Messages in this thread | | | From | Chuhong Yuan <> | Date | Mon, 12 Aug 2019 22:19:33 +0800 | Subject | Re: [PATCH] regulator: core: Add devres versions of regulator_enable/disable |
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On Mon, Aug 12, 2019 at 8:51 PM Chuhong Yuan <hslester96@gmail.com> wrote: > > 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.
I find 6 of 25 can benefit from devm_regulator_enable(). They are included in my previously found 147 cases so I incorrectly skipped them while checking. Therefore, there are 82 cases that can benefit from devm_regulator_enable() and 66 of them(80.5%) only call regulator_disable() when fail in probe or 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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