CRED: Separate task security context from task_struct

Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

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/kernel/user.c b/kernel/user.c
index 39d6159..104d22a 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -457,11 +457,11 @@
 	 * cheaply with the new uid cache, so if it matters
 	 * we should be checking for it.  -DaveM
 	 */
-	old_user = current->user;
+	old_user = current->cred->user;
 	atomic_inc(&new_user->processes);
 	atomic_dec(&old_user->processes);
 	switch_uid_keyring(new_user);
-	current->user = new_user;
+	current->cred->user = new_user;
 	sched_switch_user(current);
 
 	/*