From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: 4.5-rc iser issues Date: Sun, 14 Feb 2016 18:29:56 +0200 Message-ID: <56C0AB84.9040004@dev.mellanox.co.il> References: <20160214074119.GA24558@infradead.org> <56C04294.3090701@dev.mellanox.co.il> <56C05000.1040001@dev.mellanox.co.il> <56C066AF.6050901@dev.mellanox.co.il> <56C088EA.1050901@dev.mellanox.co.il> <20160214152223.GA5323@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ming Lei , Christoph Hellwig Cc: linux-rdma , Ming Lin-SSI , "linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Jens Axboe List-Id: linux-rdma@vger.kernel.org > Hi Sagi, Hey, >> But I don't think simply not cloning the biovecs is the right thing >> to do in the end. This must be something with the bvec iterators. > > I agree with Christoph, and there might be issues somewhere. > Me too, it was just an isolation step... >> From the log: >> iser: sg[0] dma_addr:0x85FC06000 off:0x0 sz:0x200 dma_len:0x200 >> iser: sg[1] dma_addr:0x860334000 off:0x0 sz:0x200 dma_len:0x200 <-- gap >> iser: sg[2] dma_addr:0x860335000 off:0x0 sz:0x200 dma_len:0x200 <-- gap > > The above gap shouldn't have come since blk_bio_segment_split() splits > out one new bio if gap is detected. > > Sort of the following code can be added in driver or prep_fn to check if > bvec of the rq is correct: > > rq_for_each_segment(bvec, sc->request, iter) { > //check if there is gap between bvec > } I added this indication and the gap detection does trigger a bio split. > > I don't know how to use iser, and looks everything works fine after > I setup virt boundary as 4095 for null_blk by the attachment > patch. That's probably because it's artificial and there is no HW with a real limitation... > >> Full quote for Ming: >> >> On Sun, Feb 14, 2016 at 04:02:18PM +0200, Sagi Grimberg wrote: >>> >>>>> I'm bisecting now, there are a couple of patches from Ming in >>>>> the area of the bio splitting code... >>>>> >>>>> CC'ing Ming, Linux-block and Linux-nvme as iser is identical to nvme >>>>> wrt the virtual boundary so I think nvme will break as well. > > The bisected commit is merged to v4.3, and looks no such kind of > report from nvme. I'm wandering how can that be... because clearly iser is seeing gaps which like nvme, it can't handle those. Maybe this is scsi specific? -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html