Work queue: What will happen if same work is queued twice?

> Hi,
>
> I have a single work queue, on which I have scheduled a worker function [using queue_work(wq, fn)] in interrupt context.
>
> I get the interrupt twice before the work queue gets a chance to run, and hence the same function will get queued twice (with different private context - arguments etc) which is fine and expected.

You got it wrong here.

bool queue_work_on(int cpu, struct workqueue_struct *wq,
                   struct work_struct *work)
{
        bool ret = false;
        unsigned long flags;

        local_irq_save(flags);

        if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
                __queue_work(cpu, wq, work);
                ret = true;
        }

        local_irq_restore(flags);
        return ret;
}
EXPORT_SYMBOL(queue_work_on);

If you look at function queue_work_on, the function returns
immediately if WORK_STRUCT_PENDING_BIT was already set.
So in effect your second call to queue_work will just return.

HTH

Thanks,
Arun