From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: Re: [PATCH v5 17/21] libnvdimm: infrastructure for btt devices Date: Wed, 17 Jun 2015 09:50:33 -0700 Message-ID: References: <20150602001134.4506.45867.stgit@dwillia2-desk3.amr.corp.intel.com> <20150602001541.4506.90125.stgit@dwillia2-desk3.amr.corp.intel.com> <20150609064200.GE9804@lst.de> <20150610184616.GL2729@linux.intel.com> <20150611072812.GB1905@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jeff Moyer Cc: Christoph Hellwig , Matthew Wilcox , Jens Axboe , Stephen Rothwell , Andrew Morton , "Rafael J. Wysocki" , Neil Brown , Greg KH , linux-nvdimm , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Ingo Molnar , Linux ACPI , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-acpi@vger.kernel.org On Wed, Jun 17, 2015 at 9:47 AM, Jeff Moyer wrote: > Christoph Hellwig writes: > >> On Wed, Jun 10, 2015 at 02:46:16PM -0400, Matthew Wilcox wrote: >>> Don't screw up rw_page. The point of rw_page is to read or write a page >>> cache page. It can sleep, and it indicates success by using the page >>> flags. Don't try and scqueeze rw_bytes into it. If you want rw_bytes >>> to be a queue operation, that's one thing, but don't mess with rw_page. >> >> Oh, I forgot about the page manipulating nature. Yes, we'll need a different >> operation in this case. > > I didn't see this addressed in the new patch set. I'm also concerned > about the layering, but I haven't put enough time into it to really make > a better suggestion. I really dislike the idea of yet another device > stacking model in the kernel and I'm worried the code will go in, and the > sysfs interface will end up as a "user abi" and we won't be able to > change it in the future. > > Dan, have you made any progress on this, or do you have plans to? ? in v6 ->rw_bytes() moved from libnvdimm local hackery to a top-level block device operation. Is that your concern or something else? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755408AbbFQQun (ORCPT ); Wed, 17 Jun 2015 12:50:43 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:38127 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753584AbbFQQue (ORCPT ); Wed, 17 Jun 2015 12:50:34 -0400 MIME-Version: 1.0 In-Reply-To: References: <20150602001134.4506.45867.stgit@dwillia2-desk3.amr.corp.intel.com> <20150602001541.4506.90125.stgit@dwillia2-desk3.amr.corp.intel.com> <20150609064200.GE9804@lst.de> <20150610184616.GL2729@linux.intel.com> <20150611072812.GB1905@lst.de> Date: Wed, 17 Jun 2015 09:50:33 -0700 Message-ID: Subject: Re: [PATCH v5 17/21] libnvdimm: infrastructure for btt devices From: Dan Williams To: Jeff Moyer Cc: Christoph Hellwig , Matthew Wilcox , Jens Axboe , Stephen Rothwell , Andrew Morton , "Rafael J. Wysocki" , Neil Brown , Greg KH , linux-nvdimm , "linux-kernel@vger.kernel.org" , Ingo Molnar , Linux ACPI , linux-api@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 17, 2015 at 9:47 AM, Jeff Moyer wrote: > Christoph Hellwig writes: > >> On Wed, Jun 10, 2015 at 02:46:16PM -0400, Matthew Wilcox wrote: >>> Don't screw up rw_page. The point of rw_page is to read or write a page >>> cache page. It can sleep, and it indicates success by using the page >>> flags. Don't try and scqueeze rw_bytes into it. If you want rw_bytes >>> to be a queue operation, that's one thing, but don't mess with rw_page. >> >> Oh, I forgot about the page manipulating nature. Yes, we'll need a different >> operation in this case. > > I didn't see this addressed in the new patch set. I'm also concerned > about the layering, but I haven't put enough time into it to really make > a better suggestion. I really dislike the idea of yet another device > stacking model in the kernel and I'm worried the code will go in, and the > sysfs interface will end up as a "user abi" and we won't be able to > change it in the future. > > Dan, have you made any progress on this, or do you have plans to? ? in v6 ->rw_bytes() moved from libnvdimm local hackery to a top-level block device operation. Is that your concern or something else?