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From: Jens Axboe <axboe@suse.de>
To: "David S. Miller" <davem@davemloft.net>
Cc: aviro@redhat.com, torvalds@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: BLKSECTGET userland API breakage (2.4 and 2.6 incompatible)
Date: Fri, 14 Oct 2005 08:54:30 +0200	[thread overview]
Message-ID: <20051014065430.GQ6603@suse.de> (raw)
In-Reply-To: <20051013.210615.81985793.davem@davemloft.net>

On Thu, Oct 13 2005, David S. Miller wrote:
> From: Alexander Viro <aviro@redhat.com>
> 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


  reply	other threads:[~2005-10-14  6:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-13 23:49 BLKSECTGET userland API breakage (2.4 and 2.6 incompatible) Alexander Viro
2005-10-14  4:06 ` David S. Miller
2005-10-14  6:54   ` Jens Axboe [this message]
2005-10-14  6:53 ` Jens Axboe

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