From: Jérôme Glisse <jgli...@redhat.com> Add a helper to test if call to iov_iter_get_pages*() with a given iter would result in calls to GUP (get_user_pages*()). We want to use different tracking of page references if they are coming from GUP (get_user_pages*()) and thus we need to know when GUP is used for a given iter.
Changes since Jérôme's original patch: * iov_iter_get_pages_use_gup(): do not return true for the ITER_PIPE case, because iov_iter_get_pages() calls pipe_get_pages(), which in turn uses get_page(), not get_user_pages(). * Remove some obsolete code, as part of rebasing onto Linux 5.3. * Fix up the kerneldoc comment to "Return:" rather than "Returns:", and a few other grammatical tweaks. Signed-off-by: Jérôme Glisse <jgli...@redhat.com> Signed-off-by: John Hubbard <jhubb...@nvidia.com> Cc: linux-fsde...@vger.kernel.org Cc: linux-block@vger.kernel.org Cc: linux...@kvack.org Cc: John Hubbard <jhubb...@nvidia.com> Cc: Jan Kara <j...@suse.cz> Cc: Dan Williams <dan.j.willi...@intel.com> Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: Johannes Thumshirn <jthumsh...@suse.de> Cc: Christoph Hellwig <h...@lst.de> Cc: Jens Axboe <ax...@kernel.dk> Cc: Ming Lei <ming....@redhat.com> Cc: Dave Chinner <da...@fromorbit.com> Cc: Jason Gunthorpe <j...@ziepe.ca> Cc: Matthew Wilcox <wi...@infradead.org> --- include/linux/uio.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/include/linux/uio.h b/include/linux/uio.h index ab5f523bc0df..2a179af8e5a7 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -86,6 +86,17 @@ static inline unsigned char iov_iter_rw(const struct iov_iter *i) return i->type & (READ | WRITE); } +/** + * iov_iter_get_pages_use_gup - report if iov_iter_get_pages(i) uses GUP + * @i: iterator + * Return: true if a call to iov_iter_get_pages*() with the iter provided in + * the argument would result in the use of get_user_pages*() + */ +static inline bool iov_iter_get_pages_use_gup(const struct iov_iter *i) +{ + return iov_iter_type(i) == ITER_IOVEC; +} + /* * Total number of bytes covered by an iovec. * -- 2.22.0