From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 6/8] bsg-lib: handle bidi requests without block layer help Date: Wed, 14 Nov 2018 16:48:57 +0100 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 Return-path: Content-Disposition: inline In-Reply-To: <20181113143520.GB7222@w530-pk1mzal> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-scsi@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.