Re: [PATCHv2] bridge: disable snooping if there is no querier
From: Stephen Hemminger
Date: Thu Jul 25 2013 - 12:01:58 EST
On Thu, 25 Jul 2013 15:56:20 +0200
Linus Lüssing <linus.luessing@xxxxxx> 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);
}
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