From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932991AbdBVR31 convert rfc822-to-8bit (ORCPT ); Wed, 22 Feb 2017 12:29:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46486 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932663AbdBVR3S (ORCPT ); Wed, 22 Feb 2017 12:29:18 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <2236FBA76BA1254E88B949DDB74E612B41C4EF59@IRSMSX102.ger.corp.intel.com> References: <2236FBA76BA1254E88B949DDB74E612B41C4EF59@IRSMSX102.ger.corp.intel.com> <1487691808-11289-2-git-send-email-elena.reshetova@intel.com> <1487691808-11289-1-git-send-email-elena.reshetova@intel.com> <12908.1487780160@warthog.procyon.org.uk> To: "Reshetova, Elena" Cc: dhowells@redhat.com, "linux-kernel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "peterz@infradead.org" , "gregkh@linuxfoundation.org" , Hans Liljestrand , "Kees Cook" , David Windsor Subject: Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <8876.1487784554.1@warthog.procyon.org.uk> Content-Transfer-Encoding: 8BIT Date: Wed, 22 Feb 2017 17:29:14 +0000 Message-ID: <8877.1487784554@warthog.procyon.org.uk> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 22 Feb 2017 17:29:18 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reshetova, Elena wrote: > Thank you very much David for testing the patches! > I guess for this one and other two patches it means that if we want to do the atomic_t --> refcount_t conversions, > we need to do +1 on the whole counting scheme to avoid issues around reaching zero. > Do you see this approach reasonable? I can give it a try, if it makes sense in your opinion. Or you could create a refcount_inc_may_resurrect() function that does allow increment from 0. Make it take a lock-check like the rcu functions do. David