On Mon, Aug 31, 2015 at 08:53:11AM +0000, ???? / KAWAI?HIDEHIRO wrote:
> > I understand your question. I don't intend to permit the recursive
> > call of crash_kexec() as for 'old_cpu != this_cpu' check. That is
> > needed for the case of panic() --> crash_kexec(). Since panic_cpu has
> > already been set to this_cpu in panic() (please see PATCH 1/4), no one
> > can run crash_kexec() without 'old_cpu != this_cpu' check.
> >
> > If you don't like this check, I would also be able to handle this case
> > like below:
> >
> > crash_kexec()
> > {
> > old_cpu = atomic_cmpxchg(&panic_cpu, -1, this_cpu);
> > if (old_cpu != -1)
> > return;
> >
> > __crash_kexec();
> > }
> >
> > panic()
> > {
> > atomic_cmpxchg(&panic_cpu, -1, this_cpu);
> > __crash_kexec();
> > ...
> >
>
> Is that OK?
I suppose so, but I think me getting confused means comments can be
added/improved.
