Messages in this thread | | | Date | Fri, 2 Aug 2002 15:47:57 +0200 (MET DST) | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: A new ide warning message |
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On Fri, 2 Aug 2002, Jens Axboe wrote:
> On Fri, Aug 02 2002, Jens Axboe wrote: > > 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. > > I'll take that back. Having looked at Adam's changes there are perfectly > fine. I'm now putting my money on IDE breakage somewhere instead. It
Look again Jens. Adam's changes made IDE queue handling inconsistent. hint: 2 * 127 != 255
But noticed warning deals with design of ll_rw_blk.c. ;-) (right now max_segment_size have to be max bv->bv_len aligned)
Jens, please look at segment checking/counting code, it does it on bv->bv_len (4kb most likely) not sector granuality...
So for not 4kb aligned max_segment_size we will get new segment...
Best fix will be to make block layer count sectors not bv->bv_len...
btw. I like Adam's patch but it was draft not to include in mainline (?). -- Bartlomiej
> would be interesting to dump request state when this happens. Stephen, > can you reproduce this at will? > > -- > Jens Axboe
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