linux-kernel - Re: [PATCH] dma-buf: Make mmap callback actually optional

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Message-ID: <24aa0897-8f23-f747-d9a4-d5272f37beea@gmail.com>
Date:   Mon, 1 Apr 2019 15:38:36 +0200
From:   Christian König <ckoenig.leichtzumerken@...il.com>
To:     "Andrew F. Davis" <afd@...com>,
        Sumit Semwal <sumit.semwal@...aro.org>
Cc:     linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] dma-buf: Make mmap callback actually optional

Am 29.03.19 um 17:52 schrieb Andrew F. Davis:
> The docs state the callback is optional but it is not, make it optional.
>
> Signed-off-by: Andrew F. Davis <afd@...com>

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

> ---
>   drivers/dma-buf/dma-buf.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 7c858020d14b..4d4ae9fe9ac8 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -90,6 +90,10 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
>   
>   	dmabuf = file->private_data;
>   
> +	/* check if buffer supports mmap */
> +	if (!dmabuf->ops->mmap)
> +		return -EINVAL;
> +
>   	/* check for overflowing the buffer's size */
>   	if (vma->vm_pgoff + vma_pages(vma) >
>   	    dmabuf->size >> PAGE_SHIFT)
> @@ -404,8 +408,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
>   			  || !exp_info->ops
>   			  || !exp_info->ops->map_dma_buf
>   			  || !exp_info->ops->unmap_dma_buf
> -			  || !exp_info->ops->release
> -			  || !exp_info->ops->mmap)) {
> +			  || !exp_info->ops->release)) {
>   		return ERR_PTR(-EINVAL);
>   	}
>   
> @@ -906,6 +909,10 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
>   	if (WARN_ON(!dmabuf || !vma))
>   		return -EINVAL;
>   
> +	/* check if buffer supports mmap */
> +	if (!dmabuf->ops->mmap)
> +		return -EINVAL;
> +
>   	/* check for offset overflow */
>   	if (pgoff + vma_pages(vma) < pgoff)
>   		return -EOVERFLOW;