CRED: Wrap current->cred and a few other accessors

Wrap current->cred and a few other accessors to hide their actual
implementation.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index b6dd4fc..247cec3 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -164,7 +164,7 @@
 {
 	int rc;
 
-	rc = smk_access(current->cred->security, obj_label, mode);
+	rc = smk_access(current_security(), obj_label, mode);
 	if (rc == 0)
 		return 0;