Hello, On Thu, Apr 12, 2018 at 06:56:26PM +0000, Bart Van Assche wrote: > On Thu, 2018-04-12 at 11:11 -0700, t...@kernel.org wrote: > > * Right now, blk_queue_enter/exit() doesn't have any annotations. > > IOW, there's no way for paths which need enter locked to actually > > assert that. If we're gonna protect more things with queue > > enter/exit, it gotta be annotated. > > Hello Tejun, > > One possibility is to check the count for the local CPU of q->q_usage_counter > at runtime, e.g. using WARN_ON_ONCE(). However, that might have a runtime > overhead. Another possibility is to follow the example of kernfs and to use > a lockdep map and lockdep_assert_held(). There might be other alternatives I > have not thought of.
Oh, I'd just do straight-forward lockdep annotation on queue_enter/exit functions and provide the necessary assert helpers. Thanks. -- tejun