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 X-Spam-Level: X-Spam-Status: No, score=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9411C433E0 for ; Thu, 4 Feb 2021 16:48:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 983B564DF5 for ; Thu, 4 Feb 2021 16:48:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237916AbhBDQsw (ORCPT ); Thu, 4 Feb 2021 11:48:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:25146 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238118AbhBDQoo (ORCPT ); Thu, 4 Feb 2021 11:44:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612456997; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NL/hGyxQxHl7d50dBo9b5vP+PtbfiIT7+xqssL/xqJw=; b=QrtPugUNQYYuQ6OODNTPYIEKU5VwIcAq3DVWNAc5ClM8UIKbZylzh8NHZY3trYXuMFa9Jv Cc6it77nE/RH+8IjY2EBdhcOLPtE4xAwWBVSSEdd4tJ6qTff5VlgBIcxyGyPcRgOs9gW/C ox+ldZUWNe5U1GE9lQz2iPkVJ2UxOrI= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-352-YR5H34ykME20BMrMd-1OTA-1; Thu, 04 Feb 2021 11:43:15 -0500 X-MC-Unique: YR5H34ykME20BMrMd-1OTA-1 Received: by mail-qk1-f199.google.com with SMTP id 70so3166516qkh.4 for ; Thu, 04 Feb 2021 08:43:15 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=NL/hGyxQxHl7d50dBo9b5vP+PtbfiIT7+xqssL/xqJw=; b=kaNMrOmgXK736lXr78m73L+5L37oyxU4XYbEeLJdUoorYEHv9daXnXeTbVwlQfRIpc 8utj96awiEjnB9jm+Z3DqwV4HYiHjNgNUxM2T+HiPA07ucfoFGYhaYrnhx+05I1Jaedf Kf4VImeCFU/F1W4bN93SYYlpyQ8FUflhoCiDGnEYVF+JWFu9BkPd9lxAU4eAtbsiGwRX CgwwFnOryMxjkVYKLecsmJOrNGGiNyFU/+afpfYO6igDSBGb2r08vyuUwTAtZsEfUbB1 KhiOu4pv79CfQrJTN1brdCvaqWsCf8Z5/wVFhr/0lW5dhRMloYDnb+XlBgkHFT9Ihjba L+7g== X-Gm-Message-State: AOAM531vd97HD9o/UBmTbPEB0X3iCeYaSEMfZTDP0MadCEoiyeQYSvTB pYKqSlLjB4lJXZuIFqwn4plwQrMxvHdYiLF7YpGfuF11MXBO4GPruz7t4hI1nZhJhvVXDNIUQII MK2nViT4MIZ5KT5bK5CJohWXN X-Received: by 2002:a37:4fd1:: with SMTP id d200mr8710514qkb.201.1612456995247; Thu, 04 Feb 2021 08:43:15 -0800 (PST) X-Google-Smtp-Source: ABdhPJw/zFRFml2EJzN07EyuZAIoICrKhLwwhJRRSgoHH5GwsiKMlWYv4rxda/9teezeclY+Bpc0fw== X-Received: by 2002:a37:4fd1:: with SMTP id d200mr8710491qkb.201.1612456994986; Thu, 04 Feb 2021 08:43:14 -0800 (PST) Received: from loberhel7laptop ([2600:6c64:4e7f:cee0:ccad:a4ca:9a69:d8bc]) by smtp.gmail.com with ESMTPSA id b16sm5432387qkh.21.2021.02.04.08.43.14 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Feb 2021 08:43:14 -0800 (PST) Message-ID: <8ce70420d1dcb5dd0ffc73aaa38d8ce61eb19cff.camel@redhat.com> Subject: Re: [PATCH] block: recalculate segment count for multi-segment discard requests correctly From: Laurence Oberman To: Ming Lei , David Jeffery Cc: linux-block@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org Date: Thu, 04 Feb 2021 11:43:08 -0500 In-Reply-To: <20210204022740.GB1108591@T590> References: <20210201164850.391332-1-djeffery@redhat.com> <20210204022740.GB1108591@T590> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2021-02-04 at 10:27 +0800, Ming Lei wrote: > On Mon, Feb 01, 2021 at 11:48:50AM -0500, David Jeffery wrote: > > When a stacked block device inserts a request into another block > > device > > using blk_insert_cloned_request, the request's