Re: [RFC/PATCH] init/main.c: Simplify initcall_blacklisted()

[Oleg Nesterov <oleg@redhat.com>]

On 01/20, Prarit Bhargava wrote:
>
> On 01/19/2015 08:05 PM, Rusty Russell wrote:
> > Oleg Nesterov <oleg@redhat.com> writes:
> >>
> >> If we want to optimize this... I am wondering if we can change
> >> initcall_blacklist()
> >>
> >> 	-	entry->buf = alloc_bootmem(strlen(str_entry) + 1);
> >> 	+	ebtry->fn = kallsyms_lookup_name(str_entry);
> >>
> >> and then change initcall_blacklisted() to just compare the pointers.
> >
> > That would make far, far more sense.  It would fail for modules of
> > course, but that might be OK.  Prarit, this was your code; does it
> > matter?
>
> It does actually matter to me.  I've been using it to blacklist modules at boot
> as well ... and it works really well :)  So I'm okay with the original patch but
> not the second suggested change.

Yes, I didn't know/realize that initcall_blacklist paramater can be
also used to disable the modules, thanks for correcting me.

But I'd say that initcall_blacklisted(mod->init) looks a bit strange,
I mean it would be probably better to use mod->name in this case, not
the "internal" name of this likely static function.

Perhaps even another kernel parameter makes sense for this, I dunno..
>From Documentation/kernel-parameters.txt:

	initcall_blacklist=  [KNL] Do not execute a comma-separated list of
			initcall functions.  Useful for debugging built-in
			modules and initcalls.

note that this only mentions built-in modules.

Nevermind, I was wrong anyway. Thanks!

Oleg.