From fcb14cb1bdacec5b4374fe161e83fb8208164a85 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 22 May 2022 14:59:25 -0400 Subject: new iov_iter flavour - ITER_UBUF Equivalent of single-segment iovec. Initialized by iov_iter_ubuf(), checked for by iter_is_ubuf(), otherwise behaves like ITER_IOVEC ones. We are going to expose the things like ->write_iter() et.al. to those in subsequent commits. New predicate (user_backed_iter()) that is true for ITER_IOVEC and ITER_UBUF; places like direct-IO handling should use that for checking that pages we modify after getting them from iov_iter_get_pages() would need to be dirtied. DO NOT assume that replacing iter_is_iovec() with user_backed_iter() will solve all problems - there's code that uses iter_is_iovec() to decide how to poke around in iov_iter guts and for that the predicate replacement obviously won't suffice. Signed-off-by: Al Viro --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/shmem.c b/mm/shmem.c index e5e43b990fdc..e3a7e171bbd1 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2602,7 +2602,7 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) ret = copy_page_to_iter(page, offset, nr, to); put_page(page); - } else if (iter_is_iovec(to)) { + } else if (user_backed_iter(to)) { /* * Copy to user tends to be so well optimized, but * clear_user() not so much, that it is noticeably -- cgit v1.2.3-59-g8ed1b