Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760244Ab2FGNUX (ORCPT ); Thu, 7 Jun 2012 09:20:23 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:59300 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757999Ab2FGNUV (ORCPT ); Thu, 7 Jun 2012 09:20:21 -0400 From: OGAWA Hirofumi To: Ingo Molnar , Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Andrew Morton , Steven Rostedt Subject: [PATCH] Use atomic_xchg() instead atomic_dec_and_test() for stop_machine Date: Thu, 07 Jun 2012 22:20:18 +0900 Message-ID: <87zk8fgsx9.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1413 Lines: 37 stop_machine_first is just to see if it is first one or not. In this usage, atomic_dec_and_test() makes value less than 0. I think it is not desirable, because it only triggers atomic_dec_and_test() less than 0 debug patch. (the patch tests result of atomic_dec_and_test() is < 0) So, this uses atomic_xchg() instead. Signed-off-by: OGAWA Hirofumi Acked-by: Steven Rostedt --- arch/x86/kernel/alternative.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN arch/x86/kernel/alternative.c~stop_machine-use-atomic_xchg arch/x86/kernel/alternative.c --- linux/arch/x86/kernel/alternative.c~stop_machine-use-atomic_xchg 2012-05-23 13:10:03.000000000 +0900 +++ linux-hirofumi/arch/x86/kernel/alternative.c 2012-05-23 13:10:03.000000000 +0900 @@ -664,7 +664,7 @@ static int __kprobes stop_machine_text_p struct text_poke_param *p; int i; - if (atomic_dec_and_test(&stop_machine_first)) { + if (atomic_xchg(&stop_machine_first, 0)) { for (i = 0; i < tpp->nparams; i++) { p = &tpp->params[i]; text_poke(p->addr, p->opcode, p->len); _ -- OGAWA Hirofumi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/