linux-kernel - Re: [PATCH v3 9/9] xen/gntdev: Implement dma-buf import functionality

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Date:   Tue, 12 Jun 2018 23:14:42 -0400
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     Oleksandr Andrushchenko <andr2000@...il.com>,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-media@...r.kernel.org,
        jgross@...e.com, konrad.wilk@...cle.com
Cc:     daniel.vetter@...el.com, dongwon.kim@...el.com,
        matthew.d.roper@...el.com,
        Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
Subject: Re: [PATCH v3 9/9] xen/gntdev: Implement dma-buf import functionality



On 06/12/2018 09:42 AM, Oleksandr Andrushchenko wrote:

>   int gntdev_dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd)
>   {
> -	return -EINVAL;
> +	struct gntdev_dmabuf *gntdev_dmabuf;
> +	struct dma_buf_attachment *attach;
> +	struct dma_buf *dma_buf;
> +
> +	gntdev_dmabuf = dmabuf_imp_find_unlink(priv, fd);
> +	if (IS_ERR(gntdev_dmabuf))
> +		return PTR_ERR(gntdev_dmabuf);
> +
> +	pr_debug("Releasing DMA buffer with fd %d\n", fd);
> +
> +	attach = gntdev_dmabuf->u.imp.attach;
> +
> +	if (gntdev_dmabuf->u.imp.sgt)
> +		dma_buf_unmap_attachment(attach, gntdev_dmabuf->u.imp.sgt,
> +					 DMA_BIDIRECTIONAL);
> +	dma_buf = attach->dmabuf;
> +	dma_buf_detach(attach->dmabuf, attach);
> +	dma_buf_put(dma_buf);
> +
> +	dmabuf_imp_end_foreign_access(gntdev_dmabuf->u.imp.refs,
> +				      gntdev_dmabuf->nr_pages);



Should you first end foreign access, before doing anything?

-boris


> +	dmabuf_imp_free_storage(gntdev_dmabuf);
> +	return 0;
>   }
>