Re: [PATCH 1/2] powerpc: drop dependency on <asm/machdep.h> in archrandom.h

From: Yury Norov <yury.norov@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	"open list:LINUX FOR POWERPC PA SEMI PWRFICIENT" 
	<linuxppc-dev@lists.ozlabs.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	"Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: [PATCH 1/2] powerpc: drop dependency on <asm/machdep.h> in archrandom.h
Date: Tue, 26 Jul 2022 08:19:09 -0700	[thread overview]
Message-ID: <YuAF7ahr58HjMqXs@yury-laptop> (raw)
In-Reply-To: <87edy8bbtp.fsf@mpe.ellerman.id.au>

On Tue, Jul 26, 2022 at 04:57:38PM +1000, Michael Ellerman wrote:
> Yury Norov <yury.norov@gmail.com> writes:
> > On Mon, Jul 25, 2022 at 09:28:12AM +0200, Andy Shevchenko wrote:
> >> On Sun, Jul 24, 2022 at 12:19 AM Yury Norov <yury.norov@gmail.com> wrote:
> >> >
> >> > archrandom.h includes <asm/machdep.h> to refer ppc_md. This causes
> >> > circular header dependency, if generic nodemask.h  includes random.h:
> >> >
> >> > In file included from include/linux/cred.h:16,
> >> >                  from include/linux/seq_file.h:13,
> >> >                  from arch/powerpc/include/asm/machdep.h:6,
> >> >                  from arch/powerpc/include/asm/archrandom.h:5,
> >> >                  from include/linux/random.h:109,
> >> >                  from include/linux/nodemask.h:97,
> >> >                  from include/linux/list_lru.h:12,
> >> >                  from include/linux/fs.h:13,
> >> >                  from include/linux/compat.h:17,
> >> >                  from arch/powerpc/kernel/asm-offsets.c:12:
> >> > include/linux/sched.h:1203:9: error: unknown type name 'nodemask_t'
> >> >  1203 |         nodemask_t                      mems_allowed;
> >> >       |         ^~~~~~~~~~
> >> >
> >> > Fix it by removing <asm/machdep.h> dependency from archrandom.h
> >> 
> >> ...
> >> 
> >> >  EXPORT_SYMBOL_GPL(pm_power_off);
> >> 
> >> ^^^ (Note this and read below)
> >> 
> >> ...
> >> 
> >> > +EXPORT_SYMBOL(arch_get_random_seed_long);
> >> 
> >> It can't be like this. Brief browsing of the callees shows that.
> >
> > Is my understanding correct that you're suggesting to make it GPL?
> >
> > ppc_md is exported with EXPORT_SYMBOL(), and the function is in header,
> > so it's available for non-GPL code now. I don't want to change it.
> 
> That's true, your change maintains the status quo.
> 
> But I think we actually don't need it exported to modules, I think it's
> a private detail of the RNG <-> architecture interface, not something
> that modules should be calling.
> 
> So I think it's OK to drop the EXPORT_SYMBOL, either in this patch or a
> subsequent one if you don't want to rebase.

OK, changed.