2 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 5885daeae721..e67e12adb136 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
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 1c1c06ddc20a..970212670b6a 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1446,3 +1446,25 @@ int import_single_range(int rw, void __user *buf, size_t len,
         return 0;
 }
 EXPORT_SYMBOL(import_single_range);
+
+int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
+                            int (*f)(struct kvec *vec, void *context),
+                            void *context)
+{
+        struct kvec w;
+        int err = -EINVAL;
+        if (!bytes)
+                return 0;
+
+        iterate_all_kinds(i, bytes, v, -EINVAL, ({
+                w.iov_base = kmap(v.bv_page) + v.bv_offset;
+                w.iov_len = v.bv_len;
+                err = f(&w, context);
+                kunmap(v.bv_page);
+                err;}), ({
+                w = v;
+                err = f(&w, context);})
+        )
+        return err;
+}
+EXPORT_SYMBOL(iov_iter_for_each_range);