From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 23 Sep 2017 16:24:59 -0400
Subject: [PATCH] bio_map_user_iov(): get rid of the iov_for_each()
Git-commit: b282cc766958af161249b7b04d50e3eae12a2a1c
Patch-mainline: v4.15-rc1
References: bsc#1104967,FATE#325924

Use iov_iter_npages()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/bio.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index d851f68727f1..d1ca7eecc8aa 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1324,32 +1324,15 @@ struct bio *bio_map_user_iov(struct request_queue *q,
 			     gfp_t gfp_mask)
 {
 	int j;
-	int nr_pages = 0;
 	struct bio *bio;
 	int ret;
 	struct iov_iter i;
-	struct iovec iov;
 	struct bio_vec *bvec;
 
-	iov_for_each(iov, i, *iter) {
-		unsigned long uaddr = (unsigned long) iov.iov_base;
-		unsigned long len = iov.iov_len;
-		unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-		unsigned long start = uaddr >> PAGE_SHIFT;
-
-		/*
-		 * Overflow, abort
-		 */
-		if (end < start)
-			return ERR_PTR(-EINVAL);
-
-		nr_pages += end - start;
-	}
-
-	if (!nr_pages)
+	if (!iov_iter_count(iter))
 		return ERR_PTR(-EINVAL);
 
-	bio = bio_kmalloc(gfp_mask, nr_pages);
+	bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES));
 	if (!bio)
 		return ERR_PTR(-ENOMEM);
 
-- 
2.16.4