From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch 3/5] vfs: introduce FMODE_NEG_OFFSET for allowing
 negative f_pos
Date: Tue, 20 Jul 2010 21:03:29 -0700
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	<20100721115359.01b5d2b8.kamezawa.hiroyu@jp.fujitsu.com>
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Cc: Nick Piggin <npiggin@suse.de>, viro@zeniv.linux.org.uk,
	linux-fsdevel@vger.kernel.org, fengguang.wu@intel.com,
	heiko.carstens@de.ibm.com
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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On Wed, 21 Jul 2010 11:53:59 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> On Wed, 21 Jul 2010 12:54:37 +1000
> Nick Piggin <npiggin@suse.de> wrote:
> 
> > On Tue, Jul 20, 2010 at 03:29:48PM -0700, Andrew Morton wrote:
> > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> > > 
> > > Now, rw_verify_area() checsk f_pos is negative or not.  And if negative,
> > > returns -EINVAL.
> > > 
> > > But, some special files as /dev/(k)mem and /proc/<pid>/mem etc..  has
> > > negative offsets.  And we can't do any access via read/write to the
> > > file(device).
> > > 
> > > So introduce FMODE_NEG_OFFSET to allow negative file offsets.
> > 
> > Minor nitpick but I don't understand why this is called NEG_OFFSET. It's
> > a large positive offset into the file so FMODE_UNSIGNED_OFFSET seems
> > like it would be better.
> > 
> Ah, agreed.
> 
> I'll prepare a macro-renaming patch later (if this patch goes now.)

It won't.  I hand-edited the diff...