From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753853AbcDNKDZ (ORCPT ); Thu, 14 Apr 2016 06:03:25 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:37517 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752002AbcDNKDG convert rfc822-to-8bit (ORCPT ); Thu, 14 Apr 2016 06:03:06 -0400 Subject: Re: [Question] refcount of DT node Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Content-Type: text/plain; charset=utf-8 From: Pantelis Antoniou In-Reply-To: <20160414095957.GB10273@leverpostej> Date: Thu, 14 Apr 2016 13:02:56 +0300 Cc: Russell King - ARM Linux , rank Rowand , Rob Herring , Masahiro Yamada , devicetree@vger.kernel.org, Arnd Bergmann , Linux Kernel Mailing List , linux-arm-kernel Content-Transfer-Encoding: 8BIT Message-Id: <06E9E2D3-4627-4970-ABBB-34B5ED620709@konsulko.com> References: <20160414084849.GT19428@n2100.arm.linux.org.uk> <20160414095957.GB10273@leverpostej> To: Mark Rutland X-Mailer: Apple Mail (2.3124) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, > On Apr 14, 2016, at 12:59 , Mark Rutland wrote: > > On Thu, Apr 14, 2016 at 09:48:49AM +0100, Russell King - ARM Linux wrote: >> On Thu, Apr 14, 2016 at 04:47:57PM +0900, Masahiro Yamada wrote: >>> Hi experts. >>> >>> My understanding of refcount of DT node is poor. >> >> The message from DT people is... don't worry about DT node refcounting. >> Do whatever you want with it, they don't care whether you have correct >> refcounting or not. >> >> The background behind that is that I've tried to fix the refcounting, >> and even had the coccinelle people generate some stuff to work on this >> issue, but DT people's attitude towards it is "don't bother". >> >> So yes, people may get it wrong, but it seems it's something that DT >> people want ignored. > > I'm not sure that's quite fair; the last discussion I recall about this > ended up concluding that we need a better API, rather than papering over > problems. > > That said, there isn't much obvious progress on that front. > > Frank, Pantelis, Rob, were there any conclusions on this from ELC, or is > this something that needs someone to propose something? > Frank mentioned that he wants a new API. I have some ideas about it too. My take is that drivers should never do reference counting, we have to figure out a way for DT access using copy semantics or locks. References would still be required for core DT code, but that’s a sane subset. > Mark. > > [1] http://permalink.gmane.org/gmane.linux.drivers.devicetree/153777 Regards — Pantelis