From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH v2] sg: add SG_FLAG_Q_AT_TAIL flag Date: Thu, 5 Jun 2014 02:24:10 -0700 Message-ID: <20140605092410.GA727@infradead.org> References: <538F3416.5090306@interlog.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:38501 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750776AbaFEJYK (ORCPT ); Thu, 5 Jun 2014 05:24:10 -0400 Content-Disposition: inline In-Reply-To: <538F3416.5090306@interlog.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Douglas Gilbert Cc: SCSI development list , Christoph Hellwig , James Bottomley , openosd@gmail.com On Wed, Jun 04, 2014 at 10:58:30AM -0400, Douglas Gilbert wrote: > When the SG_IO ioctl was copied into the block layer and > later into the bsg driver, subtle differences emerged. > > One difference is the way injected commands are queued through > the block layer (i.e. this is not SCSI device queueing nor SATA > NCQ). Summarizing: > - SG_IO in the block layer: blk_exec*(at_head=false) > - sg SG_IO: at_head=true > - bsg SG_IO: at_head=true > > Some time ago Boaz Harrosh introduced a sg v4 flag called > BSG_FLAG_Q_AT_TAIL to override the bsg driver default. > This patch does the equivalent for the sg driver. Looks good, Reviewed-by: Christoph Hellwig Any chance to get a patch for the block-layer SG_IO code, too?