Messages in this thread | | | From | Chuhong Yuan <> | Date | Mon, 12 Aug 2019 20:51:25 +0800 | Subject | Re: [PATCH] regulator: core: Add devres versions of regulator_enable/disable |
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On Mon, Aug 12, 2019 at 7:07 PM Mark Brown <broonie@kernel.org> wrote: > > On Sat, Aug 10, 2019 at 09:44:45AM +0800, Chuhong Yuan wrote: > > On Fri, Aug 9, 2019 at 11:11 PM Mark Brown <broonie@kernel.org> wrote: > > > > I'm not super keen on managed versions of these functions since they're > > > very likely to cause reference counting issues between the probe/remove > > > path and the suspend/resume path which aren't obvious from the code, I'm > > > especially worried about double frees on release. > > > I find that 29 of 31 cases I found call regulator_disable() only when encounter > > probe failure or in .remove. > > So I think the devm versions of regulator_enable/disable() will not cause big > > problems. > > There's way more drivers using regulators than that... >
I wrote a new coccinelle script to detect all regulator_disable() in .remove, 101 drivers are found in total. Within them, 25 drivers cannot benefit from devres version of regulator_enable() since they have additional non-devm operations after regulator_disable() in .remove. Within the left 76 cases, 60 drivers (79%) only use regulator_disable() when encounter probe failure or in .remove. The left 16 cases mostly use regulator_disable() in _suspend(). Furthermore, 3 cases of 76 are found to forget to disable regulator when fail in probe. So I think a devres version of regulator_enable/disable() has more benefits than potential risk.
> > I even found a driver to forget to disable regulator when encounter > > probe failure, > > which is drivers/iio/adc/ti-adc128s052.c. > > And a devm version of regulator_enable() can prevent such mistakes. > > Yes, it's useful for that.
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