Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933603AbbELUzP (ORCPT ); Tue, 12 May 2015 16:55:15 -0400 Received: from mail-pa0-f44.google.com ([209.85.220.44]:36394 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932608AbbELUyz (ORCPT ); Tue, 12 May 2015 16:54:55 -0400 Date: Tue, 12 May 2015 03:59:07 -0700 From: Shaohua Li To: Maxime Ripard Cc: Neil Brown , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Lior Amsalem , Thomas Petazzoni , Gregory Clement , Boris Brezillon Subject: Re: Possible RAID6 regression with ASYNC_TX_DMA enabled in 4.1 Message-ID: <20150512105907.GA53461@kernel.org> References: <20150507125702.GI11057@lukather> <20150511062638.GA63893@kernel.org> <20150512125546.GJ10961@lukather> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150512125546.GJ10961@lukather> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2700 Lines: 64 On Tue, May 12, 2015 at 02:55:46PM +0200, Maxime Ripard wrote: > Hi Shaohua, > > On Sun, May 10, 2015 at 11:26:38PM -0700, Shaohua Li wrote: > > On Thu, May 07, 2015 at 02:57:02PM +0200, Maxime Ripard wrote: > > > Hi, > > > > > > I'm currently trying to add support for the PQ operations on the > > > marvell XOR engine, in dmaengine, obviously to be able to use async_tx > > > to offload these operations. > > > > > > I'm testing these patches with a RAID6 array with 4 disks. > > > > > > However, since the commit 59fc630b8b5f ("RAID5: batch adjacent full > > > stripe write", every write to that array fails with the following > > > stacktrace. > > > > > > http://code.bulix.org/eh8iew-88342?raw > > > > > > It seems to be generated by that warning here: > > > > > > http://lxr.free-electrons.com/source/crypto/async_tx/async_tx.c#L173 > > > > > > And indeed, if we dump the status of depend_tx here, it's already been > > > acked. > > > > > > That doesn't happen if ASYNC_TX_DMA is disabled, hence using the > > > software version of it, instead of relying on our XOR engine. It > > > doesn't happen on any commit prior to the one mentionned above, with > > > the exact same changes applied. These changes are meant to be > > > contributed, so I can definitely push them somewhere if needed. > > > > > > I don't really know where to look for though, the change that is > > > causing this is probably the change in ops_run_reconstruct6, but I'm > > > not sure that this partial revert alone would work with regard to the > > > rest of the patch. > > > > I don't have a machine with dmaengine, it's likely there is error in this side. > > Could you please make stripe_can_batch() returns false always and check if the > > error disappear? This should narrow down if it's related to batch issue. > > The error indeed disappears if stripe_can_batch always returns false. Does this fix it? diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 77dfd72..5e820fc 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -1825,7 +1825,7 @@ ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu, } else init_async_submit(&submit, 0, tx, NULL, NULL, to_addr_conv(sh, percpu, j)); - async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit); + tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit); if (!last_stripe) { j++; sh = list_first_entry(&sh->batch_list, struct stripe_head, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/