From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756125AbcCQMDC (ORCPT ); Thu, 17 Mar 2016 08:03:02 -0400 Received: from www.linutronix.de ([62.245.132.108]:59821 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753700AbcCQMDA (ORCPT ); Thu, 17 Mar 2016 08:03:00 -0400 Date: Thu, 17 Mar 2016 13:01:32 +0100 (CET) From: Thomas Gleixner To: Peter Zijlstra cc: Xiong Zhou , "linux-kernel@vger.kernel.org" , Ingo Molnar , Borislav Petkov , Andreas Herrmann , Jens Axboe Subject: Re: 4.5.0+ panic when setup loop device In-Reply-To: <20160317115120.GT6344@twins.programming.kicks-ass.net> Message-ID: References: <20160317095220.GO6344@twins.programming.kicks-ass.net> <20160317102633.GR6344@twins.programming.kicks-ass.net> <20160317115120.GT6344@twins.programming.kicks-ass.net> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 17 Mar 2016, Peter Zijlstra wrote: > On Thu, Mar 17, 2016 at 12:39:46PM +0100, Thomas Gleixner wrote: > > But we have to clarify and document whether holes in cpu_possible_mask are not > > allowed at all or if code like the above is simply broken. > > So the general rule is that cpumasks can have holes, and exempting one > just muddles the water. > > Therefore I'd call the code just plain broken. Agreed. That macro is not really helping the readability of the code at all. So a simple for_each_possible_cpu() loop would have avoided that wreckage. Thanks, tglx