
>> +	drm_global_item_unref(&glob->mem_ref);
>> +}
>> +
>> +EXPORT_SYMBOL(ttm_global_release);
>> diff --git a/include/drm/drm_global.h b/include/drm/drm_global.h
>> index 3a830602a2e4..4482a9bbd6e9 100644
>> --- a/include/drm/drm_global.h
>> +++ b/include/drm/drm_global.h
>> @@ -28,8 +28,16 @@
>>   * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
>>   */
>>  
>> +/*
>> + *  The interfaces in this file are deprecated. Please use ttm_global
>> + *  from <drm/ttm/ttm_global.h> instead.
>> + */
>> +
>>  #ifndef _DRM_GLOBAL_H_
>>  #define _DRM_GLOBAL_H_
>> +
>> +#include <linux/types.h>
>> +
>>  enum drm_global_types {
>>  	DRM_GLOBAL_TTM_MEM = 0,
>>  	DRM_GLOBAL_TTM_BO,
>> diff --git a/include/drm/ttm/ttm_global.h b/include/drm/ttm/ttm_global.h
>> new file mode 100644
>> index 000000000000..06e791499f87
>> --- /dev/null
>> +++ b/include/drm/ttm/ttm_global.h
>> @@ -0,0 +1,79 @@
>> +/**************************************************************************
>> + *
>> + * Copyright 2008-2009 VMware, Inc., Palo Alto, CA., USA
>> + * All Rights Reserved.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the
>> + * "Software"), to deal in the Software without restriction, including
>> + * without limitation the rights to use, copy, modify, merge, publish,
>> + * distribute, sub license, and/or sell copies of the Software, and to
>> + * permit persons to whom the Software is furnished to do so, subject to
>> + * the following conditions:
>> + *
>> + * The above copyright notice and this permission notice (including the
>> + * next paragraph) shall be included in all copies or substantial portions
>> + * of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
>> + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
>> + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
>> + * USE OR OTHER DEALINGS IN THE SOFTWARE.
>> + *
>> + **************************************************************************/
>> +
>> +#ifndef _TTM_GLOBAL_H_
>> +#define _TTM_GLOBAL_H_
>> +
>> +#include <drm/drm_global.h>
>> +
>> +struct ttm_bo_global;
>> +
>> +/**
>> + * struct ttm_global - Stores references to global TTM state
>> + */
>> +struct ttm_global {
>> +	struct drm_global_reference mem_ref;
>> +	struct drm_global_reference bo_ref;
>> +};
>> +
>> +/**
>> + * ttm_global_init
>> + *
>> + * @glob: A pointer to a struct ttm_global that is about to be initialized
>> + * @return Zero on success, or a negative error code otherwise.
>> + *
>> + * Initializes an instance of struct ttm_global with TTM's global state
>> + */
>> +int ttm_global_init(struct ttm_global *glob);
>> +
>> +/**
>> + * ttm_global_release
>> + *
>> + * @glob: A pointer to an instance of struct ttm_global
>> + *
>> + * Releases an initialized instance of struct ttm_global. If the instance
>> + * constains the final references to the global memory and BO, the global
>> + * structures are released as well.
>> + */
>> +void ttm_global_release(struct ttm_global *glob);
>> +
>> +/**
>> + * ttm_global_get_bo_global
>> + *
>> + * @glob A pointer to an instance of struct ttm_global
>> + * @return A refernce to the global BO.
>> + *
>> + * Returns the global BO. The BO should be forwarded to the initialization
>> + * of a driver's TTM BO device.
>> + */
>> +static inline struct ttm_bo_global*
>> +ttm_global_get_bo_global(struct ttm_global *glob)
>> +{
>> +	return glob->bo_ref.object;
>> +}
>> +
>> +#endif /* _TTM_GLOBAL_H_ */
>> -- 
>> 2.19.1
>>
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> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Linux GmbH, Maxfeldstr. 5, D-90409 Nürnberg
Tel: +49-911-74053-0; Fax: +49-911-7417755;  https://www.suse.com/
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard,
Graham Norton, HRB 21284 (AG Nürnberg)

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