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Date: Thu, 11 Oct 2018 09:08:50 +0300
From: Mike Rapoport <rppt@linux.vnet.ibm.com>
Subject: Re: [PATCH] memblock: stop using implicit alignement to
 SMP_CACHE_BYTES
References: <1538687224-17535-1-git-send-email-rppt@linux.vnet.ibm.com>
 <20181005151934.87226fa92825c3002a475413@linux-foundation.org>
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To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, Catalin Marinas <catalin.marinas@arm.com>, Chris Zankel <chris@zankel.net>, Geert Uytterhoeven <geert@linux-m68k.org>, Guan Xuetao <gxt@pku.edu.cn>, Ingo Molnar <mingo@redhat.com>, Matt Turner <mattst88@gmail.com>, Michael Ellerman <mpe@ellerman.id.au>, Michal Hocko <mhocko@suse.com>, Michal Simek <monstr@monstr.eu>, Paul Burton <paul.burton@mips.com>, Richard Weinberger <richard@nod.at>, Russell King <linux@armlinux.org.uk>, Thomas Gleixner <tglx@linutronix.de>, Tony Luck <tony.luck@intel.com>, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@vger.kernel.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-um@lists.infradead.org

On Fri, Oct 05, 2018 at 03:19:34PM -0700, Andrew Morton wrote:
> On Fri,  5 Oct 2018 00:07:04 +0300 Mike Rapoport <rppt@linux.vnet.ibm.com> wrote:
> 
> > When a memblock allocation APIs are called with align = 0, the alignment is
> > implicitly set to SMP_CACHE_BYTES.
> > 
> > Replace all such uses of memblock APIs with the 'align' parameter explicitly
> > set to SMP_CACHE_BYTES and stop implicit alignment assignment in the
> > memblock internal allocation functions.
> > 
> > For the case when memblock APIs are used via helper functions, e.g. like
> > iommu_arena_new_node() in Alpha, the helper functions were detected with
> > Coccinelle's help and then manually examined and updated where appropriate.
> > 
> > ...
> >
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -1298,9 +1298,6 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
> >  {
> >  	phys_addr_t found;
> >  
> > -	if (!align)
> > -		align = SMP_CACHE_BYTES;
> > -
> 
> Can we add a WARN_ON_ONCE(!align) here?  To catch unconverted code
> which sneaks in later on.

Here it goes: