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From:   Bjorn Helgaas <bhelgaas@google.com>
Date:   Fri, 25 Jan 2019 15:19:58 -0600
Message-ID: <CAErSpo5pAQs-SJRKc-ie15zpSqf9FsPWnHeSpggU-EeZDg=AYQ@mail.gmail.com>
Subject: Re: [PATCH 1/5] mm/resource: return real error codes from walk failures
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     Dave Hansen <dave.hansen@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Jiang <dave.jiang@intel.com>, zwisler@kernel.org,
        vishal.l.verma@intel.com, thomas.lendacky@amd.com,
        Andrew Morton <akpm@linux-foundation.org>, mhocko@suse.com,
        linux-nvdimm@lists.01.org, linux-mm@kvack.org,
        Huang Ying <ying.huang@intel.com>,
        Wu Fengguang <fengguang.wu@intel.com>,
        Borislav Petkov <bp@suse.de>, baiyaowei@cmss.chinamobile.com,
        Takashi Iwai <tiwai@suse.de>,
        Jerome Glisse <jglisse@redhat.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
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On Fri, Jan 25, 2019 at 3:10 PM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 1/25/19 1:02 PM, Bjorn Helgaas wrote:
> >> @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long
> >>         unsigned long flags;
> >>         struct resource res;
> >>         unsigned long pfn, end_pfn;
> >> -       int ret = -1;
> >> +       int ret = -EINVAL;
> > Can you either make a similar change to the powerpc version of
> > walk_system_ram_range() in arch/powerpc/mm/mem.c or explain why it's
> > not needed?  It *seems* like we'd want both versions of
> > walk_system_ram_range() to behave similarly in this respect.
>
> Sure.  A quick grep shows powerpc being the only other implementation.
> I'll just add this hunk:
>
> > diff -puN arch/powerpc/mm/mem.c~memory-hotplug-walk_system_ram_range-returns-neg-1 arch/powerpc/mm/mem.c
> > --- a/arch/powerpc/mm/mem.c~memory-hotplug-walk_system_ram_range-returns-neg-1  2019-01-25 12:57:00.000004446 -0800
> > +++ b/arch/powerpc/mm/mem.c     2019-01-25 12:58:13.215004263 -0800
> > @@ -188,7 +188,7 @@ walk_system_ram_range(unsigned long star
> >         struct memblock_region *reg;
> >         unsigned long end_pfn = start_pfn + nr_pages;
> >         unsigned long tstart, tend;
> > -       int ret = -1;
> > +       int ret = -EINVAL;
>
> I'll also dust off the ol' cross-compiler and make sure I didn't
> fat-finger anything.

Sounds good.  Then add my

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>