# Re: \[PATCH v7 08/24\] media/v4l2-core: set pages dirty upon releasing DMA buffers

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2019-11-21 08:11:10 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2019/11/167356
- Thread: https://ratatoskr.run/bpf/2019/11/167331/t.md

```text
On Wed, Nov 20, 2019 at 11:13:38PM -0800, John Hubbard wrote:
> After DMA is complete, and the device and CPU caches are synchronized,
> it's still required to mark the CPU pages as dirty, if the data was
> coming from the device. However, this driver was just issuing a
> bare put_page() call, without any set_page_dirty*() call.
> 
> Fix the problem, by calling set_page_dirty_lock() if the CPU pages
> were potentially receiving data from the device.

Looks good, and like a fix that should be queued up through the media
tree for 5.5 and maybe even added to -stable.

Reviewed-by: Christoph Hellwig <hch@lst.de>
```