Re: [PATCH 2/2][MTD] Add support for > 2GiB MTD devices

From: Bruce_Leonard
Date: Tue Aug 26 2008 - 21:44:51 EST


linux-mtd-bounces@xxxxxxxxxxxxxxxxxxx wrote on 08/26/2008 04:55:36 PM:

> On Thu, 21 Aug 2008 19:00:55 -0700 (GMT-07:00)
> Bruce Leonard <brucle@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxx (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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