Re: [PATCH] serial: imx: drop workaround for forced irq threading

From: Sebastian Andrzej Siewior
Date: Mon Mar 22 2021 - 07:40:19 EST


On 2021-03-22 12:34:02 [+0100], Uwe Kleine-König wrote:
> On Mon, Mar 22, 2021 at 12:10:36PM +0100, Johan Hovold wrote:
> > Force-threaded interrupt handlers used to run with interrupts enabled,
> > something which could lead to deadlocks in case a threaded handler
> > shared a lock with code running in hard interrupt context (e.g. timer
> > callbacks) and did not explicitly disable interrupts.
> >
> > This was specifically the case for serial drivers that take the port
> > lock in their console write path as printk can be called from hard
> > interrupt context also with forced threading ("threadirqs").
> >
> > Since commit 81e2073c175b ("genirq: Disable interrupts for force
> > threaded handlers") interrupt handlers always run with interrupts
> > disabled on non-RT so that drivers no longer need to do handle this.
>
> So we're breaking RT knowingly here? If this is the case I'm not happy
> with your change. (And if RT is not affected a different wording would
> be good.)

Which wording, could you be more specific? It looks good from here and
no, RT is not affected.

> Best regards
> Uwe

Sebastian