diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 7e6e84cf6383..6eb06101089f 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -435,6 +435,14 @@ struct compress_alg {
  * @cra_exit: Deinitialize the cryptographic transformation object. This is a
  *	      counterpart to @cra_init, used to remove various changes set in
  *	      @cra_init.
+ * @cra_u.ablkcipher: Union member which contains an asynchronous block cipher
+ *		      definition. See @struct @ablkcipher_alg.
+ * @cra_u.blkcipher: Union member which contains a synchronous block cipher
+ * 		     definition See @struct @blkcipher_alg.
+ * @cra_u.cipher: Union member which contains a single-block symmetric cipher
+ *		  definition. See @struct @cipher_alg.
+ * @cra_u.compress: Union member which contains a (de)compression algorithm.
+ *		    See @struct @compress_alg.
  * @cra_module: Owner of this transformation implementation. Set to THIS_MODULE
  * @cra_list: internally used
  * @cra_users: internally used