[PATCH RESEND] iov_iter: Use user_read_access_begin() instead of user_access_begin()

[Christophe Leroy]

copy_compat_iovec_from_user() only do unsafe_get_user(),
it only requires read access.

Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
---
Resending with mm list in addition

 lib/iov_iter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 61228a6c69f8..fd9bd229d51d 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1932,7 +1932,7 @@ static int copy_compat_iovec_from_user(struct iovec *iov,
 		(const struct compat_iovec __user *)uvec;
 	int ret = -EFAULT, i;
 
-	if (!user_access_begin(uiov, nr_segs * sizeof(*uiov)))
+	if (!user_read_access_begin(uiov, nr_segs * sizeof(*uiov)))
 		return -EFAULT;
 
 	for (i = 0; i < nr_segs; i++) {
@@ -1953,7 +1953,7 @@ static int copy_compat_iovec_from_user(struct iovec *iov,
 
 	ret = 0;
 uaccess_end:
-	user_access_end();
+	user_read_access_end();
 	return ret;
 }
 
-- 
2.25.0