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,