[patch V2 10/11] netfilter: xt_IDLETIMER: Switch to alarm_start_timer()

Thomas Gleixner
2026-04-08T11:54:31Z

The existing alarm_start() interface is replaced with the new
alarm_start_timer() mechanism, which does not longer queue an already
expired timer and returns the state.

Adjust the code to utilize this so it schedules the work in the case that
the timer was already expired. Unlikely to happen as the timeout is at
least a second, but not impossible especially with virtualization.

No functional change intended

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>
Cc: Phil Sutter <phil@nwl.cc>
Cc: netfilter-devel@vger.kernel.org
Cc: coreteam@netfilter.org

---
net/netfilter/xt_IDLETIMER.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
--- a/net/netfilter/xt_IDLETIMER.c
+++ b/net/netfilter/xt_IDLETIMER.c
@@ -115,6 +115,21 @@ static void idletimer_tg_alarmproc(struc
schedule_work(&timer->work);
}

+static void idletimer_start_alarm_ktime(struct idletimer_tg *timer, ktime_t timeout)
+{
+ /*
+ * The timer should always be queued as @tout it should be least one
+ * second, but handle it correctly in any case. Virt will manage!
+ */
+ if (!alarm_start_timer(&timer->alarm, timeout, true))
+ schedule_work(&timer->work);
+}
+
+static void idletimer_start_alarm_sec(struct idletimer_tg *timer, unsigned int seconds)
+{
+ idletimer_start_alarm_ktime(timer, ktime_set(seconds, 0));
+}
+
static int idletimer_check_sysfs_name(const char *name, unsigned int size)
{
int ret;
@@ -220,12 +235,10 @@ static int idletimer_tg_create_v1(struct
INIT_WORK(&info->timer->work, idletimer_tg_work);

if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
- ktime_t tout;
alarm_init(&info->timer->alarm, ALARM_BOOTTIME,
idletimer_tg_alarmproc);
info->timer->alarm.data = info->timer;
- tout = ktime_set(info->timeout, 0);
- alarm_start_relative(&info->timer->alarm, tout);
+ idletimer_start_alarm_sec(info->timer, info->timeout);
} else {
timer_setup(&info->timer->timer, idletimer_tg_expired, 0);
mod_timer(&info->timer->timer,
@@ -271,8 +284,7 @@ static unsigned int idletimer_tg_target_
info->label, info->timeout);

if (info->timer->timer_type & XT_IDLETIMER_ALARM) {
- ktime_t tout = ktime_set(info->timeout, 0);
- alarm_start_relative(&info->timer->alarm, tout);
+ idletimer_start_alarm_sec(info->timer, info->timeout);
} else {
mod_timer(&info->timer->timer,
secs_to_jiffies(info->timeout) + jiffies);
@@ -378,7 +390,7 @@ static int idletimer_tg_checkentry_v1(co
if (ktimespec.tv_sec > 0) {
pr_debug("time_expiry_remaining %lld\n",
ktimespec.tv_sec);
- alarm_start_relative(&info->timer->alarm, tout);
+ idletimer_start_alarm_ktime(info->timer, tout);
}
} else {
mod_timer(&info->timer->timer,