linux-kernel - [PATCH 1/3] regulator: don't require mutex for regulator_notifier_call

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Message-Id: <5a0da9017c69a4dbc3f9b50f44476fce80a73387.1597032945.git.mirq-linux@rere.qmqm.pl>
Date:   Mon, 10 Aug 2020 06:33:32 +0200
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Dmitry Osipenko <digetx@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Support Opensource <support.opensource@...semi.com>
Cc:     linux-kernel@...r.kernel.org, patches@...nsource.cirrus.com
Subject: [PATCH 1/3] regulator: don't require mutex for
 regulator_notifier_call_chain()

Since 3801b86aa482 ("regulator: Refactor supply implementation
to work as regular consumers") we no longer cascade notifications
and so notifier head's built-in rwsem is enough to protect the
notifier chain. Remove the requirement to fix one case where
rdev->mutex might be forced to be taken recursively.

Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
 drivers/regulator/core.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index b0662927487c..f4035167e7ba 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -4658,14 +4658,11 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
  * @data: callback-specific data.
  *
  * Called by regulator drivers to notify clients a regulator event has
- * occurred. We also notify regulator clients downstream.
- * Note lock must be held by caller.
+ * occurred.
  */
 int regulator_notifier_call_chain(struct regulator_dev *rdev,
 				  unsigned long event, void *data)
 {
-	lockdep_assert_held_once(&rdev->mutex.base);
-
 	_notifier_call_chain(rdev, event, data);
 	return NOTIFY_DONE;
 
-- 
2.20.1