From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751707AbcFWUsb (ORCPT ); Thu, 23 Jun 2016 16:48:31 -0400 Received: from mail.fireflyinternet.com ([87.106.93.118]:57882 "EHLO fireflyinternet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751063AbcFWUsa (ORCPT ); Thu, 23 Jun 2016 16:48:30 -0400 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Date: Thu, 23 Jun 2016 21:48:14 +0100 From: Chris Wilson To: Gustavo Padovan Cc: dri-devel@lists.freedesktop.org, marcheu@google.com, Daniel Stone , seanpaul@google.com, Daniel Vetter , linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com, Gustavo Padovan , John Harrison , m.chehab@samsung.com Subject: Re: [RFC 1/5] dma-buf/fence: add .teardown() ops Message-ID: <20160623204814.GC1086@nuc-i3427.alporthouse.com> Mail-Followup-To: Chris Wilson , Gustavo Padovan , dri-devel@lists.freedesktop.org, marcheu@google.com, Daniel Stone , seanpaul@google.com, Daniel Vetter , linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com, Gustavo Padovan , John Harrison , m.chehab@samsung.com References: <1466695790-2833-1-git-send-email-gustavo@padovan.org> <1466695790-2833-2-git-send-email-gustavo@padovan.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1466695790-2833-2-git-send-email-gustavo@padovan.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 23, 2016 at 12:29:46PM -0300, Gustavo Padovan wrote: > From: Gustavo Padovan > > fence_array requires a function to clean up its state before we > are able to call fence_put() and release it. An explanation along the lines of: As the array of fence callbacks held by an active struct fence_array each has a reference to the struct fence_array, when the owner of the fence_array is freed it must dispose of the callback references before it can free the fence_array. This can not happen simply during fence_release() because of the extra references and so we need a new function to run before the final fence_put(). would help, it is not until you use it in 5/5 that it becomes apparent why it is needed. -Chris -- Chris Wilson, Intel Open Source Technology Centre