Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH, once again] regulator: core: avoid unused variable warning | Date | Fri, 20 Nov 2015 12:30:24 +0100 |
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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 patch moves the postincrement outside of the call mutex_lock_nested(), which is enough to shut up gcc about it.
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 --- The patch that introduced the warning is now in 4.4-rc1, and I think this patch is still the least ugly workaround we found.
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 4cf1390784e5..cf5371ee0be4 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -142,7 +142,9 @@ static void regulator_lock_supply(struct regulator_dev *rdev) int i = 0; while (1) { - mutex_lock_nested(&rdev->mutex, i++); + mutex_lock_nested(&rdev->mutex, i); + i++; + supply = rdev->supply; if (!rdev->supply)
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