On 15-06-12 02:49 AM, Thierry Reding wrote:
> On Tue, May 26, 2015 at 01:08:20PM -0700, Jonathan Richardson wrote:
>> The pwm_enable function didn't clear the enabled bit if a call to a
>> clients enable function returned an error. The result was that the state
>> of the pwm core was wrong. Clearing the bit when enable returns an error
>> ensures the state is properly set.
>>
>> Tested-by: Jonathan Richardson <jonat...@broadcom.com>
>> Reviewed-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
>> Signed-off-by: Jonathan Richardson <jonat...@broadcom.com>
>> ---
>> drivers/pwm/core.c | 16 +++++++++++++---
>> 1 file changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
>> index 224645f..18f5ac4 100644
>> --- a/drivers/pwm/core.c
>> +++ b/drivers/pwm/core.c
>> @@ -477,10 +477,20 @@ EXPORT_SYMBOL_GPL(pwm_set_polarity);
>> */
>> int pwm_enable(struct pwm_device *pwm)
>> {
>> - if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
>> - return pwm->chip->ops->enable(pwm->chip, pwm);
>> + int err;
>> +
>> + if (!pwm)
>> + return -EINVAL;
>> +
>> + if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
>> + err = pwm->chip->ops->enable(pwm->chip, pwm);
>> + if (err) {
>> + clear_bit(PWMF_ENABLED, &pwm->flags);
>> + return err;
>> + }
>> + }
>
> I think with this new pattern we're now actually going to need a lock to
> make sure pwm->flags doesn't change between the test_and_set_bit() and
> clear_bit() calls.
>
> Thierry
>
Ok. I'll add a lock per pwm_device and re-send the patch.
Jon
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
