linux-kernel - Re: [RFC][PATCH 14/15] videobuf2: don't test db

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Message-ID: <8d79287c-d868-37cc-85f1-89cf5d8b92a9@xs4all.nl>
Date:   Fri, 10 Jan 2020 11:32:42 +0100
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Tomasz Figa <tfiga@...omium.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     Sakari Ailus <sakari.ailus@....fi>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Pawel Osciak <posciak@...omium.org>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH 14/15] videobuf2: don't test db_attach in dma-contig
 prepare and finish

On 12/17/19 4:20 AM, Sergey Senozhatsky wrote:
> We moved cache management decision making to the upper layer and
> rely on buffer's need_cache_sync flags and videobuf2 core. If the
> upper layer (core) has decided to invoke ->prepare() or ->finish()
> then we must sync.
> 
> For DMABUF ->need_cache_sync_on_prepare and ->need_cache_sync_on_flush
> are always false so videobuf core does not call ->prepare() and
> ->finish() on such buffers.
> 
> Additionally, scratch the DMABUF comment.

Just combine this and the next patch into a single patch. No need to
split this up.

Regards,

	Hans

> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
> ---
>  drivers/media/common/videobuf2/videobuf2-dma-contig.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index a387260fb321..6ea0961149d7 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -100,8 +100,7 @@ static void vb2_dc_prepare(void *buf_priv)
>  	struct vb2_dc_buf *buf = buf_priv;
>  	struct sg_table *sgt = buf->dma_sgt;
>  
> -	/* DMABUF exporter will flush the cache for us */
> -	if (!sgt || buf->db_attach)
> +	if (!sgt)
>  		return;
>  
>  	dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
> @@ -113,8 +112,7 @@ static void vb2_dc_finish(void *buf_priv)
>  	struct vb2_dc_buf *buf = buf_priv;
>  	struct sg_table *sgt = buf->dma_sgt;
>  
> -	/* DMABUF exporter will flush the cache for us */
> -	if (!sgt || buf->db_attach)
> +	if (!sgt)
>  		return;
>  
>  	dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
>