[57/80] batman-adv: fix random jitter calculation

Submitted by Greg KH on Jan. 9, 2013, 8:35 p.m.


Message ID 20130109201507.762332404@linuxfoundation.org
State Not Applicable
Delegated to: David Miller
Headers show

Commit Message

Greg KH Jan. 9, 2013, 8:35 p.m.
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

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(-)

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--- 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 */