net: Comment copy_from_sockptr() explaining its behaviour

copy_from_sockptr() has a history of misuse. Add a comment explaining that
the function follows API of copy_from_user(), i.e. returns 0 for success,
or number of bytes not copied on error.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/linux/sockptr.h b/include/linux/sockptr.h
index 195debe2b1dbc5abf768aa806eb6c73b99421e27..3e6c8e9d67aef66e8ac5a4e474c278ac08244163 100644 (file)
--- a/include/linux/sockptr.h
+++ b/include/linux/sockptr.h
@@ -53,6 +53,8 @@ static inline int copy_from_sockptr_offset(void *dst, sockptr_t src,
 /* Deprecated.
  * This is unsafe, unless caller checked user provided optlen.
  * Prefer copy_safe_from_sockptr() instead.
+ *
+ * Returns 0 for success, or number of bytes not copied on error.
  */
 static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size)
 {