On Mon, Dec 21, 2015 at 11:15 AM, Richard Cochran
[off-list ref] wrote:

On Sun, Dec 20, 2015 at 11:46:30PM +0200, Saeed Mahameed wrote:

quoted

+/* Should run once every mlx5e_tstamp->overflow_period */
+static void mlx5e_timestamp_overflow(struct work_struct *work)
+{
+     struct delayed_work *dwork = to_delayed_work(work);
+     struct mlx5e_tstamp *tstamp = container_of(dwork, struct mlx5e_tstamp, overflow_work);
+     unsigned long flags;
+
+     write_lock_irqsave(&tstamp->lock, flags);
+     timecounter_read(&tstamp->clock);
+     if (tstamp->overflow_period)
+             schedule_delayed_work(&tstamp->overflow_work, tstamp->overflow_period);

You don't need this test, and the call to schedule_delayed_work can be
outside of the lock.

Ok, but what will happen if somehow tstamp->overflow_period is zero ?
the work will run too rapidly.
don't we need to have protection against such case.