From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4999C28CF5 for ; Wed, 26 Jan 2022 12:57:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241574AbiAZM52 (ORCPT ); Wed, 26 Jan 2022 07:57:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234510AbiAZM5Y (ORCPT ); Wed, 26 Jan 2022 07:57:24 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43805C06161C; Wed, 26 Jan 2022 04:57:24 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 10E43B81D05; Wed, 26 Jan 2022 12:57:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F6A8C340E3; Wed, 26 Jan 2022 12:57:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643201841; bh=WjSXJJLFgn///WXgXrWaxq0fyKyJj+v3auEVSwOjjsE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jorod1QGnXM7vSthuCy+/TApHtZgb8F+R/HZUUNCIf0joFXIqav099INEcgMDOEZP ovxvtlkkiy7oR3WbIjN0HDKAW5Ak3tIfNiGnu/yQGztZCLMFRbsghKnwC4ITpdkdjZ fPd3I3BN2Smrt32hvdHN5bTVR/cGwZFAa9gJ9YWM= Date: Wed, 26 Jan 2022 13:57:19 +0100 From: Greg Kroah-Hartman To: Jack Wang Cc: linux-kernel@vger.kernel.org, stable , Guoqing Jiang , Song Liu , Guillaume Morin Subject: Re: [PATCH 5.10 01/25] md: revert io stats accounting Message-ID: References: <20220114081542.698002137@linuxfoundation.org> <20220114081542.746291845@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 26, 2022 at 01:37:12PM +0100, Jack Wang wrote: > Greg Kroah-Hartman 于2022年1月26日周三 12:42写道： > > > > On Wed, Jan 26, 2022 at 11:09:46AM +0100, Jack Wang wrote: > > > Hi, > > > > > > Greg Kroah-Hartman 于2022年1月14日周五 19:57写道： > > > > > > > > From: Guoqing Jiang > > > > > > > > commit ad3fc798800fb7ca04c1dfc439dba946818048d8 upstream. > > > > > > > > The commit 41d2d848e5c0 ("md: improve io stats accounting") could cause > > > > double fault problem per the report [1], and also it is not correct to > > > > change ->bi_end_io if md don't own it, so let's revert it. > > > > > > > > And io stats accounting will be replemented in later commits. > > > > > > > > [1]. https://lore.kernel.org/linux-raid/3bf04253-3fad-434a-63a7-20214e38cf26@gmail.com/T/#t > > > > > > > > Fixes: 41d2d848e5c0 ("md: improve io stats accounting") > > > > Signed-off-by: Guoqing Jiang > > > > Signed-off-by: Song Liu > > > > [GM: backport to 5.10-stable] > > > > Signed-off-by: Guillaume Morin > > > > Signed-off-by: Greg Kroah-Hartman > > > > --- > > > > drivers/md/md.c | 57 +++++++++++--------------------------------------------- > > > > drivers/md/md.h | 1 > > > > 2 files changed, 12 insertions(+), 46 deletions(-) > > > > > > > > --- a/drivers/md/md.c > > > > +++ b/drivers/md/md.c > > > > @@ -459,34 +459,12 @@ check_suspended: > > > > } > > > > EXPORT_SYMBOL(md_handle_request); > > > > > > > > -struct md_io { > > > > - struct mddev *mddev; > > > > - bio_end_io_t *orig_bi_end_io; > > > > - void *orig_bi_private; > > > > - unsigned long start_time; > > > > - struct hd_struct *part; > > > > -}; > > > > - > > > > -static void md_end_io(struct bio *bio) > > > > -{ > > > > - struct md_io *md_io = bio->bi_private; > > > > - struct mddev *mddev = md_io->mddev; > > > > - > > > > - part_end_io_acct(md_io->part, bio, md_io->start_time); > > > > - > > > > - bio->bi_end_io = md_io->orig_bi_end_io; > > > > - bio->bi_private = md_io->orig_bi_private; > > > > - > > > > - mempool_free(md_io, &mddev->md_io_pool); > > > > - > > > > - if (bio->bi_end_io) > > > > - bio->bi_end_io(bio); > > > > -} > > > > - > > > > static blk_qc_t md_submit_bio(struct bio *bio) > > > > { > > > > const int rw = bio_data_dir(bio); > > > > + const int sgrp = op_stat_group(bio_op(bio)); > > > > struct mddev *mddev = bio->bi_disk->private_data; > > > > + unsigned int sectors; > > > > > > > > if (mddev == NULL || mddev->pers == NULL) { > > > > bio_io_error(bio); > > > > @@ -507,26 +485,21 @@ static blk_qc_t md_submit_bio(struct bio > > > > return BLK_QC_T_NONE; > > > > } > > > > > > > > - if (bio->bi_end_io != md_end_io) { > > > > - struct md_io *md_io; > > > > - > > > > - md_io = mempool_alloc(&mddev->md_io_pool, GFP_NOIO); > > > > - md_io->mddev = mddev; > > > > - md_io->orig_bi_end_io = bio->bi_end_io; > > > > - md_io->orig_bi_private = bio->bi_private; > > > > - > > > > - bio->bi_end_io = md_end_io; > > > > - bio->bi_private = md_io; > > > > - > > > > - md_io->start_time = part_start_io_acct(mddev->gendisk, > > > > - &md_io->part, bio); > > > > - } > > > > - > > > > + /* > > > > + * save the sectors now since our bio can > > > > + * go away inside make_request > > > > + */ > > > > + sectors = bio_sectors(bio); > > > This code snip is not inside the original patch, and it's not in > > > latest upstream too. > > > > /* bio could be mergeable after passing to underlayer */ > > > > bio->bi_opf &= ~REQ_NOMERGE; > > > > > > > > md_handle_request(mddev, bio); > > > > > > > > + part_stat_lock(); > > > > + part_stat_inc(&mddev->gendisk->part0, ios[sgrp]); > > > > + part_stat_add(&mddev->gendisk->part0, sectors[sgrp], sectors); > > > > + part_stat_unlock(); > > > > + > > > same here, this code snip is not inside the original patch, and it's > > > not in latest upstream too. > > > > Is it a problem? > Not sure, might cause some confusion regarding io stats. > > > > > I think would be good keep it as the upstream version. > > > > Can you send a revert of this commit (it is in 5.10.92), and a backport > > of the correct fix? > > > sure, I just sent an incremental fix for the backport itself. > is it ok? That works, I'll queue it up after this next round of releases, thanks! greg k-h