CRED: Documentation
Document credentials and the new credentials API.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 8edb4d1..794aab5 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -1,4 +1,4 @@
-/* Credentials management
+/* Credentials management - see Documentation/credentials.txt
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
@@ -169,6 +169,12 @@
*
* Get a reference on the specified set of credentials. The caller must
* release the reference.
+ *
+ * This is used to deal with a committed set of credentials. Although the
+ * pointer is const, this will temporarily discard the const and increment the
+ * usage count. The purpose of this is to attempt to catch at compile time the
+ * accidental alteration of a set of credentials that should be considered
+ * immutable.
*/
static inline const struct cred *get_cred(const struct cred *cred)
{
@@ -181,6 +187,10 @@
*
* Release a reference to a set of credentials, deleting them when the last ref
* is released.
+ *
+ * This takes a const pointer to a set of credentials because the credentials
+ * on task_struct are attached by const pointers to prevent accidental
+ * alteration of otherwise immutable credential sets.
*/
static inline void put_cred(const struct cred *_cred)
{