Hi Tomasz,
Thanks for the patch.
On Wednesday 10 October 2012 16:46:40 Tomasz Stanislawski wrote:
> This patch adds taking reference to the device for MMAP buffers.
>
> Such buffers, may be exported using DMABUF mechanism. If the driver that
> created a queue is unloaded then the queue is released, the device might be
> released too. However, buffers cannot be released if they are referenced by
> DMABUF descriptor(s). The device pointer kept in a buffer must be valid for
> the whole buffer's lifetime. Therefore MMAP buffers should take a reference
> to the device to avoid risk of dangling pointers.
>
> Signed-off-by: Tomasz Stanislawski <t.stanisl...@samsung.com>
> Acked-by: Hans Verkuil <hans.verk...@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
But two small comments below.
> ---
> drivers/media/v4l2-core/videobuf2-dma-contig.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b138b5c..2d661fd
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv)
> kfree(buf->sgt_base);
> }
> dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
> + put_device(buf->dev);
> kfree(buf);
> }
>
> @@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long
> size) return ERR_PTR(-ENOMEM);
> }
>
> + /* prevent the device from release while the buffer is exported */
s/prevent/Prevent/ ?
> + get_device(dev);
> +
> buf->dev = dev;
What about just
buf->dev = get_device(dev);
> buf->size = size;
--
Regards,
Laurent Pinchart
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