From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: regression: CD burning (k3b) went broke Date: Tue, 26 Feb 2008 15:08:45 -0800 Message-ID: <20080226150845.2196bc1a.akpm@linux-foundation.org> References: <1203583379.6244.27.camel@homer.simson.net> <20080222073228.GZ23197@kernel.dk> <1203752563.5225.4.camel@homer.simson.net> <1203839683.17463.9.camel@homer.simson.net> <1204019283.8731.11.camel@homer.simson.net> <1204033003.11828.22.camel@homer.simson.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1204033003.11828.22.camel@homer.simson.net> Sender: linux-scsi-owner@vger.kernel.org To: Mike Galbraith Cc: Jens Axboe , LKML , Tejun Heo , linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org List-Id: linux-ide@vger.kernel.org On Tue, 26 Feb 2008 14:36:43 +0100 Mike Galbraith wrote: > > On Tue, 2008-02-26 at 10:48 +0100, Mike Galbraith wrote: > > Greetings, > > > > I straced both a good and a bad kernel (good being .git with attached > > revert patch applied) and filtered/diffed/merged the output. Scroll > > down to "HERE" to see the problem (resid). > > > > I'm poking around, but not having much luck. cc's added. I'm told this is part of "Tejun's DMA drain handling". > Seems the problem is data_len changes, but raw_data_len doesn't. I've > not the foggiest IO-land clue, but k3b works again, so the below may > have some diagnostic value. So this change fixes a bug? Can we have a recap of how it does this? > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index ba21d97..7a6f784 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -871,7 +871,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) > scsi_end_bidi_request(cmd); > return; > } > - req->data_len = scsi_get_resid(cmd); > + req->data_len = req->raw_data_len = scsi_get_resid(cmd); > } > > BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */ > Thanks.