Date: Wed, 06 Jun 2012 09:03:08 -0700 (PDT)
Message-Id: <20120606.090308.608629832776499558.davem@davemloft.net>
To: benh@kernel.crashing.org
Cc: R65777@freescale.com, aarcange@redhat.com, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, galak@kernel.crashing.org,
        linux-mm@kvack.org
Subject: Re: [PATCH] powerpc: Fix assmption of end_of_DRAM() returns end
 address
From: David Miller <davem@davemloft.net>
In-Reply-To: <1338960617.7150.163.camel@pasglop>
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	<1338960617.7150.163.camel@pasglop>
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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Wed, 06 Jun 2012 15:30:17 +1000

> On Wed, 2012-06-06 at 00:46 +0000, Bhushan Bharat-R65777 wrote:
> 
>> > >> memblock_end_of_DRAM() returns end_address + 1, not end address.
>> > >> While some code assumes that it returns end address.
>> > >
>> > > Shouldn't we instead fix it the other way around ? IE, make
>> > > memblock_end_of_DRAM() does what the name implies, which is to
>> return
>> > > the last byte of DRAM, and fix the -other- callers not to make bad
>> > > assumptions ?
>> > 
>> > That was my impression too when I saw this patch.
>> 
>> Initially I also intended to do so. I initiated a email on linux-mm@
>> subject "memblock_end_of_DRAM()  return end address + 1" and the only
>> response I received from Andrea was:
>> 
>> "
>> It's normal that "end" means "first byte offset out of the range". End
>> = not ok.
>> end = start+size.
>> This is true for vm_end too. So it's better to keep it that way.
>> My suggestion is to just fix point 1 below and audit the rest :)
>> "
> 
> Oh well, I don't care enough to fight this battle in my current state so
> unless Dave has more stamina than I have today, I'm ok with the patch.

I'm definitely without the samina to fight something like this right now :)
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