[PATCH] drm/amdgpu: fix userptr put_page handling

[Felix Kuehling]

Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>


On 2017-09-02 07:22 AM, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
>
> Move calling put_page into the unpopulate callback. Otherwise we mess up the pages
> reference count when it is unbound multiple times.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h     |  1 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c  |  6 ++----
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 14 +++++++++++++-
>  3 files changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 21cab36..4dc9744 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1802,6 +1802,7 @@ void amdgpu_cs_report_moved_bytes(struct amdgpu_device *adev, u64 num_bytes,
>  void amdgpu_ttm_placement_from_domain(struct amdgpu_bo *abo, u32 domain);
>  bool amdgpu_ttm_bo_is_amdgpu_bo(struct ttm_buffer_object *bo);
>  int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages);
> +void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages);
>  int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
>  				     uint32_t flags);
>  bool amdgpu_ttm_tt_has_userptr(struct ttm_tt *ttm);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 48e18cc..c3202c8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -471,10 +471,8 @@ static int amdgpu_cs_list_validate(struct amdgpu_cs_parser *p,
>  
>  		/* Check if we have user pages and nobody bound the BO already */
>  		if (lobj->user_pages && bo->tbo.ttm->state != tt_bound) {
> -			size_t size = sizeof(struct page *);
> -
> -			size *= bo->tbo.ttm->num_pages;
> -			memcpy(bo->tbo.ttm->pages, lobj->user_pages, size);
> +			amdgpu_ttm_tt_set_user_pages(bo->tbo.ttm,
> +						     lobj->user_pages);
>  			binding_userptr = true;
>  		}
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index ac14c18..07c3f11 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -664,6 +664,18 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
>  	return r;
>  }
>  
> +void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages)
> +{
> +	unsigned i;
> +
> +	for (i = 0; i < ttm->num_pages; ++i) {
> +		if (ttm->pages[i])
> +			put_page(ttm->pages[i]);
> +
> +		ttm->pages[i] = pages ? pages[i] : NULL;
> +	}
> +}
> +
>  static void amdgpu_trace_dma_map(struct ttm_tt *ttm)
>  {
>  	struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
> @@ -738,7 +750,6 @@ static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
>  			set_page_dirty(page);
>  
>  		mark_page_accessed(page);
> -		put_page(page);
>  	}
>  
>  	amdgpu_trace_dma_unmap(ttm);
> @@ -971,6 +982,7 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_tt *ttm)
>  	bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
>  
>  	if (gtt && gtt->userptr) {
> +		amdgpu_ttm_tt_set_user_pages(ttm, NULL);
>  		kfree(ttm->sg);
>  		ttm->page_flags &= ~TTM_PAGE_FLAG_SG;
>  		return;