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Date: Fri, 2 Aug 2002 13:53:21 +0200
From: Jens Axboe <axboe@suse.de>
To: martin@dalecki.de
Cc: Stephen Lord <lord@sgi.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: A new ide warning message
Message-ID: <20020802115321.GE1055@suse.de>
References: <1028288066.1123.5.camel@laptop.americas.sgi.com> <3D4A6F43.4010908@evision.ag>
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On Fri, Aug 02 2002, Marcin Dalecki wrote:
> U?ytkownik Stephen Lord napisa?:
> >In 2.5.30 I started getting these warning messages out ide during
> >the mount of an XFS filesystem:
> >
> >ide-dma: received 1 phys segments, build 2
> >
> >Can anyone translate that into English please.
> 
> It can be found in pcidma.c.
> It is repoting that we have one physical segment needed by
> the request in question but the sctter gather list allocation
> needed to break it up for mapping in two.

You don't seem to realise that this is a BUG (somewhere, could even be
in the generic mapping functions)! blk_rq_map_sg() must never map a
request to more entries that rq->nr_segments, that's just very wrong.

That's why I'm suspecting the recent pcidma changes. Just a feeling, I
have not looked at them.

-- 
Jens Axboe

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