linux-kernel - [PATCH 06/11] rcu: clear t->rcu_read_unlock

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Message-Id: <20191031100806.1326-7-laijs@linux.alibaba.com>
Date:   Thu, 31 Oct 2019 10:08:01 +0000
From:   Lai Jiangshan <laijs@...ux.alibaba.com>
To:     linux-kernel@...r.kernel.org
Cc:     Lai Jiangshan <laijs@...ux.alibaba.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Josh Triplett <josh@...htriplett.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Joel Fernandes <joel@...lfernandes.org>, rcu@...r.kernel.org
Subject: [PATCH 06/11] rcu: clear t->rcu_read_unlock_special in one go

Clearing t->rcu_read_unlock_special in one go makes the code
more clearly.

Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
---
 kernel/rcu/tree_plugin.h | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index bb3bcdb5c9b8..e612c77dc446 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -420,6 +420,7 @@ static bool rcu_preempt_has_tasks(struct rcu_node *rnp)
  * Report deferred quiescent states.  The deferral time can
  * be quite short, for example, in the case of the call from
  * rcu_read_unlock_special().
+ * t->rcu_read_unlock_special is cleared after called.
  */
 static void
 rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
@@ -439,11 +440,9 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
 	 * t->rcu_read_unlock_special cannot change.
 	 */
 	special = t->rcu_read_unlock_special;
-	t->rcu_read_unlock_special.b.exp_hint = false;
-	t->rcu_read_unlock_special.b.deferred_qs = false;
+	t->rcu_read_unlock_special.s = 0;
 	if (special.b.need_qs) {
 		rcu_qs();
-		t->rcu_read_unlock_special.b.need_qs = false;
 	}
 
 	/*
@@ -459,8 +458,6 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
 
 	/* Clean up if blocked during RCU read-side critical section. */
 	if (special.b.blocked) {
-		t->rcu_read_unlock_special.b.blocked = false;
-
 		/*
 		 * Remove this task from the list it blocked on.  The task
 		 * now remains queued on the rcu_node corresponding to the
-- 
2.20.1