From a6294593e8a1290091d0b078d5d33da5e0cd3dfe Mon Sep 17 00:00:00 2001
From: Andreas Gruenbacher <agruenba@redhat.com>
Date: Mon, 2 Aug 2021 14:54:16 +0200
Subject: [Backport a6294593e8a1] iov_iter: Turn iov_iter_fault_in_readable
 into fault_in_iov_iter_readable

Turn iov_iter_fault_in_readable into a function that returns the number
of bytes not faulted in, similar to copy_to_user, instead of returning a
non-zero value when any of the requested pages couldn't be faulted in.
This supports the existing users that require all pages to be faulted in
as well as new users that are happy if any pages can be faulted in.

Rename iov_iter_fault_in_readable to fault_in_iov_iter_readable to make
sure this change doesn't silently break things.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 src/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/file.c b/src/file.c
index 424450e77ad52ae550e8de444dc393411d97cde6..a52388387175ac6ed8bfa31ee1af0c78455582be 100644
--- a/src/file.c
+++ b/src/file.c
@@ -987,7 +987,7 @@ static ssize_t ntfs_compress_write(struct kiocb *iocb, struct iov_iter *from)
 		frame_vbo = pos & ~(frame_size - 1);
 		index = frame_vbo >> PAGE_SHIFT;
 
-		if (unlikely(iov_iter_fault_in_readable(from, bytes))) {
+		if (unlikely(fault_in_iov_iter_readable(from, bytes))) {
 			err = -EFAULT;
 			goto out;
 		}
-- 
2.31.1