Use of IRQF_DISABLED along with IRQF_SHARED

[Rajat Jain]

Hi,

This is regarding the following code in kernel/irq/handle.c. Consider the case 
of a shared IRQ line, where two handlers are registered such that first handler 
does not specify IRQF_DISABLED, but the second one does. But it seems both the 
handlers will be called IRQs ENABLED (which is certainly not what the second 
handler expects). 

I also checked but could not find anything that stops me from registering two 
shared ISRs - one with IRQF_DISABLED & another without this flag. Am I missing 
something here?

irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
{
    irqreturn_t ret, retval = IRQ_NONE;
    unsigned int status = 0;

    handle_dynamic_tick(action);

    if (!(action->flags & IRQF_DISABLED))
        local_irq_enable_in_hardirq();

    do {
        ret = action->handler(irq, action->dev_id);
        if (ret == IRQ_HANDLED)
            status |= action->flags;
        retval |= ret;
        action = action->next;
    } while (action);

    if (status & IRQF_SAMPLE_RANDOM)
        add_interrupt_randomness(irq);
    local_irq_disable();

    return retval;
}

Thanks,

Rajat
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