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SubjectRE: [PATCH 2/2][MTD] Add support for > 2GiB MTD devices
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Bruce,

Since you don't want to change the ABI you need to extend it. Andrew, should
he add an new ioctl that passes a new structure definition? That way the
original code works and you have to do a new ioctl to get the new size data.

> -----Original Message-----
> From: linux-mtd-bounces@lists.infradead.org
> [mailto:linux-mtd-bounces@lists.infradead.org] On Behalf Of
> Bruce_Leonard@selinc.com
> Sent: Tuesday, August 26, 2008 6:21 PM
> To: Andrew Morton
> Cc: linux-mtd-bounces@lists.infradead.org;
> linux-mtd@lists.infradead.org; David Woodhouse;
> linux-kernel@vger.kernel.org; Bruce Leonard
> Subject: Re: [PATCH 2/2][MTD] Add support for > 2GiB MTD devices
>
> 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
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>



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