On Wed, Feb 04, 2026 at 03:28:46PM +0100, Johan Hovold wrote: > I was surprised to learn that the revocable functionality was merged the other > week given the community feedback on list and at LPC, but not least since > there > are no users of it, which we are supposed to require to be able to evaluate it > properly. > > The chromeos ec driver issue which motivated this work turned out not to need > it as was found during review. And the example gpiolib conversion was posted > the very same morning that this was merged which hardly provides enough time > for evaluation (even if Bartosz quickly reported a performance regression). > > Turns out there are correctness issues with both the gpiolib conversion and > the revocable design itself that can lead to use-after-free and hung tasks > (see > [1] and [2]). > > And as was pointed out repeatedly during review, and again at the day of the > merge, this does not look like the right interface for the chardev unplug > issue. > > Despite the last-minute attempt at addressing the issues mentioned above > incrementally, the revocable design is still fundamentally flawed (see patch > 3/3). > > We have processes like requiring a user before merging a new interface so that > issues like these can be identified and the soundness of an API be evaluated. > They also give a sense of when things are expected to happen, which allows our > scarce reviewers to manage their time (e.g. to not be forced to drop > everything > else they are doing when things are merged prematurely). > > There really is no reason to exempt any new interface from this regardless of > whether one likes the underlying concept or not. > > Revert the revocable implementation until a redesign has been proposed and > evaluated properly.
After thinking about this a lot, and talking it over with Danilo a bit, I've applied this series that reverts these changes. Kernel developers / maintainers are only "allowed" one major argument / fight a year, and I really don't want to burn my 2026 usage so early in the year :) Tzung-Bi, can you take the feedback here, and what you have learned from the gpio patch series, and rework this into a "clean" patch series for us to review and comment on for future releases? That should give us all a baseline on which to work off of, without having to worry about the different versions/fixes floating around at the moment. thanks, greg k-h
