[PATCH 1/3] drm/ttm: Provide struct ttm_global for referencing TTM global state
Daniel Vetter
daniel at ffwll.ch
Fri Oct 19 07:49:57 UTC 2018
On Fri, Oct 19, 2018 at 9:38 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>
> 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?
if (WARN_ON(!glob)
return -EINVAL;
instead of BUG_ON is much friendly for debugging. Especially in gfx
drivers, where the entire init runs while holding a few critical
kernel locks (console_lock, among others), and so will result in a
very silent death of the entire machine.
-Daniel
>
> 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
> >>
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >
>
> --
> 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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> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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