[033/118] media/v4l2-core: set pages dirty upon releasing DMA buffers

Commit Message

Andrew Morton Jan. 31, 2020, 6:12 a.m. UTC

From: John Hubbard <[e-mail]>
Subject: 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/[e-mail]
Signed-off-by: John Hubbard <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Acked-by: Hans Verkuil <[e-mail]>
Cc: Mauro Carvalho Chehab <[e-mail]>
Cc: <[e-mail]>
Cc: Alex Williamson <[e-mail]>
Cc: Aneesh Kumar K.V <[e-mail]>
Cc: Björn Töpel <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Dan Williams <[e-mail]>
Cc: Ira Weiny <[e-mail]>
Cc: Jan Kara <[e-mail]>
Cc: Jason Gunthorpe <[e-mail]>
Cc: Jason Gunthorpe <[e-mail]>
Cc: Jens Axboe <[e-mail]>
Cc: Jerome Glisse <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Kirill A. Shutemov <[e-mail]>
Cc: Leon Romanovsky <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 drivers/media/v4l2-core/videobuf-dma-sg.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Patch

--- a/drivers/media/v4l2-core/videobuf-dma-sg.c~media-v4l2-core-set-pages-dirty-upon-releasing-dma-buffers
+++ a/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -349,8 +349,11 @@  int videobuf_dma_free(struct videobuf_dm
 	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;
 	}