From: John Hubbard <jhubbard@nvidia.com>
Date: Fri, 31 Jan 2020 06:12:50 +0000 (-0800)
Subject: media/v4l2-core: set pages dirty upon releasing DMA buffers
X-Git-Tag: v5.6-rc1~100^2~85
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=3c7470b6f68434acae459482ab920d1e3fabd1c7;p=linux-2.6-block.git

media/v4l2-core: set pages dirty upon releasing DMA buffers

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.

Link: http://lkml.kernel.org/r/20200107224558.2362728-11-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
index 66a6c6c236a7..28262190c3ab 100644
--- a/drivers/media/v4l2-core/videobuf-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -349,8 +349,11 @@ int videobuf_dma_free(struct videobuf_dmabuf *dma)
 	BUG_ON(dma->sglen);
 
 	if (dma->pages) {
-		for (i = 0; i < dma->nr_pages; i++)
+		for (i = 0; i < dma->nr_pages; i++) {
+			if (dma->direction == DMA_FROM_DEVICE)
+				set_page_dirty_lock(dma->pages[i]);
 			put_page(dma->pages[i]);
+		}
 		kfree(dma->pages);
 		dma->pages = NULL;
 	}