* [ 57/80] batman-adv: fix random jitter calculation
[not found] <20130109201500.410171651@linuxfoundation.org>
@ 2013-01-09 20:35 ` Greg Kroah-Hartman
0 siblings, 0 replies; only message in thread
From: Greg Kroah-Hartman @ 2013-01-09 20:35 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Greg Kroah-Hartman, alan, Akinobu Mita, Antonio Quartulli,
Marek Lindner, Simon Wunderlich, David S. Miller, b.a.t.m.a.n,
netdev
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 */
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