rcu/nocb: Use separate flag to indicate disabled ->cblist

NULLing the RCU_NEXT_TAIL pointer was a clever way to save a byte, but
forward-progress considerations would require that this pointer be both
NULL and non-NULL, which, absent a quantum-computer port of the Linux
kernel, simply won't happen.  This commit therefore creates as separate
->enabled flag to replace the current NULL checks.

[ paulmck: Add include files per 0day test robot and -next. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 0a3f8680b450..b8a43cf9bb4e 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2189,8 +2189,8 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
 				rcu_segcblist_n_cbs(&rdp->cblist));
 		atomic_long_set(&rdp->nocb_q_count_lazy,
 				rcu_segcblist_n_lazy_cbs(&rdp->cblist));
-		rcu_segcblist_init(&rdp->cblist);
 	}
+	rcu_segcblist_init(&rdp->cblist);
 	rcu_segcblist_disable(&rdp->cblist);
 	return true;
 }