Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.
Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: netdev@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
 
                /* Check permissions */
                if (((tun->owner != -1 &&
-                     current->euid != tun->owner) ||
+                     current_euid() != tun->owner) ||
                     (tun->group != -1 &&
-                     current->egid != tun->group)) &&
+                     current_egid() != tun->group)) &&
                     !capable(CAP_NET_ADMIN))
                        return -EPERM;
        }