From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758738AbbLBPyz (ORCPT ); Wed, 2 Dec 2015 10:54:55 -0500 Received: from mail-wm0-f54.google.com ([74.125.82.54]:36000 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753062AbbLBPyx (ORCPT ); Wed, 2 Dec 2015 10:54:53 -0500 From: Thierry Reding To: Mark Brown Cc: linux-kernel@vger.kernel.org, Arnd Bergmann Subject: [PATCH] regulator: core: Fix nested locking of supplies Date: Wed, 2 Dec 2015 16:54:50 +0100 Message-Id: <1449071690-1686-1-git-send-email-thierry.reding@gmail.com> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thierry Reding Commit fa731ac7ea04 ("regulator: core: avoid unused variable warning") introduced a subtle change in how supplies are locked. Where previously code was always locking the regulator of the current iteration, the new implementation only locks the regulator if it has a supply. For any given power tree that means that the root will never get locked. On the other hand the regulator_unlock_supply() will still release all the locks, which in turn causes the lock debugging code to warn about a mutex being unlocked which wasn't locked. Cc: Mark Brown Cc: Arnd Bergmann Fixes: Fixes: fa731ac7ea04 ("regulator: core: avoid unused variable warning") Signed-off-by: Thierry Reding --- drivers/regulator/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index c9bdca5f3b9b..6653b1b4ff0f 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -132,6 +132,14 @@ static bool have_full_constraints(void) return has_full_constraints || of_have_populated_dt(); } +static inline struct regulator_dev *rdev_get_supply(struct regulator_dev *rdev) +{ + if (rdev && rdev->supply) + return rdev->supply->rdev; + + return NULL; +} + /** * regulator_lock_supply - lock a regulator and its supplies * @rdev: regulator source @@ -140,7 +148,7 @@ static void regulator_lock_supply(struct regulator_dev *rdev) { int i; - for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++) + for (i = 0; rdev; rdev = rdev_get_supply(rdev), i++) mutex_lock_nested(&rdev->mutex, i); } -- 2.5.0