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Date:   Wed, 16 Mar 2022 10:54:51 +0100
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Subject: Re: [RFC PATCH 5/7] drm/ttm: add range busy check for range manager
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To:     Robert Beckett <bob.beckett@collabora.com>,
        intel-gfx@lists.freedesktop.org, Huang Rui <ray.huang@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>
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References: <20220315180444.3327283-1-bob.beckett@collabora.com>
 <20220315180444.3327283-6-bob.beckett@collabora.com>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
In-Reply-To: <20220315180444.3327283-6-bob.beckett@collabora.com>
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Am 15.03.22 um 19:04 schrieb Robert Beckett:
> RFC: do we want this to become a generic interface in
> ttm_resource_manager_func?
>
> RFC: would we prefer a different interface? e.g.
> for_each_resource_in_range or for_each_bo_in_range

Well completely NAK to that. Why do you need that?

The long term goal is to completely remove the range checks from TTM 
instead.

Regards,
Christian.

>
> Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
> ---
>   drivers/gpu/drm/ttm/ttm_range_manager.c | 21 +++++++++++++++++++++
>   include/drm/ttm/ttm_range_manager.h     |  3 +++
>   2 files changed, 24 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c b/drivers/gpu/drm/ttm/ttm_range_manager.c
> index 8cd4f3fb9f79..5662627bb933 100644
> --- a/drivers/gpu/drm/ttm/ttm_range_manager.c
> +++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
> @@ -206,3 +206,24 @@ int ttm_range_man_fini_nocheck(struct ttm_device *bdev,
>   	return 0;
>   }
>   EXPORT_SYMBOL(ttm_range_man_fini_nocheck);
> +
> +/**
> + * ttm_range_man_range_busy - Check whether anything is allocated with a range
> + *
> + * @man: memory manager to check
> + * @fpfn: first page number to check
> + * @lpfn: last page number to check
> + *
> + * Return: true if anything allocated within the range, false otherwise.
> + */
> +bool ttm_range_man_range_busy(struct ttm_resource_manager *man,
> +			      unsigned fpfn, unsigned lpfn)
> +{
> +	struct ttm_range_manager *rman = to_range_manager(man);
> +	struct drm_mm *mm = &rman->mm;
> +
> +	if (__drm_mm_interval_first(mm, PFN_PHYS(fpfn), PFN_PHYS(lpfn + 1) - 1))
> +		return true;
> +	return false;
> +}
> +EXPORT_SYMBOL(ttm_range_man_range_busy);
> diff --git a/include/drm/ttm/ttm_range_manager.h b/include/drm/ttm/ttm_range_manager.h
> index 7963b957e9ef..86794a3f9101 100644
> --- a/include/drm/ttm/ttm_range_manager.h
> +++ b/include/drm/ttm/ttm_range_manager.h
> @@ -53,4 +53,7 @@ static __always_inline int ttm_range_man_fini(struct ttm_device *bdev,
>   	BUILD_BUG_ON(__builtin_constant_p(type) && type >= TTM_NUM_MEM_TYPES);
>   	return ttm_range_man_fini_nocheck(bdev, type);
>   }
> +
> +bool ttm_range_man_range_busy(struct ttm_resource_manager *man,
> +			      unsigned fpfn, unsigned lpfn);
>   #endif