From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Mark Brown Subject: [PATCH 4.4 002/210] regulator: core: avoid unused variable warning Date: Sun, 10 Apr 2016 11:33:43 -0700 Message-Id: <20160410183526.740642505@linuxfoundation.org> In-Reply-To: <20160410183526.651820045@linuxfoundation.org> References: <20160410183526.651820045@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit fa731ac7ea04a7d3a5c6d2f568132478c02a83b3 upstream. The second argument of the mutex_lock_nested() helper is only evaluated if CONFIG_DEBUG_LOCK_ALLOC is set. Otherwise we get this build warning for the new regulator_lock_supply function: drivers/regulator/core.c: In function 'regulator_lock_supply': drivers/regulator/core.c:142:6: warning: unused variable 'i' [-Wunused-variable] To avoid the warning, this restructures the code to make it both simpler and to move the 'i++' outside of the mutex_lock_nested call, where it is now always used and the variable is not flagged as unused. We had some discussion about changing mutex_lock_nested to an inline function, which would make the code do the right thing here, but in the end decided against it, in order to guarantee that mutex_lock_nested() does not introduced overhead without CONFIG_DEBUG_LOCK_ALLOC. Signed-off-by: Arnd Bergmann Fixes: 9f01cd4a915 ("regulator: core: introduce function to lock regulators and its supplies") Link: http://permalink.gmane.org/gmane.linux.kernel/2068900 Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/regulator/core.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -138,18 +138,10 @@ static bool have_full_constraints(void) */ static void regulator_lock_supply(struct regulator_dev *rdev) { - struct regulator *supply; - int i = 0; + int i; - while (1) { - mutex_lock_nested(&rdev->mutex, i++); - supply = rdev->supply; - - if (!rdev->supply) - return; - - rdev = supply->rdev; - } + for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++) + mutex_lock_nested(&rdev->mutex, i); } /**