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regulator: core: avoid unused variable warning

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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 <arnd@arndb.de>
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 <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Arnd Bergmann 2015-11-20 15:24:39 +01:00 committed by Greg Kroah-Hartman
parent 84cf91ad33
commit 4c8fe4f527
1 changed files with 3 additions and 11 deletions
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14
drivers/regulator/core.c
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@ -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);
}
/**