The "handle_arch_irq" function pointer is assigned in 2 places with interrupt handler.

1st place:

void setup_arch()
{
    handle_arch_irq = mdesc->handle_irq;
}

2nd place:

int set_handle_irq()
{
    handle_arch_irq = handle_irq;
}

The set_handle_irq() is called from irq-gic.c.

Can you help to understand why we are initializing at two places.