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Date:   Tue, 3 Jul 2018 18:47:51 +0300
From:   Mike Rapoport <rppt@linux.vnet.ibm.com>
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Greg Ungerer <gerg@linux-m68k.org>,
        Sam Creasey <sammy@sammy.net>, linux-m68k@lists.linux-m68k.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] m68k/page_no.h: force __va argument to be unsigned
 long
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On Tue, Jul 03, 2018 at 05:14:01PM +0200, Michal Hocko wrote:
> On Tue 03-07-18 08:05:35, Matthew Wilcox wrote:
> > On Tue, Jul 03, 2018 at 06:03:16PM +0300, Mike Rapoport wrote:
> > > On Tue, Jul 03, 2018 at 04:20:54PM +0200, Michal Hocko wrote:
> > > > On Tue 03-07-18 13:29:54, Mike Rapoport wrote:
> > > > > Add explicit casting to unsigned long to the __va() parameter
> > > > 
> > > > Why is this needed?
> > > 
> > > To make it consitent with other architecures and asm-generic :)
> > > 
> > > But more importantly, __memblock_free_late() passes u64 to page_to_pfn().
> > 
> > Why does memblock work in terms of u64 instead of phys_addr_t?
> 
> Yes, phys_addr_t was exactly that came to my mind as well. Casting
> physical address to unsigned long just screams for potential problems.

Not sure if for m68k-nommu the physical address can really go beyond 32
bits, but in general this is something that should be taken care of.

I think adding the cast in m68k-nommu case is a viable band aid to allow
sorting out the bootmem vs nobootmem.

In any case care should be taken of all those

	#define __va(x)	((void *)((unsigned long)(x))) 

all around.

Regardless, I can s/u64/phys_addr_t/ in memblock.c.

> -- 
> Michal Hocko
> SUSE Labs
> 

-- 
Sincerely yours,
Mike.