From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 1EBFB79EA for ; Wed, 12 Mar 2025 03:08:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741748929; cv=none; b=rMZHWomwYbVKainL3TH2ZVop6PbXI1a9qcRoOCLbQlP1t/qaConPKIpSxiHJJCx6LHSTZU+6ECzGhWzlBZRAklztzHUUEWd69FRBYnKpNkXDyIZsLoifOTUGJjf52wCOnI4E2DbqsS6+Q+n+nJ59ToZDtc/BdtsTeZBUsEd4AMk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741748929; c=relaxed/simple; bh=6zOPvTNiXKwH5hho8Ng+De+yAB8g8hyXwQGnyP/i/lE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tvfvXly4+2cD90SREd+m2rohr7rY2FnbJoEHIJcH7s/F8FekD3pygYylbHd5hCR4WWuWAVrGj2801+d6AI2pyIiv28YDrq1TjJ1BHf5pV9uI0S0gjCjgwEBf0NZ3HuMDTJ3Q8VMCG8yHRPjES1Uc/enACC+JDz+Ja4l5eWHEdxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=ZaoMwDRo; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="ZaoMwDRo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741748926; 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=VPbjQ3LyJEVdlvelmk4xTYprYRGR8Y0T9tIA9nw+UI0=; b=ZaoMwDRo9zXNHgy1kVgrUEcUgc8MzVaF6OjJZY0+Qmcd49DZUxulncHEmeAEFF6YdghR0Y 2YnrYa628PWyCgouJhdc/Etg9ix/OwBI6zEMHiE3dJw48ddoBRb9Et42x44EScknsE7keh Qq4Vs6PmgB9NoVk93T+Ckf1D3LVnNiU= 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-245-LP3YnjyvPRCORz_uBG9ITQ-1; Tue, 11 Mar 2025 23:08:43 -0400 X-MC-Unique: LP3YnjyvPRCORz_uBG9ITQ-1 X-Mimecast-MFC-AGG-ID: LP3YnjyvPRCORz_uBG9ITQ_1741748922 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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 D37B118007E1; Wed, 12 Mar 2025 03:08:41 +0000 (UTC) Received: from [10.22.65.26] (unknown [10.22.65.26]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 87FD21956094; Wed, 12 Mar 2025 03:08:38 +0000 (UTC) Message-ID: Date: Tue, 11 Mar 2025 23:08:37 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] nvme: remove multipath module parameter To: Hannes Reinecke , Keith Busch , Sagi Grimberg Cc: Nilay Shroff , hch@lst.de, bmarzins@redhat.com, Bryan Gurney , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Marco Patalano , axboe@kernel.dk References: <20250204211158.43126-1-bgurney@redhat.com> <7c588344-f019-4939-8a93-0a450481d4bc@redhat.com> <8a1730a1-1faf-4722-99e1-c3a85257b6f4@redhat.com> <2ff87386-c6db-4f2e-be91-213504d99a78@linux.ibm.com> <0656b66c-dd9c-495d-b1fc-4f09e763fa66@grimberg.me> <91ae613a-7b56-4ca0-b91c-6bc1eee798b8@suse.de> Content-Language: en-US From: John Meneghini Organization: RHEL Core Storge Team In-Reply-To: <91ae613a-7b56-4ca0-b91c-6bc1eee798b8@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On 2/26/25 4:55 AM, Hannes Reinecke wrote: > Plus there are some NVMe devices out there which _despite_ being PCIe do report NMIC and CMIC set > (I won't name names, if you came across them you'll know). This is causing stacking drivers (most notably MD) > to behave vastly different on hotplug. Having the module option is an easy way of debugging (and, in quite > some cases, fixing) the issue. So some MD driver configurations that use PCIe devices that report CMIC and NMIC need to turn off core.nvme_multipath. Is that what you're saying? Are these PCIe devices multiported? > If the module option really causes issues just make it read-only; that > way you can still set if if absolutely required, and at the same time > catch installations which try to modify it. If we do that the parameter can't be used to support use cases like your MD driver, or Kieth's ublk driver. /John