On Thu 2024-07-25 16:19:30, Miroslav Benes wrote:
> On Fri, 10 Nov 2023, Josh Poimboeuf wrote:
>
> > On Fri, Nov 10, 2023 at 06:04:21PM +0100, Petr Mladek wrote:
> > > This POC is a material for the discussion "Simplify Livepatch Callbacks,
> > > Shadow Variables, and States handling" at LPC 2013, see
> > > https://lpc.events/event/17/contributions/1541/
> > >
> > > It obsoletes the patchset adding the garbage collection of shadow
> > > variables. This new solution is based on ideas from Nicolai Stange.
> > > And it should also be in sync with Josh's ideas mentioned into
> > > the thread about the garbage collection, see
> > > https://lore.kernel.org/r/20230204235910.4j4ame5ntqogqi7m@treble
> >
> > Nice! I like how it brings the "features" together and makes them easy
> > to use. This looks like a vast improvement.
> >
> > Was there a reason to change the naming? I'm thinking
> >
> > setup / enable / disable / release
> >
> > is less precise than
> >
> > pre_patch / post_patch / pre_unpatch / post_unpatch.
I wanted to point out that the callbacks are called _only_ when
the states are added or removed. They are not called when the state
is preserved during the atomic replace.
The pre_patch... naming scheme might create an assumption that they
are _always_ called during the livepatch transition.
But I see that the new names might be misleading in other ways.
I am going to use the "pre_patch..." names in the next version of
the patchset.
> > Also, I'm thinking "replaced" instead of "obsolete" would be more
> > consistent with the existing terminology.
> >
> > For example, in __klp_enable_patch():
> >
> > ret = klp_setup_states(patch);
> > if (ret)
> > goto err;
> >
> > if (patch->replace)
> > klp_disable_obsolete_states(patch);
> >
> > it's not immediately clear why "disable obsolete" would be the "replace"
> > counterpart to "setup".
> >
> > Similarly, in klp_complete_transition():
> >
> > if (klp_transition_patch->replace && klp_target_state == KLP_PATCHED) {
> > klp_unpatch_replaced_patches(klp_transition_patch);
> > klp_discard_nops(klp_transition_patch);
> > klp_release_obsolete_states(klp_transition_patch);
> > }
> >
> > it's a little jarring to have "unpatch replaced" followed by "release
> > obsolete".
I see.
> I agree. I would also stick to the existing naming. It is clearer to me.
Fair enough.
Best Regards,
Petr
