From: Jan Kara <jack@suse.cz>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "John Hubbard" <jhubbard@nvidia.com>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Christoph Hellwig" <hch@infradead.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Dave Chinner" <david@fromorbit.com>,
"David Airlie" <airlied@linux.ie>,
"David S . Miller" <davem@davemloft.net>,
"Ira Weiny" <ira.weiny@intel.com>, "Jan Kara" <jack@suse.cz>,
"Jason Gunthorpe" <jgg@ziepe.ca>, "Jens Axboe" <axboe@kernel.dk>,
"Jonathan Corbet" <corbet@lwn.net>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Michal Hocko" <mhocko@suse.com>,
"Mike Kravetz" <mike.kravetz@oracle.com>,
"Paul Mackerras" <paulus@samba.org>,
"Shuah Khan" <shuah@kernel.org>,
"Vlastimil Babka" <vbabka@suse.cz>,
bpf@vger.kernel.org, dri-devel@lists.freedesktop.org,
kvm@vger.kernel.org, linux-block@vger.kernel.org,
linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org,
linux-rdma@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
netdev@vger.kernel.org, linux-mm@kvack.org,
LKML <linux-kernel@vger.kernel.org>,
"Christoph Hellwig" <hch@lst.de>,
"Hans Verkuil" <hverkuil-cisco@xs4all.nl>,
stable@vger.kernel.org
Subject: Re: [PATCH v8 17/26] media/v4l2-core: set pages dirty upon releasing DMA buffers
Date: Tue, 10 Dec 2019 11:17:38 +0100 [thread overview]
Message-ID: <20191210101738.GE1551@quack2.suse.cz> (raw)
In-Reply-To: <20191209165627.bf657cb8fdf660e8f91e966c@linux-foundation.org>
On Mon 09-12-19 16:56:27, Andrew Morton wrote:
> On Mon, 9 Dec 2019 14:53:35 -0800 John Hubbard <jhubbard@nvidia.com> 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.
> >
> > 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>
>
> What are the user-visible effects of this change?
Presumably loss of captured video data if the page writeback hits in the
wrong moment (i.e., after the page was faulted in but before the video HW
stored data in the page) and the page then gets evicted from the page cache.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-12-10 10:17 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 22:53 [PATCH v8 00/26] mm/gup: track dma-pinned pages: FOLL_PIN John Hubbard
2019-12-09 22:53 ` [PATCH v8 01/26] mm/gup: factor out duplicate code from four routines John Hubbard
2019-12-09 22:53 ` [PATCH v8 02/26] mm/gup: move try_get_compound_head() to top, fix minor issues John Hubbard
2019-12-09 22:53 ` [PATCH v8 03/26] mm: Cleanup __put_devmap_managed_page() vs ->page_free() John Hubbard
2019-12-09 22:53 ` [PATCH v8 04/26] mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages John Hubbard
2019-12-09 22:53 ` [PATCH v8 05/26] goldish_pipe: rename local pin_user_pages() routine John Hubbard
2019-12-09 22:53 ` [PATCH v8 06/26] mm: fix get_user_pages_remote()'s handling of FOLL_LONGTERM John Hubbard
2019-12-09 22:53 ` [PATCH v8 07/26] vfio: fix FOLL_LONGTERM use, simplify get_user_pages_remote() call John Hubbard
2019-12-09 22:53 ` [PATCH v8 08/26] mm/gup: allow FOLL_FORCE for get_user_pages_fast() John Hubbard
2019-12-10 10:28 ` Jan Kara
2019-12-09 22:53 ` [PATCH v8 09/26] IB/umem: use get_user_pages_fast() to pin DMA pages John Hubbard
2019-12-09 22:53 ` [PATCH v8 10/26] mm/gup: introduce pin_user_pages*() and FOLL_PIN John Hubbard
2019-12-09 22:53 ` [PATCH v8 11/26] goldish_pipe: convert to pin_user_pages() and put_user_page() John Hubbard
2019-12-09 22:53 ` [PATCH v8 12/26] IB/{core,hw,umem}: set FOLL_PIN via pin_user_pages*(), fix up ODP John Hubbard
2019-12-09 22:53 ` [PATCH v8 13/26] mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote() John Hubbard
2019-12-09 22:53 ` [PATCH v8 14/26] drm/via: set FOLL_PIN via pin_user_pages_fast() John Hubbard
2019-12-09 22:53 ` [PATCH v8 15/26] fs/io_uring: set FOLL_PIN via pin_user_pages() John Hubbard
2019-12-09 22:53 ` [PATCH v8 16/26] net/xdp: " John Hubbard
2019-12-09 22:53 ` [PATCH v8 17/26] media/v4l2-core: set pages dirty upon releasing DMA buffers John Hubbard
2019-12-10 0:56 ` Andrew Morton
2019-12-10 5:48 ` John Hubbard
2019-12-10 10:17 ` Jan Kara [this message]
2019-12-09 22:53 ` [PATCH v8 18/26] media/v4l2-core: pin_user_pages (FOLL_PIN) and put_user_page() conversion John Hubbard
2019-12-09 22:53 ` [PATCH v8 19/26] vfio, mm: " John Hubbard
2019-12-09 22:53 ` [PATCH v8 20/26] powerpc: book3s64: convert to pin_user_pages() and put_user_page() John Hubbard
2019-12-09 23:46 ` John Hubbard
2019-12-10 5:53 ` John Hubbard
2019-12-11 0:49 ` Andrew Morton
2019-12-09 22:53 ` [PATCH v8 21/26] mm/gup_benchmark: use proper FOLL_WRITE flags instead of hard-coding "1" John Hubbard
2019-12-09 22:53 ` [PATCH v8 22/26] mm, tree-wide: rename put_user_page*() to unpin_user_page*() John Hubbard
2019-12-09 22:53 ` [PATCH v8 23/26] mm/gup: pass flags arg to __gup_device_* functions John Hubbard
2019-12-10 12:49 ` Jan Kara
2019-12-11 0:27 ` John Hubbard
2019-12-09 22:53 ` [PATCH v8 24/26] mm/gup: track FOLL_PIN pages John Hubbard
2019-12-10 13:39 ` Jan Kara
2019-12-11 0:27 ` John Hubbard
2019-12-09 22:53 ` [PATCH v8 25/26] mm/gup_benchmark: support pin_user_pages() and related calls John Hubbard
2019-12-09 22:53 ` [PATCH v8 26/26] selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage John Hubbard
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