From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH 02/86] batman-adv: fix random jitter calculation Date: Tue, 26 Mar 2013 13:21:01 -0400 Message-ID: <20130326173600.211530324@goodmis.org> References: <20130326172059.136127374@goodmis.org> Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, b.a.t.m.a.n-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org, Akinobu Mita , Simon Wunderlich , Marek Lindner , "David S. Miller" To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: Content-Disposition: inline; filename=0002-batman-adv-fix-random-jitter-calculation.patch List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: b.a.t.m.a.n-bounces-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org Sender: "B.A.T.M.A.N" List-Id: netdev.vger.kernel.org 3.6.11.1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Akinobu Mita [ Upstream commit 143cdd8f33909ff5a153e3f02048738c5964ba26 ] 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-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org Cc: "David S. Miller" Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Signed-off-by: David S. Miller --- 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 469daab..1476f26 100644 --- a/net/batman-adv/bat_iv_ogm.c +++ b/net/batman-adv/bat_iv_ogm.c @@ -119,7 +119,7 @@ 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); } -- 1.7.10.4