From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 695A820958985 for ; Wed, 5 Jul 2017 19:09:40 -0700 (PDT) Date: Thu, 6 Jul 2017 04:11:18 +0200 From: "hch@lst.de" Subject: Re: [PATCH v4 12/16] libnvdimm, nfit: enable support for volatile ranges Message-ID: <20170706021118.GA14468@lst.de> References: <595580A6.9000004@hpe.com> <595589CF.5010605@hpe.com> <1499297819.2042.5.camel@hpe.com> <1499303324.2042.7.camel@hpe.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: "jack@suse.cz" , "mawilcox@microsoft.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-nvdimm@lists.01.org" , "viro@zeniv.linux.org.uk" , "linux-fsdevel@vger.kernel.org" , "hch@lst.de" List-ID: T24gV2VkLCBKdWwgMDUsIDIwMTcgYXQgMDc6MDg6NTRQTSAtMDcwMCwgRGFuIFdpbGxpYW1zIHdy b3RlOgo+IFsgYWRkaW5nIEplZmYsIGFuZCBKb2hhbm5lcyBdCj4gCj4gT24gV2VkLCBKdWwgNSwg MjAxNyBhdCA2OjE3IFBNLCBLYW5pLCBUb3NoaW1pdHN1IDx0b3NoaS5rYW5pQGhwZS5jb20+IHdy b3RlOgo+ID4gT24gV2VkLCAyMDE3LTA3LTA1IGF0IDE3OjA3IC0wNzAwLCBEYW4gV2lsbGlhbXMg d3JvdGU6Cj4gWy4uXQo+ID4+IFdlIGhhdmUgc3ltbGlua3MgaW4gL2Rldi9kaXNrL2J5KiB0byBt YWtlIGl0IGVhc2llciB0byBpZGVudGlmeQo+ID4+IHN0b3JhZ2UgZGV2aWNlcywgSSB0aGluayBp dCBtYWtlcyBzZW5zZSB0byBhZGQgdWRldiBydWxlcyBmb3IKPiA+PiBpZGVudGlmeWluZyB2b2xh dGlsZSBwbWVtIGFuZCBub3QgdHJ5IHRvIGRpZmZlcmVudGlhdGUgdGhpcyBpbiB0aGUKPiA+PiBk ZWZhdWx0IGtlcm5lbCBkZXZpY2UgbmFtZS4KPiA+Cj4gPiBJIGFtIG5vdCBzdXJlIHdoYXQgbWln aHQgYmUgYSBnb29kIHdheSwgYnV0IEkgYW0gY29uY2VybmVkIGJlY2F1c2UgYQo+ID4gc2luZ2xl IGJsb2NrIGRldmljZSBuYW1pbmcgZG8gbm90IHJlcHJlc2VudCBib3RoIHZvbGF0aWxlIGFuZAo+ ID4gcGVyc2lzdGVudCBtZWRpYSB0b2RheS4KPiAKPiBXZSBkbyBoYXZlIHRpbWUgdG8gY2hhbmdl cyB0aGlzIGlmIHdlIGZpbmQgb3V0IHRoaXMgaXMgY3JpdGljYWwuIE1heWJlCj4gaXQncyBiZXN0 IHRvIGFzayBMaW51eCBkaXN0cm8gZm9sa3Mgd2hhdCB3b3VsZCBiZSBlYXNpZXIgZm9yIHRoZW0/ CgpJJ20gbm90IHJlYWxseSBjb25jZXJuZWQgYWJvdXQgaXQsIGJlY2F1c2UgU0NTSSBkZXZpY2Vz IGZvciBleGFtcGxlCm1pZ2h0IG5vdCBiZSBwZXJzaXN0ZW50IGFzIHdlbGwgd2l0aCDRlWNzaV9k ZWJ1ZywgdGFyZ2V0X2NvcmVfcmQgb3IKdm9sYXRpbGUgcWVtdSBkZXZpY2VzLgoKVGhhdCBiZWlu ZyBzYWlkIEkgcmVhbGx5IGRvbid0IHVuZGVyc3RhbmQgdGhlIHB1cnBvc2Ugb2YgdGhlc2Ugdm9s YXRpbGUKbmZpdCByYW5nZXMuICBBcmUgdGhleSBzZWVuIGluIHRoZSB3aWxkPyAgSWYgeWVzIHdo YXQncyB0aGUgdXNlIGNhc2U/CklmIG5vdCB3aHkgZG8gd2UgZXZlbiBuZWVkIHRvIHN1cHBvcnQg dGhlbT8KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KTGlu dXgtbnZkaW1tIG1haWxpbmcgbGlzdApMaW51eC1udmRpbW1AbGlzdHMuMDEub3JnCmh0dHBzOi8v bGlzdHMuMDEub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgtbnZkaW1tCg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752663AbdGFCLV (ORCPT ); Wed, 5 Jul 2017 22:11:21 -0400 Received: from verein.lst.de ([213.95.11.211]:57569 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751914AbdGFCLU (ORCPT ); Wed, 5 Jul 2017 22:11:20 -0400 Date: Thu, 6 Jul 2017 04:11:18 +0200 From: "hch@lst.de" To: Dan Williams Cc: "Kani, Toshimitsu" , "linux-kernel@vger.kernel.org" , "hch@lst.de" , "viro@zeniv.linux.org.uk" , "x86@kernel.org" , "mawilcox@microsoft.com" , "linux-nvdimm@lists.01.org" , "Knippers, Linda" , "linux-fsdevel@vger.kernel.org" , "jack@suse.cz" , jmoyer , Johannes Thumshirn Subject: Re: [PATCH v4 12/16] libnvdimm, nfit: enable support for volatile ranges Message-ID: <20170706021118.GA14468@lst.de> References: <595580A6.9000004@hpe.com> <595589CF.5010605@hpe.com> <1499297819.2042.5.camel@hpe.com> <1499303324.2042.7.camel@hpe.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 05, 2017 at 07:08:54PM -0700, Dan Williams wrote: > [ adding Jeff, and Johannes ] > > On Wed, Jul 5, 2017 at 6:17 PM, Kani, Toshimitsu wrote: > > On Wed, 2017-07-05 at 17:07 -0700, Dan Williams wrote: > [..] > >> We have symlinks in /dev/disk/by* to make it easier to identify > >> storage devices, I think it makes sense to add udev rules for > >> identifying volatile pmem and not try to differentiate this in the > >> default kernel device name. > > > > I am not sure what might be a good way, but I am concerned because a > > single block device naming do not represent both volatile and > > persistent media today. > > We do have time to changes this if we find out this is critical. Maybe > it's best to ask Linux distro folks what would be easier for them? I'm not really concerned about it, because SCSI devices for example might not be persistent as well with ѕcsi_debug, target_core_rd or volatile qemu devices. That being said I really don't understand the purpose of these volatile nfit ranges. Are they seen in the wild? If yes what's the use case? If not why do we even need to support them?