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 2042CCD98F2 for ; Fri, 19 Jun 2026 18:45:54 +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=FBa36oetGM98CKDff4iQR1LHwkI39+FDS5gJw9MMV/g=; b=jQvV2uFzZeUujpH4+GfhVtFgsq 3xX7ig0shZTfDHxOol1bv/mypKQ4WoiS9xDulGOOELF0NwoFwu8EBgPQ060ENfKMzMgLmJgwVOifD fvL8wwJEbPwKFhv0b0uj24PfJHz2M6vLVH8Vmt/DTa28vhXDocbGEAJAhO+F+wGZeucCitNxc1ic4 auyii8TKa17HxSbbQQcRwyIZve4e0ihQVYlXI3Q9FnXRoeb9IkzNud3HLBrtUDiwxxo1U5JMGrl6k E1vns6ltyjwQi3xNK3MfjSTKiJ64xRtnl+WdKsI/6in9oQsHytQVS4b+z894//IbbdL91Au6zojtH UMcxuq0g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1waeDu-00000002tDX-3JYu; Fri, 19 Jun 2026 18:45:50 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1waeDs-00000002tDJ-3zog for linux-nvme@lists.infradead.org; Fri, 19 Jun 2026 18:45:49 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 36F66601E1; Fri, 19 Jun 2026 18:45:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71C901F000E9; Fri, 19 Jun 2026 18:45:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781894747; bh=FBa36oetGM98CKDff4iQR1LHwkI39+FDS5gJw9MMV/g=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=LUvuJba0n1qxs8+Uo/JYny0hhls3tq1Y9GEi5Y5BlP96op/MYpnRgKOndu6FYHi9p ABMyNUidg9ZUeKtxwIyX+ypGg9a2ESByu1BxCI3ItMixPtxnBeZJw3otEoeBlOymHP nJKbT094QZpe5NIyzMtWXEyONLLlnBtUTrzKJ8BQHpMkpdmXLKGCZpmNwJtnTNcbTr CT91PJ9TI6MdWbzC/y0vlzzi4L8L9691gtQt/qCaleyMtpsb0d28E+HQj6DfUgTyUd JXEVI5zHj3vXY5ToHQF+HxE9OIfv6m7j2rL5m7zspSuDE+COyN+MQ53P5T7R1goQjQ dok0tsokqXqdQ== Date: Fri, 19 Jun 2026 12:45:45 -0600 From: Keith Busch To: Hannes Reinecke Cc: Maurizio Lombardi , John Meneghini , Maurizio Lombardi , hch@lst.de, chaitanyak@nvidia.com, bvanassche@acm.org, linux-scsi@vger.kernel.org, linux-nvme@lists.infradead.org, James.Bottomley@hansenpartnership.com, emilne@redhat.com, bgurney@redhat.com Subject: Re: [PATCH V3 0/3] Ensure ordered namespace registration during async scan Message-ID: References: <20260225161203.76168-1-mlombard@redhat.com> <869034b1-c7e8-4e35-b153-43fd787a8edd@suse.de> <531aa19b-a9ae-44f7-82ce-3714621ceee8@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <531aa19b-a9ae-44f7-82ce-3714621ceee8@suse.de> 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 Fri, Jun 19, 2026 at 07:59:43AM +0200, Hannes Reinecke wrote: > The problem here is namespace lifetime. The ns_ida is only ever released > at the very last step, so the 'number' of the namespace will only be freed > once all references to the namespace are dropped. > So if you were trying to keep the namespace number ordered you would > have to delay the creation of the namespace until that point, and you > would induce a serialization between deletion and creation. Under the proposed scheme, there is no ns_ida. You just use the NSID of the namespace, and that's it. You have to ensure that del_gendisk completed on all heads and paths that was using it prior to bringing up the next one, but that's not really a problem. The problem I recall has something to do with the nsid not being a consistent value when migrating a namespace to another array or something like that. Not that we currently have proper support for such a thing...