From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DF6CC325711; Sat, 21 Feb 2026 17:41:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771695690; cv=none; b=cbdZLcNvWzNk0blabFPH+RPI81ec+vEnD1jgxdNaeOlxT/76qy0phHtKxbR9bdVAdnkzC0FGWK7KwNIVPi0JG8DHhPojSF9vdf/gdVnA9ov6tqyZ+C/W0D/wW6KSTIgAPKhW0chidQ81V2EC+7sGhJPn1luEIaPryUHaQ+hkZmM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771695690; c=relaxed/simple; bh=hC/bKukwvz707+9AogQXTJbFdJshNSgSwFm4eZcmcjM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HIk4tGWNo3rbApJH1uchWDSInGaQ+EgHfzSMo0zeH7W/N40spk30bSh3c36dXD+e1CQ9zK+rFrf2TKl6FaP3ZwPWhjg4qzr0Yf360NcSYp63AmVyhyjUO3/+yrXOkZ9d+7JGqXQjEGTdmdCP/NMwXbp9Bjwm/ZHSuVKmoOr58q0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZLZY01/u; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZLZY01/u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44B31C4CEF7; Sat, 21 Feb 2026 17:41:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771695690; bh=hC/bKukwvz707+9AogQXTJbFdJshNSgSwFm4eZcmcjM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZLZY01/u2Mj5XoC/TEIMxkn1Fyn4UOpnYAx04p7FeFCEMq1SbrqBA5WkhzTtI6kZb QFBx2zeeeONDEz0vZwpr1znz0VM59flDkyZUsvQ11iRioTnfrZY5b02mfaBO49+xkT gVIGx9J54pngaVg75opSFOrSuBqPazXU6im3VACIsoci3hh+mvxcqgHmuyOmrFJxlk PM3x4aiUzSceUFq3RvIcK9e6yWTGZYZgn4p1RIPgV1Lvzjful53O01jX92CcsdvXef C+BwuALX2iFuZVFbMf3f5j+3hnw2jdxCRNw49xhYSPafldjS/KvQ8ZczKvKSKrh8Bd jINjZMvYA9SXg== Date: Sat, 21 Feb 2026 12:41:28 -0500 From: Mike Snitzer To: John Garry Cc: lsf-pc@lists.linux-foundation.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, dm-devel@lists.linux.dev Subject: Re: [LSF/MM/BPF TOPIC] Native SCSI multipath support Message-ID: References: <69349b51-72c2-47f9-948f-f89843af62e4@oracle.com> 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: <69349b51-72c2-47f9-948f-f89843af62e4@oracle.com> On Fri, Feb 13, 2026 at 02:19:11PM +0000, John Garry wrote: > At ALPSS 25 I presented a proposal for Native SCSI multipath support. Let's > discuss this topic at LSFMM. > > The idea for this is that SCSI could natively support multipath, like how > NVMe host driver does today. It is intended as an alternative to > dm-multipath support. > > I have been working on the implementation and I plan to post patches in the > next cycle. I am looking at a 3-stage approach: > a. create a driver-agnostic multipath library, very heavily based on NVMe > host multipath support. > The library would support features such as path management, path > selection/iopolicy, failover recovery, PR, delayed removal, gendisk > management etc. > b. switch NVMe over to use this library I can appreciate that the kernel to userspace interface of DM multipath is clearly unwanted (hence NVMe multipath and now SCSI multipath). But you should really be switching DM-multipath over to using it too; or at least detailing _why_ the core of DM multipath (drivers/md/dm-mpath.c) cannot be updated to use this common backend library. This line of work makes little sense to me if it just ignores dm-multipath. Mike > c. add native SCSI multipath support based on this common library > > Thanks, > John > > >