Re: BLKSECTGET userland API breakage (2.4 and 2.6 incompatible)

[Jens Axboe]

On Thu, Oct 13 2005, David S. Miller wrote:
> From: Alexander Viro <aviro@xxxxxxxxxx>
> Date: Thu, 13 Oct 2005 19:49:34 -0400
> 
> > all 2.4:      BLKSECTGET takes long * and is supported by several block drivers
> > bio-14-pre9:  Takes BLKSECTGET to drivers/block/blkpg.c, defining it for all
> >               block drivers *AND* making it take unsigned short *
> > 2.5.1-pre2:   bio merge
> > all 2.[56] kernels since then: BLKSECTGET takes unsigned short *
> > 32bit compat: unchanged since 2.4 and thus broken on 2.[56]
> > applications: we have seen ones using 2.6 ABI and getting buggered in
> >               32bit compat.  Most likely there are some using 2.4 ABI...
> > 
> > IMO the least painful variant is to switch 2.6 compat code to match
> > 2.6 native (i.e. use COMPATIBLE_IOCTL()), leave 2.4 as-is and live
> > with the fact of userland ABI change between 2.4 and 2.6...
> 
> Well, what's the userland state and why in the world did this
> happen in the first place?

Given that this change happened over 4 years ago, I cannot remember the
details of it. But it wasn't a conscious decision to change it, must
have been an unfortunate typo when killing maxsectors[].

-- 
Jens Axboe

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