Re: [PATCH 1/2] linux/interrupt.h: allow "guard" notation to disable and reenable IRQ with valid IRQ check

[Dmitry Torokhov]

Hi Thomas,

On Fri, Jan 23, 2026 at 11:52:58AM +0100, Thomas Gleixner wrote:
> On Thu, Jan 22 2026 at 17:22, Sebastian Andrzej Siewior wrote:
> 
> > On 2026-01-22 00:23:47 [+0100], Marek Vasut wrote:
> >> @@ -242,6 +242,21 @@ extern void irq_wake_thread(unsigned int irq, void *dev_id);
> >>  DEFINE_LOCK_GUARD_1(disable_irq, int,
> >>  		    disable_irq(*_T->lock), enable_irq(*_T->lock))
> >>  
> >> +static inline void disable_valid_irq(unsigned int irq)
> >> +{
> >> +	if (irq > 0)
> >> +		disable_irq(irq);
> >> +}
> >
> > | $ grep " 0:" /proc/interrupts
> > |    0:         43          0          IO-APIC  2-edge      timer
> >
> > in other words, interrupt 0 is valid.
> 
> No. It's not really.
> 
> Interrupt number zero is a historic leftover and a mistake which is only
> relevant to some oddball archaic architectures like x86 and others which
> tried to mimic that.
> 
> The general agreement is that interrupt 0 is a legacy oddity and only
> supported in very special cases. Everything else treats 0 as invalid.

Could you ack this new guard if you agree with it please?

Thanks.

-- 
Dmitry