new primitive: iov_iter_for_each_range()
For kvec and bvec: feeds segments to given callback as long as it
returns 0. For iovec and pipe: fails.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 5885dae..e67e12a 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -244,4 +244,8 @@ int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
int import_single_range(int type, void __user *buf, size_t len,
struct iovec *iov, struct iov_iter *i);
+int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
+ int (*f)(struct kvec *vec, void *context),
+ void *context);
+
#endif