nr_phys_segments > > field gets > > recalculated by a call to blk_recalc_rq_segments in > > blk_cloned_rq_check_limits. But blk_recalc_rq_segments does not > > know how to > > handle multi-segment discards. For disk types which can handle > > multi-segment discards like nvme, this results in discard requests > > which > > claim a single segment when it should report several, triggering a > > warning > > in nvme and causing nvme to fail the discard from the invalid > > state. > > > > WARNING: CPU: 5 PID: 191 at drivers/nvme/host/core.c:700 > > nvme_setup_discard+0x170/0x1e0 [nvme_core] > > ... > > nvme_setup_cmd+0x217/0x270 [nvme_core] > > nvme_loop_queue_rq+0x51/0x1b0 [nvme_loop] > > __blk_mq_try_issue_directly+0xe7/0x1b0 > > blk_mq_request_issue_directly+0x41/0x70 > > ? blk_account_io_start+0x40/0x50 > > dm_mq_queue_rq+0x200/0x3e0 > > blk_mq_dispatch_rq_list+0x10a/0x7d0 > > ? __sbitmap_queue_get+0x25/0x90 > > ? elv_rb_del+0x1f/0x30 > > ? deadline_remove_request+0x55/0xb0 > > ? dd_dispatch_request+0x181/0x210 > > __blk_mq_do_dispatch_sched+0x144/0x290 > > ? bio_attempt_discard_merge+0x134/0x1f0 > > __blk_mq_sched_dispatch_requests+0x129/0x180 > > blk_mq_sched_dispatch_requests+0x30/0x60 > > __blk_mq_run_hw_queue+0x47/0xe0 > > __blk_mq_delay_run_hw_queue+0x15b/0x170 > > blk_mq_sched_insert_requests+0x68/0xe0 > > blk_mq_flush_plug_list+0xf0/0x170 > > blk_finish_plug+0x36/0x50 > > xlog_cil_committed+0x19f/0x290 [xfs] > > xlog_cil_process_committed+0x57/0x80 [xfs] > > xlog_state_do_callback+0x1e0/0x2a0 [xfs] > > xlog_ioend_work+0x2f/0x80 [xfs] > > process_one_work+0x1b6/0x350 > > worker_thread+0x53/0x3e0 > > ? process_one_work+0x350/0x350 > > kthread+0x11b/0x140 > > ? __kthread_bind_mask+0x60/0x60 > > ret_from_fork+0x22/0x30 > > > > This patch fixes blk_recalc_rq_segments to be aware of devices > > which can > > have multi-segment discards. It calculates the correct discard > > segment > > count by counting the number of bio as each discard bio is > > considered its > > own segment. > > > > Signed-off-by: David Jeffery > > Tested-by: Laurence Oberman > > --- > > block/blk-merge.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/block/blk-merge.c b/block/blk-merge.c > > index 808768f6b174..fe7358bd5d09 100644 > > --- a/block/blk-merge.c > > +++ b/block/blk-merge.c > > @@ -382,6 +382,13 @@ unsigned int blk_recalc_rq_segments(struct > > request *rq) > > > > switch (bio_op(rq->bio)) { > > case REQ_OP_DISCARD: > > + if (queue_max_discard_segments(rq->q) > 1) { > > + struct bio *bio = rq->bio; > > + for_each_bio(bio) > > + nr_phys_segs++; > > + return nr_phys_segs; > > + } > > + /* fall through */ > > case REQ_OP_SECURE_ERASE: > > case REQ_OP_WRITE_ZEROES: > > return 0; > > blk_rq_nr_discard_segments() always returns >=1 segments, so no > similar > issue in case of single range discard. > > Reviewed-by: Ming Lei > > And it can be thought as: > > Fixes: 1e739730c5b9 ("block: optionally merge discontiguous discard > bios into a single request") > > Great, can we get enough acks and push this through its urgent for me Reviewed-by: Laurence Oberman