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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2AA6EE8B386 for ; Wed, 4 Feb 2026 01:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xjBRAILllbiil6uqa4uIRKWQgWlKn8ntrdvr6J4sf/I=; b=BgiTf+q7XigGlNtHZBYbj2dlNp clxgkRdjk941hHhR1Wfbzmi/6w+aZvIW5xEmlBSQj1HTP12BpVesGTI9r+KIkn7lQrF/ai8CxOXsk rOhett0cBOTu9f/Lyi01vPfYvKxxL2q06NRO/SuHq2c9CR4vlyFQDaGYxQ9CTD50wOl6B0aCY+41d NxrmacgfJEv1m7Tjhryofvj7ZdGtZ8fr8i/Lte3147sMohDtorS7UpeKEik/WbepxYa7E2VHcog4x DF1jhxM7efWkbeaMAhDjEyBCKfVzbQR/3gJl5+GLBi8Zst9hraUacCJtKx/gGvyi/KzYNTyDtRanp DGDObngA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnRTJ-00000007fpg-2zIn; Wed, 04 Feb 2026 01:14:21 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnRTF-00000007fpL-3gfq for linux-nvme@lists.infradead.org; Wed, 04 Feb 2026 01:14:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770167656; 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: in-reply-to:in-reply-to:references:references; bh=xjBRAILllbiil6uqa4uIRKWQgWlKn8ntrdvr6J4sf/I=; b=BxD6ahImDD/Ao6NH0fLjyXC8JP2mmfY0LMZJOobyjp+LFZjVepUoj4toUATPNq5+/xOJdU mL8wWRZRXGnBX5TWD+I/wpmb2IRYqXSz78dmNmfyhkE27j0Vb14gCv3E9Joo8gR/V2PWHy Lv8yP969zX+mx4/ceiDhlOloOl7LVbE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-590-KSNMtdGmMBKhM-Cfzgz2eA-1; Tue, 03 Feb 2026 20:14:12 -0500 X-MC-Unique: KSNMtdGmMBKhM-Cfzgz2eA-1 X-Mimecast-MFC-AGG-ID: KSNMtdGmMBKhM-Cfzgz2eA_1770167651 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3A99C180034F; Wed, 4 Feb 2026 01:14:11 +0000 (UTC) Received: from fedora (unknown [10.72.116.35]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7EABE1800109; Wed, 4 Feb 2026 01:14:07 +0000 (UTC) Date: Wed, 4 Feb 2026 09:14:02 +0800 From: Ming Lei To: Hannes Reinecke Cc: lsf-pc , "linux-block@vger.kernel.org" , "linux-nvme@lists.infradead.org" Subject: Re: [LSF/MM/BFP TOPIC] Block-layer device resets Message-ID: References: <50ee77fa-0c44-422e-9ee2-eece60b189e1@suse.de> <65937263-912c-4250-af26-054b2b6be72b@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <65937263-912c-4250-af26-054b2b6be72b@suse.de> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260203_171417_985118_5BE3B1F4 X-CRM114-Status: GOOD ( 18.81 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Feb 03, 2026 at 06:51:25AM +0100, Hannes Reinecke wrote: > On 2/3/26 04:14, Ming Lei wrote: > > Hi Hannes, > > > > On Sun, Feb 01, 2026 at 06:06:52PM +0100, Hannes Reinecke wrote: > > > Hi all, > > > > > > We are currently working on implementing cross-controller resets for > > > NVMe, which requires to send a command to the target which then should > > > terminate all commands on a given controller. > > > > Can you provide a little background why this reset is required? And for > > solve which problem? > > > Sure. It got triggered by me wanting to use a ublk device as a backing > device for nvmet namespace. ublk supports it, either delete & re-add the disk or use UBLK_F_USER_RECOVERY & UBLK_F_QUIESCE for keeping disk node. > During a nvme reconnect the target is supposed to abort/flush all > outstanding commands on the backing device. As this is a block device > we would need to have an interface into the block layer allowing us > to do so. It could be hard to provide such generic(ioctl) block interface: 1) use queue freeze - hang risk, because some or many block devices don't implement timeout or error handling 2) use queue quiesce - still need driver cooperation for draining the inflight IOs Basically the hard part is in driver side. Thanks, Ming