2016-09-15 16:38 GMT+02:00 Peter Zijlstra <pet...@infradead.org>: > On Thu, Sep 15, 2016 at 04:08:52PM +0200, Bartosz Golaszewski wrote: >> 2016-09-15 15:39 GMT+02:00 Peter Zijlstra <pet...@infradead.org>: > >> > In any case, if this fails, we can always punt and simply count the >> > total number of instances of this driver on the system and go with that. >> > >> >> But for __mutex_init() to work with the key argument you need to know >> it at compile time, right? > > You can do something like: > > mutex_init(&mutex); > lockdep_set_subclass(&mutex, nr); > > which will of course fail at runtime the moment nr >= 8, but is that > really a concern? > > Equally you can do: > > static struct lock_class_key my_keys[NR]; > > mutex_init(&mutex); > BUG_ON(nr > NR); > lockdep_set_class(&mutex, my_keys + nr); > > and have a bigger limit.
Thanks, I was not aware of this API. Best regards, Bartosz Golaszewski
