| From 9d4265cdd6c161d51b37bb9c6b9a32ab164f72ff Mon Sep 17 00:00:00 2001 |
| From: Akinobu Mita <akinobu.mita@gmail.com> |
| Date: Wed, 26 Dec 2012 02:32:10 +0000 |
| Subject: batman-adv: fix random jitter calculation |
| |
| |
| 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 |
| @@ -119,7 +119,7 @@ batadv_iv_ogm_emit_send_time(const struc |
| 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); |
| } |