On Mon, Apr 01, 2019 at 01:54:14PM +0200, Wolfram Sang wrote: > > > > "This matches the use cases for atomic I2C transfers I have seen so far: > > > very late communication (mostly to a PMIC) to powerdown or reboot the > > > system." > > > > Ah, sorry, I missed that. > > > > > And yes, I would never recommend a HW design to use I2C for shutting > > > down/rebooting. But such HW is out there. > > > > Can we then make the whole thing conditional on: > > > > system_state > SYSTEM_RUNNING > > > > Such that we're sure to never trigger this under any other conditions? > > Oh, we can for sure modify the code to something else. Actually, this is > why I was calling out to you. I was never comfortable with the old > 'in_atomic() || irqs_disabled()' code, but wasn't sure what would be an > adequate replacement which will not risk regressions. > > The above condition makes much more sense to me and is also much more > readable. Can it simply replace irqs_disabled()? Are interrupts already > disabled for system_state > SYSTEM_RUNNING? (I got a bit lost in the > code paths when trying to figure it out) Looking at kernel_restart_prepare(), we set SYSTEM_REBOOT in normal context, specifically it just did a blocking notifier call. So no, you'll have to combine the two.
