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[68.160.176.52]) by smtp.gmail.com with ESMTPSA id j13sm7195820qta.76.2022.01.11.08.15.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jan 2022 08:15:11 -0800 (PST) Date: Tue, 11 Jan 2022 11:15:09 -0500 From: Mike Snitzer To: Christoph Hellwig , Jens Axboe Cc: Ming Lei , dm-devel@redhat.com, linux-block@vger.kernel.org Subject: Re: [PATCH 0/3] blk-mq/dm-rq: support BLK_MQ_F_BLOCKING for dm-rq Message-ID: References: <20211221141459.1368176-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jan 11 2022 at 3:34P -0500, Christoph Hellwig wrote: > On Tue, Dec 28, 2021 at 04:30:08PM -0500, Mike Snitzer wrote: > > Yeah, people use request-based for IO scheduling and more capable path > > selectors. Imposing bio-based would be a pretty jarring workaround for > > BLK_MQ_F_BLOCKING. request-based DM should properly support it. > > Given that nvme-tcp is the only blocking driver that has multipath > driver that driver explicitly does not intend to support dm-multipath > I'm absolutely against adding block layer cruft for this particular > use case. this diffstat amounts to what you call "cruft": block/blk-core.c | 2 +- block/blk-mq.c | 6 +++--- block/blk-mq.h | 2 +- block/blk-sysfs.c | 2 +- block/genhd.c | 5 +++-- drivers/md/dm-rq.c | 5 ++++- drivers/md/dm-rq.h | 3 ++- drivers/md/dm-table.c | 14 ++++++++++++++ drivers/md/dm.c | 5 +++-- drivers/md/dm.h | 1 + include/linux/blkdev.h | 5 +++-- include/linux/genhd.h | 12 ++++++++---- 12 files changed, 44 insertions(+), 18 deletions(-) > SCSI even has this: > > /* > * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so > * calling synchronize_rcu() once is enough. > */ > WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING); > Round and round we go.. Pretty tired of this. You are perfectly fine with incrementally compromising request-based DM's ability to evolve as block core does. Seriously, this patchset shouldn't warrant bickering: https://patchwork.kernel.org/project/dm-devel/list/?series=598823 Jens, this incremental weakening of what it is that DM is allowed to do is not something I can continue to work with (nor should Ming's or others' contributions be rejected for such reasons). This tribal war needs to stop. Mike 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 572B6C433EF for ; Tue, 11 Jan 2022 16:20:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641918034; h=from:from:sender:sender: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:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=IgmLKYT+pJNQcqlHQ8BKZnbHOY5Kjv2kap79aR/Ybhw=; b=LO6usznaZqWYLeUGcWeeN/gmSbSp8sSaxXlYAPdQwnaojpil702CRnYrKX4lG2Wfj6QLfR 9OGtrmaFJYHIKGzZJO5fk5VCeNZcUx00xjju2p/ouHXEqQV9ZYQMsuuGtMVEScD911kAib zM1h8DiS9bEWB+Sw9C//vv0Cakm8GeM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-410-_M5lVHLDMe2PgGTNHoOAGg-1; Tue, 11 Jan 2022 11:20:30 -0500 X-MC-Unique: _M5lVHLDMe2PgGTNHoOAGg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 33E44101F01B; Tue, 11 Jan 2022 16:20:26 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4A482703B8; Tue, 11 Jan 2022 16:20:24 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 86B104BB7C; Tue, 11 Jan 2022 16:20:21 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 20BGKIlC000431 for ; Tue, 11 Jan 2022 11:20:18 -0500 Received: by smtp.corp.redhat.com (Postfix) id 832B8C33AE7; Tue, 11 Jan 2022 16:20:18 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast05.extmail.prod.ext.rdu2.redhat.com [10.11.55.