From: Bob Liu <lliubbo@gmail.com>
To: "Daniel Glöckner" <daniel-gl@gmx.net>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org, gerg@snapgear.com,
dhowells@redhat.com, lethal@linux-sh.org, gerg@uclinux.org,
walken@google.com, uclinux-dist-devel@blackfin.uclinux.org,
geert@linux-m68k.org
Subject: Re: [PATCH] nommu: reimplement remap_pfn_range() to simply return 0
Date: Mon, 20 Jun 2011 15:51:15 +0800 [thread overview]
Message-ID: <BANLkTinEi9u7D9wm_KANNfZWQ=xVPBBHKg@mail.gmail.com> (raw)
In-Reply-To: <20110620065907.GA29075@minime.bse>
On Mon, Jun 20, 2011 at 2:59 PM, Daniel Glöckner <daniel-gl@gmx.net> wrote:
> On Mon, Jun 20, 2011 at 01:22:13PM +0800, Bob Liu wrote:
>> Function remap_pfn_range() means map physical address pfn<<PAGE_SHIFT to
>> user addr.
>>
>> For nommu arch it's implemented by vma->vm_start = pfn << PAGE_SHIFT which is
>> wrong acroding the original meaning of this function.
>>
>> Some driver developer using remap_pfn_range() with correct parameter will get
>> unexpected result because vm_start is changed.
>>
>> It should be implementd just like addr = pfn << PAGE_SHIFT which is meanless
>> on nommu arch, so this patch just make it simply return 0.
>
> I'd return -EINVAL if addr != pfn << PAGE_SHIFT.
okay.
> And I can imagine architectures wanting to do something with the prot flags.
>
Actually it's just a fake function on nommu arch, so in my opinion
we'd better keep it simple
as current.
--
Regards,
--Bob
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next prev parent reply other threads:[~2011-06-20 7:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-20 5:22 Bob Liu
2011-06-20 6:59 ` Daniel Glöckner
2011-06-20 7:51 ` Bob Liu [this message]
2011-06-20 12:04 ` [uclinux-dist-devel] " Mike Frysinger
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