Re: [PATCHv2] bridge: disable snooping if there is no querier
From: Stephen Hemminger <stephen@networkplumber.org>
Date: 2013-07-25 16:01:47
Also in:
bridge, lkml
On Thu, 25 Jul 2013 15:56:20 +0200 Linus Lüssing [off-list ref] wrote:
+static void br_multicast_update_querier_timer(struct net_bridge *br,
+ unsigned long max_delay)
+{
+ if (!timer_pending(&br->multicast_querier_timer))
+ atomic64_set(&br->multicast_querier_delay_time,
+ jiffies + max_delay);
+
+ mod_timer(&br->multicast_querier_timer,
+ jiffies + br->multicast_querier_interval);
+}
+
Isn't this test racing with timer expiration.
static void br_multicast_update_querier_timer(struct net_bridge *br,
unsigned long max_delay)
{
if (!timer_pending(&br->multicast_querier_timer))
atomic64_set(&br->multicast_querier_delay_time,
jiffies + max_delay);
What if timer completes here?
mod_timer(&br->multicast_querier_timer,
jiffies + br->multicast_querier_interval);
}
And another race if timer goes off?
static void br_multicast_update_querier_timer(struct net_bridge *br,
unsigned long max_delay)
{
if (!timer_pending(&br->multicast_querier_timer))
atomic64_set(&br->multicast_querier_delay_time,
jiffies + max_delay);
Timer fires here...?
mod_timer(&br->multicast_querier_timer,
jiffies + br->multicast_querier_interval);
}