In-Reply-To: <20080826165536.61c25a67.akpm@linux-foundation.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Bruce Leonard <brucle@earthlink.net>,
       David Woodhouse <dwmw2@infradead.org>, linux-kernel@vger.kernel.org,
       linux-mtd@lists.infradead.org, linux-mtd-bounces@lists.infradead.org
Subject: Re: [PATCH 2/2][MTD] Add support for > 2GiB MTD devices
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Message-ID: <OF7C027ED9.D9F1F324-ON882574B2.0007025B-882574B2.000767B6@selinc.com>
From: Bruce_Leonard@selinc.com
Date: Tue, 26 Aug 2008 18:21:03 -0700
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linux-mtd-bounces@lists.infradead.org wrote on 08/26/2008 04:55:36 PM:

> On Thu, 21 Aug 2008 19:00:55 -0700 (GMT-07:00)
> Bruce Leonard <brucle@earthlink.net> wrote:
> 
> > --- a/include/mtd/mtd-abi.h
> > +++ b/include/mtd/mtd-abi.h
> > @@ -6,7 +6,7 @@
> >  #define __MTD_ABI_H__
> > 
> >  struct erase_info_user {
> > -   uint32_t start;
> > +   uint64_t start;
> >     uint32_t length;
> >  };
> > 
> > @@ -50,7 +50,7 @@ struct mtd_oob_buf {
> >  struct mtd_info_user {
> >     uint8_t type;
> >     uint32_t flags;
> > -   uint32_t size;    // Total size of the MTD
> > +   uint64_t size;    // Total size of the MTD
> >     uint32_t erasesize;
> >     uint32_t writesize;
> >     uint32_t oobsize;   // Amount of OOB data per block (e.g. 16)
> 
> This changes the kernel<->userspace ABI and is hence a big no-no.  I
> assume that this change will cause old userspace to malfunction on new
> kernels, and vice versa.
> 

Well, in my posting I noted that the mtd-utils were broken because of this 
but I didn't really have any idea as to how to fix things.  I can see why 
it would be a big no-no to change this.  Do you have any suggestions on 
what I could do differently to prevent making that change?

> Supporting >2Gb MTD devices sounds useful (I'm surprised that we don't
> already do so).
> 

There was a LOT of interest in this over the last few months while I was 
working on it, but a very suprising silence has developed since I posted 
the patches.  I guess I'm more cutting edge than I thought :).

> Please cc linux-mtd@lists.infradead.org (at least) on MTD-related
> patches, thanks.

I started with the MTD list and then also posted to lkml when I realized I 
had forgotten to CC it.

Thanks.

Bruce
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