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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 E7AF8C07E95 for ; Fri, 16 Jul 2021 09:33:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D218F613EE for ; Fri, 16 Jul 2021 09:33:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233883AbhGPJgU (ORCPT ); Fri, 16 Jul 2021 05:36:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30069 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232617AbhGPJgT (ORCPT ); Fri, 16 Jul 2021 05:36:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626428004; 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=m08xqBA+uGZoSfDv0tyerS1nF0XIak+eyqoZwC+cyQU=; b=fs+uiCL+FgX9B4Y7CzNcyliC87vtZtwMV4adJC3RD6CV7gFLE38p+4ZAqBQhxtxmL3O6Oi E5OrOTQabtzve7ABKXGhJA6iTjDHtndUoQBwwmKWsvTjnQMIjeQNslBEsgi0PHRQrxLdSN kTVURCL7orejL2/YPVRswQQmp4YtVsY= 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-561-RuIirQ95PvymlHJa_zgO6g-1; Fri, 16 Jul 2021 05:33:23 -0400 X-MC-Unique: RuIirQ95PvymlHJa_zgO6g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 362F5CC621; Fri, 16 Jul 2021 09:33:21 +0000 (UTC) Received: from T590 (ovpn-13-146.pek2.redhat.com [10.72.13.146]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E5136604CD; Fri, 16 Jul 2021 09:33:10 +0000 (UTC) Date: Fri, 16 Jul 2021 17:33:05 +0800 From: Ming Lei To: Oleksandr Natalenko Cc: linux-kernel@vger.kernel.org, Jens Axboe , Christoph Hellwig , Sagi Grimberg , linux-nvme@lists.infradead.org, David Jeffery , Laurence Oberman , Paolo Valente , Jan Kara , Sasha Levin , Greg Kroah-Hartman , Keith Busch Subject: Re: New warning in nvme_setup_discard Message-ID: References: <4729812.CpyZKHjjVO@natalenko.name> <81322754.HEIg0oD171@natalenko.name> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <81322754.HEIg0oD171@natalenko.name> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 16, 2021 at 07:53:28AM +0200, Oleksandr Natalenko wrote: > Hello. > > On pátek 16. července 2021 4:16:18 CEST Ming Lei wrote: > > > 850 if (WARN_ON_ONCE(n != segments)) { > > > > What is 'n' and 'segments'? > > So, I used this change to check that: > > ``` > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index 66973bb56305..0a64f2f77daf 100644 > --- a/drivers/nvme/host/core.c > +++ b/drivers/nvme/host/core.c > @@ -847,7 +847,8 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, > struct request *req, > n++; > } > > - if (WARN_ON_ONCE(n != segments)) { > + if (unlikely(n != segments)) { > + pr_warn("nvme_setup_discard: n != segments (%u != %u)\n", n, > segments); > if (virt_to_page(range) == ns->ctrl->discard_page) > clear_bit_unlock(0, &ns->ctrl->discard_page_busy); > else > > ``` > > and the result is: > > ``` > nvme_setup_discard: n != segments (3 != 2) > nvme_setup_discard: n != segments (12 != 11) > ``` Can you test the following patch? diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 727955918563..673a634eadd9 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -2361,6 +2361,9 @@ static int bfq_request_merge(struct request_queue *q, struct request **req, __rq = bfq_find_rq_fmerge(bfqd, bio, q); if (__rq && elv_bio_merge_ok(__rq, bio)) { *req = __rq; + + if (blk_discard_mergable(__rq)) + return ELEVATOR_DISCARD_MERGE; return ELEVATOR_FRONT_MERGE; } diff --git a/block/blk-merge.c b/block/blk-merge.c index a11b3b53717e..f8707ff7e2fc 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -705,22 +705,6 @@ static void blk_account_io_merge_request(struct request *req) } } -/* - * Two cases of handling DISCARD merge: - * If max_discard_segments > 1, the driver takes every bio - * as a range and send them to controller together. The ranges - * needn't to be contiguous. - * Otherwise, the bios/requests will be handled as same as - * others which should be contiguous. - */ -static inline bool blk_discard_mergable(struct request *req) -{ - if (req_op(req) == REQ_OP_DISCARD && - queue_max_discard_segments(req->q) > 1) - return true; - return false; -} - static enum elv_merge blk_try_req_merge(struct request *req, struct request *next) { diff --git a/block/elevator.c b/block/elevator.c index 52ada14cfe45..a5fe2615ec0f 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -336,6 +336,9 @@ enum elv_merge elv_merge(struct request_queue *q, struct request **req, __rq = elv_rqhash_find(q, bio->bi_iter.bi_sector); if (__rq && elv_bio_merge_ok(__rq, bio)) { *req = __rq; + + if (blk_discard_mergable(__rq)) + return ELEVATOR_DISCARD_MERGE; return ELEVATOR_BACK_MERGE; } diff --git a/block/mq-deadline-main.c b/block/mq-deadline-main.c index 6f612e6dc82b..294be0c0db65 100644 --- a/block/mq-deadline-main.c +++ b/block/mq-deadline-main.c @@ -677,6 +677,8 @@ static int dd_request_merge(struct request_queue *q, struct request **rq, if (elv_bio_merge_ok(__rq, bio)) { *rq = __rq; + if (blk_discard_mergable(__rq)) + return ELEVATOR_DISCARD_MERGE; return ELEVATOR_FRONT_MERGE; } } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 3177181c4326..87f00292fd7a 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1521,6 +1521,22 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector return offset << SECTOR_SHIFT; } +/* + * Two cases of handling DISCARD merge: + * If max_discard_segments > 1, the driver takes every bio + * as a range and send them to controller together. The ranges + * needn't to be contiguous. + * Otherwise, the bios/requests will be handled as same as + * others which should be contiguous. + */ +static inline bool blk_discard_mergable(struct request *req) +{ + if (req_op(req) == REQ_OP_DISCARD && + queue_max_discard_segments(req->q) > 1) + return true; + return false; +} + static inline int bdev_discard_alignment(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev); Thanks, Ming