From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030416AbbD1QBe (ORCPT ); Tue, 28 Apr 2015 12:01:34 -0400 Received: from mga14.intel.com ([192.55.52.115]:42469 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965886AbbD1QBb (ORCPT ); Tue, 28 Apr 2015 12:01:31 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,664,1422950400"; d="scan'208";a="717190909" Date: Tue, 28 Apr 2015 16:01:26 +0000 (UTC) From: Keith Busch X-X-Sender: vmware@localhost.lm.intel.com To: Christoph Hellwig cc: Ming Lin , linux-kernel@vger.kernel.org, Jens Axboe , Kent Overstreet , Dongsu Park , Christoph Hellwig , Al Viro , Ming Lei , Neil Brown , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Lars Ellenberg , drbd-user@lists.linbit.com, Jiri Kosina , Geoff Levand , Jim Paris , Joshua Morris , Philip Kelleher , Minchan Kim , Nitin Gupta , Oleg Drokin , Andreas Dilger , Keith Busch Subject: Re: [PATCH 01/10] block: make generic_make_request handle arbitrarily sized bios In-Reply-To: <20150428114320.GA9790@lst.de> Message-ID: References: <1430203717-13307-1-git-send-email-mlin@kernel.org> <1430203717-13307-2-git-send-email-mlin@kernel.org> <20150428114320.GA9790@lst.de> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 28 Apr 2015, Christoph Hellwig wrote: > This seems to lack support for QUEUE_FLAG_SG_GAPS to work around > the retarded PPR format in the NVMe driver. Might strong words, sir! I'm missing the context here, but I'll say PRP is much more efficient for h/w to process over SGL, and the requirement comes from that h/w rather than the driver.