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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32435C43441 for ; Wed, 14 Nov 2018 15:49:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0714B214F1 for ; Wed, 14 Nov 2018 15:49:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0714B214F1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733309AbeKOBwq (ORCPT ); Wed, 14 Nov 2018 20:52:46 -0500 Received: from verein.lst.de ([213.95.11.211]:35778 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732950AbeKOBwq (ORCPT ); Wed, 14 Nov 2018 20:52:46 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id A318868CF7; Wed, 14 Nov 2018 16:48:57 +0100 (CET) Date: Wed, 14 Nov 2018 16:48:57 +0100 From: Christoph Hellwig To: Benjamin Block Cc: Christoph Hellwig , axboe@kernel.dk, martin.petersen@oracle.com, ooo@electrozaur.com, Johannes Thumshirn , Benjamin Block , linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/8] bsg-lib: handle bidi requests without block layer help Message-ID: <20181114154857.GA28985@lst.de> References: <20181111133211.13926-1-hch@lst.de> <20181111133211.13926-7-hch@lst.de> <20181113143520.GB7222@w530-pk1mzal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181113143520.GB7222@w530-pk1mzal> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Nov 13, 2018 at 03:35:20PM +0100, Benjamin Block wrote: > This seems like a non-obvious user-breakage. So apart from removing the > in-kernel stuff that uses bidirectional commands you also forbid > userspace from every using them? That seems wrong to me. > > There is other SCSI Command Sets than OSD that provide bidirectional > commands, even SBC has some (i.e. X*WRITE*, COMPARE AND WRITE). Yes, there are a few. But the only driver that even supports them right now is iscsi_tcp to start with, and we have to drag a significant amount of code around just to support this corner case.