On Tue, 24 Jun 2025 at 22:04, Sasha Levin <sas...@kernel.org> wrote: > >9. I see that syscalls and ioctls say: > >KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE) > >Can't we make this implicit? Are there any other options? > > Maybe? I wasn't sure how we'd describe somthing like getpid() which > isn't supposed to sleep. > > >Similarly an ioctl description says it releases a mutex (.released = true,), > >all ioctls/syscalls must release all acquired mutexes, no? > >Generally, the less verbose the descriptions are, the higher chances of > >their survival. > >+Marco also works static compiler-enforced lock checking annotations, > >I wonder if they can be used to describe this in a more useful way. > > I was thinking about stuff like futex or flock which can return with a > lock back to userspace.
I see, this makes sense. Then I would go with explicitly specifying rare uncommon cases instead, and require 99% of common cases be the default that does not require saying anything. E.g. KAPI_CTX_NON_SLEEPABLE, .not_released = true. KAPI_CTX_NON_SLEEPABLE looks useful, since it allows easy validation: set current flag, and BUG on any attempt to sleep when the flag is set (lockdep probably already has required pieces for this).
