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/fs/exec.c b/fs/exec.c
index 604834f..31149e4 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1738,7 +1738,7 @@
 	 */
 	if (get_dumpable(mm) == 2) {	/* Setuid core dump mode */
 		flag = O_EXCL;		/* Stop rewrite attacks */
-		current->fsuid = 0;	/* Dump root private */
+		current->cred->fsuid = 0;	/* Dump root private */
 	}
 
 	retval = coredump_wait(exit_code, &core_state);
@@ -1834,7 +1834,7 @@
 	if (helper_argv)
 		argv_free(helper_argv);
 
-	current->fsuid = fsuid;
+	current->cred->fsuid = fsuid;
 	coredump_finish(mm);
 fail:
 	return retval;