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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3853FC636D0 for ; Mon, 30 Jan 2023 12:36:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236902AbjA3MgS (ORCPT ); Mon, 30 Jan 2023 07:36:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235273AbjA3MgQ (ORCPT ); Mon, 30 Jan 2023 07:36:16 -0500 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C636135; Mon, 30 Jan 2023 04:36:14 -0800 (PST) Received: by verein.lst.de (Postfix, from userid 2407) id 0544868D0A; Mon, 30 Jan 2023 13:36:11 +0100 (CET) Date: Mon, 30 Jan 2023 13:36:10 +0100 From: Christoph Hellwig To: Israel Rukshin Cc: Sagi Grimberg , Leon Romanovsky , Jason Gunthorpe , Bryan Tan , Christoph Hellwig , Eric Dumazet , Jakub Kicinski , Jens Axboe , Keith Busch , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Masami Hiramatsu , Max Gurtovoy , netdev@vger.kernel.org, Paolo Abeni , Saeed Mahameed , Selvin Xavier , Steven Rostedt , Vishnu Dasa , Yishai Hadas Subject: Re: [PATCH rdma-next 00/13] Add RDMA inline crypto support Message-ID: <20230130123610.GB19948@lst.de> References: <6f9da88c-f01e-156b-eb19-0b275c46c6b5@grimberg.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 23, 2023 at 02:57:18PM +0200, Israel Rukshin wrote: >> - what happens with multipathing? when if not all devices are >> capable. SW fallback? > SW fallback happens every time the device doesn't support the specific > crypto request (which include data-unit-size, mode and dun_bytes). > So with multipathing, one path uses the HW crypto offload and the other one > uses the SW fallback. That's a big no-go. The blk-crypto-fallback code is just a toy example and not actually safe to use in prodution. Most importantly it just kmallocs a bio clone and pages for it without any mempool that guarantees forward progress.