Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935220AbcJQOsx (ORCPT ); Mon, 17 Oct 2016 10:48:53 -0400 Received: from foss.arm.com ([217.140.101.70]:35360 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933390AbcJQOsp (ORCPT ); Mon, 17 Oct 2016 10:48:45 -0400 Date: Mon, 17 Oct 2016 15:48:13 +0100 From: Mark Rutland To: Heiko Carstens Cc: Andy Lutomirski , Peter Zijlstra , Linus Torvalds , Ingo Molnar , "H . Peter Anvin" , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Schwidefsky Subject: Re: [PATCH] thread_info: include for THREAD_INFO_IN_TASK (WAS: [PATCH 2/3] sched/preempt: include asm/current.h) Message-ID: <20161017144700.GA11204@leverpostej> References: <20161014081638.GA4047@osiris> <1476441745-10765-1-git-send-email-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1476441745-10765-1-git-send-email-mark.rutland@arm.com> 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 Content-Length: 1870 Lines: 52 On Fri, Oct 14, 2016 at 11:42:25AM +0100, Mark Rutland wrote: > When CONFIG_THREAD_INFO_IN_TASK is selected, the current_thread_info() > macro relies on current having been defined prior to its use. However, > not all users of current_thread_info() include , and thus > current is not guaranteed to be defined. > > When CONFIG_THREAD_INFO_IN_TASK is not selected, it's possible that > get_current() / current are based upon current_thread_info(), and > includes . Thus always including > would result in circular dependences on some platforms. > > To ensure both cases work, this patch includes , but only > when CONFIG_THREAD_INFO_IN_TASK is selected. > > Signed-off-by: Mark Rutland > --- > include/linux/thread_info.h | 1 + > 1 file changed, 1 insertion(+) > > As discussed, it would be great if this could go in along with the patch to > make thread_info arch-specific again, to make merging the arch-specific parts > easier (for arm64 and s390). Urrgh; I've just recalled that this patch alone is insufficient. The h8300 arch code has an unfixed bug [1], and relies on some implicit definition ordering that will be broken by this patch. I have a workaround/cleanup for core code that I'll send with an updated version of my arm64 series shortly. Thanks, Mark. [1] http://lkml.kernel.org/r/<1476714934-11635-1-git-send-email-mark.rutland@arm.com > Mark. > > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h > index 45f004e..521f84b 100644 > --- a/include/linux/thread_info.h > +++ b/include/linux/thread_info.h > @@ -25,6 +25,7 @@ struct thread_info { > #endif > > #ifdef CONFIG_THREAD_INFO_IN_TASK > +#include > #define current_thread_info() ((struct thread_info *)current) > #endif > > -- > 1.9.1 >