Commit fa731ac7 authored Nov 20, 2015 by Arnd Bergmann Committed by Mark Brown Nov 20, 2015

regulator: core: avoid unused variable warning



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 <arnd@arndb.de>
Fixes: 9f01cd4a ("regulator: core: introduce function to lock regulators and its supplies")
Link: http://permalink.gmane.org/gmane.linux.kernel/2068900


Signed-off-by: Mark Brown <broonie@kernel.org>

parent 8005c49d

drivers/regulator/core.c

+3 −11

Original line number	Diff line number	Diff line
		@@ -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;

		while (1) {
		mutex_lock_nested(&rdev->mutex, i++);
		supply = rdev->supply;

		if (!rdev->supply)
		return;
		int i;

		rdev = supply->rdev;
		}
		for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++)
		mutex_lock_nested(&rdev->mutex, i);
		}

		/**

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