Skip to content

Commit

Permalink
regulator: core: avoid unused variable warning
Browse files Browse the repository at this point in the history
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: 9f01cd4 ("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>
  • Loading branch information
Arnd Bergmann authored and Mark Brown committed Nov 20, 2015
1 parent 8005c49 commit fa731ac
Showing 1 changed file with 3 additions and 11 deletions.
14 changes: 3 additions & 11 deletions drivers/regulator/core.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}

/**
Expand Down

0 comments on commit fa731ac

Please sign in to comment.