From: Jérôme Glisse <[email protected]> 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 <[email protected]> Signed-off-by: John Hubbard <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: John Hubbard <[email protected]> Cc: Jan Kara <[email protected]> Cc: Dan Williams <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Johannes Thumshirn <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Ming Lei <[email protected]> Cc: Dave Chinner <[email protected]> Cc: Jason Gunthorpe <[email protected]> Cc: Matthew Wilcox <[email protected]> --- 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 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
