Re: [Linuxarm] Re: [PATCH for next v1 1/2] gpio: omap: Replace raw_spin_lock_irqsave with raw_spin_lock in omap_gpio_irq_handler()

Arnd Bergmann
2021-02-12T09:46:26Z

On Fri, Feb 12, 2021 at 6:05 AM Song Bao Hua (Barry Song)
<song.bao.hua@hisilicon.com> wrote:
> > -----Original Message-----

> >
> > Note. there is also generic_handle_irq() call inside.
>
> So generic_handle_irq() is not safe to run in thread thus requires
> an interrupt-disabled environment to run? If so, I'd rather this
> irqsave moved into generic_handle_irq() rather than asking everyone
> calling it to do irqsave.

In a preempt-rt kernel, interrupts are run in task context, so they clearly
should not be called with interrupts disabled, that would defeat the
purpose of making them preemptible.

generic_handle_irq() does need to run with in_irq()==true though,
but this should be set by the caller of the gpiochip's handler, and
it is not set by raw_spin_lock_irqsave().

Arnd