From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id 10591246BB2 for ; Wed, 4 Feb 2026 01:14:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770167658; cv=none; b=s1/vwR/WdMY/UFWKq0AJJYrmiljxCssGhXsj0PYL1Fx04c1qzBc8uYgEnHUBwJpSws7NYI/UImw7nu0SH0kHba4NCtAg/uAVtn0QytwCiWLxXfbWKOn6KNxlyMdtCTIyfKrMK4gflfewzdPz5Whyhl27yYIbC1fhwD2wtiDLVFc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770167658; c=relaxed/simple; bh=fF9rFqhkHvJdYOKnvNTQJArc4LvOk6gTNLR29UcpJQQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YeYiuPdp5Puzdhjxyq/6lyXSnIl3yKnApopCm5oZLDDOzD/UNi6eJVfx0G3R4KjtXZjI0bzuwqDPlfWSJkOkdzh8zygNEpcuCasxRpooWdf5Wd+R6/XRgpn3pQUiPkiFvbl+n6o28b2aEWoH4nKaO2oNV/210tJYxwv/6+BEkyo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=EKrEyDJi; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EKrEyDJi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770167655; 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=EKrEyDJi9v7achi5qPCJlCk+hNXT7sQq2HnYKR/UYmwxizK1IGujeVyqLnNpLiT3lRIpZH Jy4LKFWMQbROF80beHeVeJfzBXaon1yjphpN0ZbZva9zaVwLc+Cco4H1RP8z3hFq462qpb 4J+DlCh0uVht1E4AvrcqCDckEg8u7CQ= 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> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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