From patchwork Thu Feb 11 14:38:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Jeffery X-Patchwork-Id: 12083487 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=-16.3 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 autolearn=ham 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 BEEECC433DB for ; Thu, 11 Feb 2021 14:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78EF764E7E for ; Thu, 11 Feb 2021 14:48:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230414AbhBKOpx (ORCPT ); Thu, 11 Feb 2021 09:45:53 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:47272 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231175AbhBKOjo (ORCPT ); Thu, 11 Feb 2021 09:39:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613054292; 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; bh=hiNocEMoVCOJCjoJuJHwNdTMD22XPmPvh3ZcD7H6o0k=; b=c4f/Ns5JLN9K7RhjuSDQ4cV1/btwLXpnpW9juSwGxyt72kvcYTiW2IlfatozdJn3rdJx82 Kn4aEIvnPA4o9tn+rUR2UHd27ZIYva09VGnjaOKZGlwva6xlEnt/d2kDRcihsIEzMaawep Um2+D6gQQYUR5GvKZE5A3ZWQ8TnF7yo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-564-EKX8R9EnOR61z6ryhnXqtA-1; Thu, 11 Feb 2021 09:38:11 -0500 X-MC-Unique: EKX8R9EnOR61z6ryhnXqtA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F15AA100A626; Thu, 11 Feb 2021 14:38:09 +0000 (UTC) Received: from redhat (ovpn-115-60.rdu2.redhat.com [10.10.115.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7A1761A26A; Thu, 11 Feb 2021 14:38:09 +0000 (UTC) Date: Thu, 11 Feb 2021 09:38:07 -0500 From: David Jeffery To: linux-block@vger.kernel.org Cc: Jens Axboe , linux-kernel@vger.kernel.org Subject: [PATCH v2] block: recalculate segment count for multi-segment discards correctly Message-ID: <20210211143807.GA115624@redhat> MIME-Version: 1.0 Content-Disposition: inline X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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. Fixes: 1e739730c5b9 ("block: optionally merge discontiguous discard bios into a single request") Signed-off-by: David Jeffery Reviewed-by: Ming Lei Reviewed-by: Laurence Oberman --- V2 explicitly returns 1 instead of falling through in the no-multi case and handles REQ_OP_SECURE_ERASE like REQ_OP_DISCARD. block/blk-merge.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/blk-merge.c b/block/blk-merge.c index 808768f6b174..756473295f19 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -383,6 +383,14 @@ unsigned int blk_recalc_rq_segments(struct request *rq) switch (bio_op(rq->bio)) { case REQ_OP_DISCARD: case REQ_OP_SECURE_ERASE: + if (queue_max_discard_segments(rq->q) > 1) { + struct bio *bio = rq->bio; + + for_each_bio(bio) + nr_phys_segs++; + return nr_phys_segs; + } + return 1; case REQ_OP_WRITE_ZEROES: return 0; case REQ_OP_WRITE_SAME: