From patchwork Wed Dec 26 12:32:10 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akinobu Mita X-Patchwork-Id: 208166 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 328612C008E for ; Wed, 26 Dec 2012 23:32:58 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754427Ab2LZMcs (ORCPT ); Wed, 26 Dec 2012 07:32:48 -0500 Received: from mail-pa0-f41.google.com ([209.85.220.41]:52067 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754377Ab2LZMcq (ORCPT ); Wed, 26 Dec 2012 07:32:46 -0500 Received: by mail-pa0-f41.google.com with SMTP id bj3so4935268pad.28 for ; Wed, 26 Dec 2012 04:32:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer; bh=ZTZ3G+aRIvWo79PbthqMSUT3X64O7FssrGgXr66FW/M=; b=r6Q7iKbvXJcp6/xAiLTFfRT1wr6gk/DgdyifyCMKLjqLWpopvsxWE5tffgds0265gR bDd6s7MwUUW8kTkKvblDQ4H+CYDyBnvRPnp0oPBjOuis/aovpsTG10dzxKuGmi3gNPdH Uvx3puP5ySNdrJBqIaoquCMQ/4Nnv+BCTeIC1h9Xpl29XWL5fVGERkodbYbKCjK8X3aC mSqy3C7Oq/80Xo5VJnhfV5M0AXOm88ZQZTEM6Dw93BWroivfeFE1zVUInKDdMSAHG9Cs av0RlGC96cNSJbK4PtA7PmgxAH9lEn2cl3YudSFHwPM+h3b4wETiuosUPhMeCt7Tit6K p7YA== X-Received: by 10.68.253.230 with SMTP id ad6mr85952241pbd.84.1356525166310; Wed, 26 Dec 2012 04:32:46 -0800 (PST) Received: from localhost.localdomain (p2126-ipbf3106hodogaya.kanagawa.ocn.ne.jp. [114.149.157.126]) by mx.google.com with ESMTPS id ty4sm15845652pbc.57.2012.12.26.04.32.43 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 26 Dec 2012 04:32:45 -0800 (PST) From: Akinobu Mita To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: Akinobu Mita , Marek Lindner , Simon Wunderlich , Antonio Quartulli , b.a.t.m.a.n@lists.open-mesh.org, "David S. Miller" Subject: [PATCH] batman-adv: fix random jitter calculation Date: Wed, 26 Dec 2012 21:32:10 +0900 Message-Id: <1356525130-2688-1-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.7.11.7 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org batadv_iv_ogm_emit_send_time() attempts to calculates a random integer in the range of 'orig_interval +- BATADV_JITTER' by the below lines. msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER; msecs += (random32() % 2 * BATADV_JITTER); But it actually gets 'orig_interval' or 'orig_interval - BATADV_JITTER' because '%' and '*' have same precedence and associativity is left-to-right. This adds the parentheses at the appropriate position so that it matches original intension. Signed-off-by: Akinobu Mita Acked-by: Antonio Quartulli Cc: Marek Lindner Cc: Simon Wunderlich Cc: Antonio Quartulli Cc: b.a.t.m.a.n@lists.open-mesh.org Cc: "David S. Miller" Cc: netdev@vger.kernel.org --- This patch is extracted from the patch series "rename random32 and net_random to prandom" since it is a fix. net/batman-adv/bat_iv_ogm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c index 9f3925a..7d02ebd 100644 --- a/net/batman-adv/bat_iv_ogm.c +++ b/net/batman-adv/bat_iv_ogm.c @@ -123,7 +123,7 @@ batadv_iv_ogm_emit_send_time(const struct batadv_priv *bat_priv) unsigned int msecs; msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER; - msecs += (random32() % 2 * BATADV_JITTER); + msecs += random32() % (2 * BATADV_JITTER); return jiffies + msecs_to_jiffies(msecs); }