diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7617ee04f066e7b2852f95c0b1b690b2a92f533b..7d2e893ec3d1903ed4600a00a39221cd14fa3beb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -301,7 +301,7 @@ size_t iov_iter_copy_from_user(struct page *page,
 		struct iov_iter *i, unsigned long offset, size_t bytes);
 void iov_iter_advance(struct iov_iter *i, size_t bytes);
 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
-size_t iov_iter_single_seg_count(struct iov_iter *i);
+size_t iov_iter_single_seg_count(const struct iov_iter *i);
 
 static inline void iov_iter_init(struct iov_iter *i,
 			const struct iovec *iov, unsigned long nr_segs,
diff --git a/mm/filemap.c b/mm/filemap.c
index 83efee76a5c0b12c577903346eca32f7ca49be18..24a7ea583f0cf4039525d824ac047f5f9d7eddb0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2056,7 +2056,7 @@ EXPORT_SYMBOL(iov_iter_fault_in_readable);
 /*
  * Return the count of just the current iov_iter segment.
  */
-size_t iov_iter_single_seg_count(struct iov_iter *i)
+size_t iov_iter_single_seg_count(const struct iov_iter *i)
 {
 	const struct iovec *iov = i->iov;
 	if (i->nr_segs == 1)