On Tue, 15 Oct 2019 12:50:59 +0200 (CEST)
Miroslav Benes <mbenes@xxxxxxx> wrote:
> > > > @@ -6752,12 +6764,19 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
> > > > ftrace_startup_sysctl();
> > > >
> > > > } else {
> > > > + if (is_permanent_ops_registered()) {
> > > > + ftrace_enabled = last_ftrace_enabled;
> > >
> > > Although this is not incorrect, but may be somewhat confusing.
> > >
> > > At this location, last_ftrace_enabled is always true.
> > >
> > > I'm thinking this would be better to simply set it to false here.
> >
> > IMHO, we want to set ftrace_enabled = true here.
Yes, I meant true (don't know why I said false :-/ )
> >
> > It was set to "false" by writing to the sysfs file. But the change
> > gets rejected. ftrace will stay enabled. So, we should set
> > the value back to "true".
>
> That's correct.
>
> I can make it explicit as proposed. I just thought that 'ftrace_enabled =
> last_ftrace_enabled' was clear enough given Petr's explanation.
>
> > > > + ret = -EBUSY;
> > > > + goto out;
> > > > + }
> > > > +
> > > > /* stopping ftrace calls (just send to ftrace_stub) */
> > > > ftrace_trace_function = ftrace_stub;
> > > >
> > > > ftrace_shutdown_sysctl();
> > > > }
> > > >
> > > > + last_ftrace_enabled = !!ftrace_enabled;
> > > > out:
> > >
> > > And move the assignment of last_ftrace_enabled to after the "out:"
> > > label.
> >
> > This change might make sense anyway. But it is not strictly necessary
> > from my POV.
>
> If it stays before "out:" label, last_ftrace_enabled is set if and only if
> it has to be set. I think it is better, but I can, of course, move it in
> v3 if Steven prefers it.
I don't have any strong feelings here. If you want to keep it like
this, I wont argue.
-- Steve
