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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	b.a.t.m.a.n@lists.open-mesh.org,
	Akinobu Mita <akinobu.mita@gmail.com>,
	Simon Wunderlich <siwu@hrz.tu-chemnitz.de>,
	netdev@vger.kernel.org, Marek Lindner <lindner_marek@yahoo.de>,
	"David S. Miller" <davem@davemloft.net>,
	alan@lxorguk.ukuu.org.uk
Subject: [B.A.T.M.A.N.] [ 57/80] batman-adv: fix random jitter calculation
Date: Wed,  9 Jan 2013 12:35:49 -0800	[thread overview]
Message-ID: <20130109201507.762332404@linuxfoundation.org> (raw)
In-Reply-To: <20130109201500.410171651@linuxfoundation.org>

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Akinobu Mita <akinobu.mita@gmail.com>

[ 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 <akinobu.mita@gmail.com>
Acked-by: Antonio Quartulli <ordex@autistici.org>
Cc: Marek Lindner <lindner_marek@yahoo.de>
Cc: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Cc: Antonio Quartulli <ordex@autistici.org>
Cc: b.a.t.m.a.n@lists.open-mesh.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/batman-adv/bat_iv_ogm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -72,7 +72,7 @@ static unsigned long bat_iv_ogm_emit_sen
 {
 	return jiffies + msecs_to_jiffies(
 		   atomic_read(&bat_priv->orig_interval) -
-		   JITTER + (random32() % 2*JITTER));
+		   JITTER + (random32() % (2*JITTER)));
 }
 
 /* when do we schedule a ogm packet to be sent */



           reply	other threads:[~2013-01-09 20:35 UTC|newest]

Thread overview: expand[flat|nested]  mbox.gz  Atom feed
 [parent not found: <20130109201500.410171651@linuxfoundation.org>]

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