Re: [PATCH v1 15/15] ceph: use put_user_pages() instead of ceph_put_page_vector()

Yan, Zheng
2019-04-15T07:47:16Z

On 4/12/19 5:08 AM, jglisse@redhat.com wrote:
> From: Jérôme Glisse <jglisse@redhat.com>
>
> When page reference were taken through GUP (get_user_page*()) we need
> to drop them with put_user_pages().
>
> Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
> Cc: linux-fsdevel@vger.kernel.org
> Cc: linux-block@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: Johannes Thumshirn <jthumshirn@suse.de>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Dave Chinner <david@fromorbit.com>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Yan Zheng <zyan@redhat.com>
> Cc: Sage Weil <sage@redhat.com>
> Cc: Ilya Dryomov <idryomov@gmail.com>
> Cc: ceph-devel@vger.kernel.org
> ---
> fs/ceph/file.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 6c5b85f01721..5842ad3a4218 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -667,7 +667,8 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
> } else {
> iov_iter_advance(to, 0);
> }
> - ceph_put_page_vector(pages, num_pages, false);
> + /* iov_iter_get_pages_alloc() did call GUP */
> + put_user_pages(pages, num_pages);

pages in pipe were not from get_user_pages(). Am I missing anything?

Regards
Yan, Zheng

> } else {
> int idx = 0;
> size_t left = ret > 0 ? ret : 0;
>