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From:   "Joel Fernandes (Google)" <joel@joelfernandes.org>
To:     linux-kernel@vger.kernel.org
Cc:     "Joel Fernandes (Google)" <joel@joelfernandes.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Josh Triplett <josh@joshtriplett.org>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        linux-doc@vger.kernel.org,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        "Paul E. McKenney" <paulmck@linux.ibm.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>, rcu@vger.kernel.org,
        Steven Rostedt <rostedt@goodmis.org>, Tejun Heo <tj@kernel.org>
Subject: [PATCH 1/3] workqueue: Convert for_each_wq to use built-in list check (v2)
Date:   Sun, 11 Aug 2019 18:11:09 -0400
Message-Id: <20190811221111.99401-1-joel@joelfernandes.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

list_for_each_entry_rcu now has support to check for RCU reader sections
as well as lock. Just use the support in it, instead of explicitly
checking in the caller.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 kernel/workqueue.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 601d61150b65..e882477ebf6e 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -364,11 +364,6 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
 			 !lockdep_is_held(&wq_pool_mutex),		\
 			 "RCU or wq_pool_mutex should be held")
 
-#define assert_rcu_or_wq_mutex(wq)					\
-	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
-			 !lockdep_is_held(&wq->mutex),			\
-			 "RCU or wq->mutex should be held")
-
 #define assert_rcu_or_wq_mutex_or_pool_mutex(wq)			\
 	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
 			 !lockdep_is_held(&wq->mutex) &&		\
@@ -425,9 +420,8 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
  * ignored.
  */
 #define for_each_pwq(pwq, wq)						\
-	list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node)		\
-		if (({ assert_rcu_or_wq_mutex(wq); false; })) { }	\
-		else
+	list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,		\
+				 lock_is_held(&(wq->mutex).dep_map))
 
 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 
-- 
2.23.0.rc1.153.gdeed80330f-goog