linux-kernel - Re: [PATCH] drm/ttm: remove cpu_address member from ttm

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Date:   Fri, 16 Sep 2016 11:43:48 +0200
From:   Christian König <deathsimple@...afone.de>
To:     Alexandre Courbot <acourbot@...dia.com>,
        David Airlie <airlied@...ux.ie>
Cc:     gnurou@...il.com, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/ttm: remove cpu_address member from ttm_tt

Am 16.09.2016 um 11:32 schrieb Alexandre Courbot:
> Patch 3d50d4dcb0 exposed the CPU address of DMA-allocated pages as
> returned by dma_alloc_coherent because Nouveau on Tegra needed it.
>
> This is not required anymore - as there were no other users for it,
> remove it and save some memory for everyone.
>
> Signed-off-by: Alexandre Courbot <acourbot@...dia.com>

Reviewed-by: Christian König <christian.koenig@....com>.

> ---
>   drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 2 --
>   drivers/gpu/drm/ttm/ttm_tt.c             | 7 ++-----
>   include/drm/ttm/ttm_bo_driver.h          | 2 --
>   3 files changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> index bef9f6feb635..cec4b4baa179 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> @@ -858,7 +858,6 @@ static int ttm_dma_pool_get_pages(struct dma_pool *pool,
>   	if (count) {
>   		d_page = list_first_entry(&pool->free_list, struct dma_page, page_list);
>   		ttm->pages[index] = d_page->p;
> -		ttm_dma->cpu_address[index] = d_page->vaddr;
>   		ttm_dma->dma_address[index] = d_page->dma;
>   		list_move_tail(&d_page->page_list, &ttm_dma->pages_list);
>   		r = 0;
> @@ -989,7 +988,6 @@ void ttm_dma_unpopulate(struct ttm_dma_tt *ttm_dma, struct device *dev)
>   	INIT_LIST_HEAD(&ttm_dma->pages_list);
>   	for (i = 0; i < ttm->num_pages; i++) {
>   		ttm->pages[i] = NULL;
> -		ttm_dma->cpu_address[i] = 0;
>   		ttm_dma->dma_address[i] = 0;
>   	}
>   
> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> index bc5aa573f466..aee3c00f836e 100644
> --- a/drivers/gpu/drm/ttm/ttm_tt.c
> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> @@ -57,10 +57,8 @@ static void ttm_dma_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
>   {
>   	ttm->ttm.pages = drm_calloc_large(ttm->ttm.num_pages,
>   					  sizeof(*ttm->ttm.pages) +
> -					  sizeof(*ttm->dma_address) +
> -					  sizeof(*ttm->cpu_address));
> -	ttm->cpu_address = (void *) (ttm->ttm.pages + ttm->ttm.num_pages);
> -	ttm->dma_address = (void *) (ttm->cpu_address + ttm->ttm.num_pages);
> +					  sizeof(*ttm->dma_address));
> +	ttm->dma_address = (void *) (ttm->ttm.pages + ttm->ttm.num_pages);
>   }
>   
>   #ifdef CONFIG_X86
> @@ -244,7 +242,6 @@ void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
>   
>   	drm_free_large(ttm->pages);
>   	ttm->pages = NULL;
> -	ttm_dma->cpu_address = NULL;
>   	ttm_dma->dma_address = NULL;
>   }
>   EXPORT_SYMBOL(ttm_dma_tt_fini);
> diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
> index c986fa7effd2..4f0a92185995 100644
> --- a/include/drm/ttm/ttm_bo_driver.h
> +++ b/include/drm/ttm/ttm_bo_driver.h
> @@ -133,7 +133,6 @@ struct ttm_tt {
>    * struct ttm_dma_tt
>    *
>    * @ttm: Base ttm_tt struct.
> - * @cpu_address: The CPU address of the pages
>    * @dma_address: The DMA (bus) addresses of the pages
>    * @pages_list: used by some page allocation backend
>    *
> @@ -143,7 +142,6 @@ struct ttm_tt {
>    */
>   struct ttm_dma_tt {
>   	struct ttm_tt ttm;
> -	void **cpu_address;
>   	dma_addr_t *dma_address;
>   	struct list_head pages_list;
>   };