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/exit.c b/kernel/exit.c
index 80137a5..e0f6e18 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -160,7 +160,7 @@
 	int zap_leader;
 repeat:
 	tracehook_prepare_release_task(p);
-	atomic_dec(&p->user->processes);
+	atomic_dec(&p->cred->user->processes);
 	proc_flush_task(p);
 	write_lock_irq(&tasklist_lock);
 	tracehook_finish_release_task(p);
@@ -1272,7 +1272,7 @@
 		return 0;
 
 	if (unlikely(options & WNOWAIT)) {
-		uid_t uid = p->uid;
+		uid_t uid = p->cred->uid;
 		int exit_code = p->exit_code;
 		int why, status;
 
@@ -1393,7 +1393,7 @@
 	if (!retval && infop)
 		retval = put_user(pid, &infop->si_pid);
 	if (!retval && infop)
-		retval = put_user(p->uid, &infop->si_uid);
+		retval = put_user(p->cred->uid, &infop->si_uid);
 	if (!retval)
 		retval = pid;
 
@@ -1458,7 +1458,7 @@
 	if (!unlikely(options & WNOWAIT))
 		p->exit_code = 0;
 
-	uid = p->uid;
+	uid = p->cred->uid;
 unlock_sig:
 	spin_unlock_irq(&p->sighand->siglock);
 	if (!exit_code)
@@ -1535,7 +1535,7 @@
 	spin_unlock_irq(&p->sighand->siglock);
 
 	pid = task_pid_vnr(p);
-	uid = p->uid;
+	uid = p->cred->uid;
 	get_task_struct(p);
 	read_unlock(&tasklist_lock);