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7EF30C33AE3 for ; Tue, 11 Jan 2022 16:20:18 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 63CD680A0B8 for ; Tue, 11 Jan 2022 16:20:18 +0000 (UTC) Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-586-n0-TbG-2PAClBtUp2h6y9A-1; Tue, 11 Jan 2022 11:20:17 -0500 X-MC-Unique: n0-TbG-2PAClBtUp2h6y9A-1 Received: by mail-qv1-f69.google.com with SMTP id r2-20020a0562140c4200b00418e57a7b35so1974729qvj.3 for ; Tue, 11 Jan 2022 08:20:17 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=CC1i5tpLMiW1d6bdv7f77XtvYY1n5qxfZPIldyU34eI=; b=yVocQL+Z9NhgqLt7T/1SzJB154ml+nckljRGvy/xIwJUNtC5ZUkYnhl1mvHMHOaxTP Hw6FivUkqWe4ahgG/rb2KC0Il/DJwLQR5nnk0U4hyK0WeEfrB71GUzX4H5pwirsU12Av L3p56e7VKUxLNPmmb0JzzVrHT8GN6zOSJN96UIcQFBKPjFBXvL6CbDPNfuBLXc6X7X00 F38YQAddN4OHuhs2IrwFR6Ez0yleYsERBAO0nIfmRblFIT+Tyq2lcMHhsNPTyFX1J9vb 7iWZOnnAFMpeBVILVcuDR89xJOzLiwqi33/8dw73IuZ667oAMkGb+xOFc5xsubL0Wsvp EYkw== X-Gm-Message-State: AOAM531N9X306ggw0ZO7mzVQ5OVHqtqrtl9GSAt+QlGfpbZvcV4IFHqM jyUMWVF9XhKzxf2Zcyz8JSHdhver2EzfuWMrVV9yUcjG/BA6x5Ly3o8Q1Cih+s2ITcQqU8ckL/v G3cGWP63PGbhRbQ== X-Received: by 2002:a05:622a:13ce:: with SMTP id p14mr4232669qtk.562.1641917712067; Tue, 11 Jan 2022 08:15:12 -0800 (PST) X-Google-Smtp-Source: ABdhPJz9rn8Dc2sri+sXStNgRwr2Ijq9qi5yvFpyULm8k4zkoftteb5wEjtKYGDbnDA0U+OKT8LYwQ== X-Received: by 2002:a05:622a:13ce:: with SMTP id p14mr4232630qtk.562.1641917711671; Tue, 11 Jan 2022 08:15:11 -0800 (PST) Received: from localhost (pool-68-160-176-52.bstnma.fios.verizon.net. [68.160.176.52]) by smtp.gmail.com with ESMTPSA id j13sm7195820qta.76.2022.01.11.08.15.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jan 2022 08:15:11 -0800 (PST) Date: Tue, 11 Jan 2022 11:15:09 -0500 From: Mike Snitzer To: Christoph Hellwig , Jens Axboe Message-ID: References: <20211221141459.1368176-1-ming.lei@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 X-loop: dm-devel@redhat.com Cc: linux-block@vger.kernel.org, dm-devel@redhat.com, Ming Lei Subject: Re: [dm-devel] [PATCH 0/3] blk-mq/dm-rq: support BLK_MQ_F_BLOCKING for dm-rq X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue, Jan 11 2022 at 3:34P -0500, Christoph Hellwig wrote: > On Tue, Dec 28, 2021 at 04:30:08PM -0500, Mike Snitzer wrote: > > Yeah, people use request-based for IO scheduling and more capable path > > selectors. Imposing bio-based would be a pretty jarring workaround for > > BLK_MQ_F_BLOCKING. request-based DM should properly support it. > > Given that nvme-tcp is the only blocking driver that has multipath > driver that driver explicitly does not intend to support dm-multipath > I'm absolutely against adding block layer cruft for this particular > use case. this diffstat amounts to what you call "cruft": block/blk-core.c | 2 +- block/blk-mq.c | 6 +++--- block/blk-mq.h | 2 +- block/blk-sysfs.c | 2 +- block/genhd.c | 5 +++-- drivers/md/dm-rq.c | 5 ++++- drivers/md/dm-rq.h | 3 ++- drivers/md/dm-table.c | 14 ++++++++++++++ drivers/md/dm.c | 5 +++-- drivers/md/dm.h | 1 + include/linux/blkdev.h | 5 +++-- include/linux/genhd.h | 12 ++++++++---- 12 files changed, 44 insertions(+), 18 deletions(-) > SCSI even has this: > > /* > * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so > * calling synchronize_rcu() once is enough. > */ > WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING); > Round and round we go.. Pretty tired of this. You are perfectly fine with incrementally compromising request-based DM's ability to evolve as block core does. Seriously, this patchset shouldn't warrant bickering: https://patchwork.kernel.org/project/dm-devel/list/?series=598823 Jens, this incremental weakening of what it is that DM is allowed to do is not something I can continue to work with (nor should Ming's or others' contributions be rejected for such reasons). This tribal war needs to stop. Mike -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel