On Mon, Aug 11, 2014 at 12:51:22PM -0700, Kees Cook wrote: > On Mon, Aug 11, 2014 at 7:11 AM, Guenter Roeck <li...@roeck-us.net> wrote: > > On 08/11/2014 04:48 AM, Oleg Nesterov wrote: > >> > >> On 08/10, Linus Torvalds wrote: > >>> > >>> > >>> So that should just be converted to assert_spin_is_locked(). > >> > >> > >> I still think that lockdep_assert_held() is better. Unlike > >> assert_spin_locked() it checks that this lock is held by us, and this > >> is what we want in this case. > >> > > > > assert_spin_locked maps to "BUG_ON(!raw_spin_is_locked(x))" > > which it seems is exactly what the current code is doing. > > I submitted a patch to make that change to use assert_spin_locked. > > Presumably the author had a reason for using BUG_ON and not > > lockdep_assert_held(), ie to perform the checks all the time > > and not just while debugging. For me this was the safe change > > to make. Anything else should, in my opinion, come from the > > original author who introduced the code. > > Thanks for the patch! Yeah, that's a weird case; I think we need some > documentation in the header file about the UP vs SMP logic when using > spin_is_locked(). I note that all other stuff gets hidden behind the > _up and _smp headers. > Guess one has to know what to look for.
Documentation/scsi/ChangeLog.megaraid gives a hint, as do the comments next to WARN_ON_SMP. Not that I knew before last night :-). > I don't prefer lockdep_assert_held(), though, since I want lock > failures to hit BUG. I'll apply the patch and ask James to pull it. > Thanks a lot! Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
