First, convert set_page_dirty() to set_page_dirty_lock()
Second, there is an interval in there after set_page_dirty() and
before put_page(), in which the device could be running and setting
pages dirty. Moving set_page_dirty_lock() after dma_unmap_sg().
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Suggested-by: John Hubbard <jhubbard@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Bharath Vedartham <linux.bhar@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/1593584264-16982-3-git-send-email-jrdr.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 
        BUG_ON(!acd->ldev);
        BUG_ON(!acd->ldev->pldev);
 
+       dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
+
        for (i = 0 ; i < acd->page_count ; i++) {
                if (!PageReserved(acd->user_pages[i]))
-                       set_page_dirty(acd->user_pages[i]);
+                       set_page_dirty_lock(acd->user_pages[i]);
        }
 
-       dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
-
        for (i = 0 ; i < acd->page_count ; i++)
                put_page(acd->user_pages[i]);