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

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Message-ID: <al63ckh4mhr24yony4paeuegh5m3nir77ymkx25okbzvazmghh@avpbc2lsejle>
Date: Sat, 24 Jan 2026 21:30:07 -0800
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Thomas Gleixner <tglx@...nel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>, 
	Marek Vasut <marek.vasut+renesas@...lbox.org>, linux-input@...r.kernel.org, 
	"Peter Zijlstra (Intel)" <peterz@...radead.org>, Cheng-Yang Chou <yphbchou0911@...il.com>, 
	Frank Li <Frank.Li@....com>, Geert Uytterhoeven <geert+renesas@...der.be>, 
	Jinjie Ruan <ruanjinjie@...wei.com>, Krzysztof Kozlowski <krzysztof.kozlowski@....qualcomm.com>, 
	Marc Zyngier <maz@...nel.org>, linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH 1/2] linux/interrupt.h: allow "guard" notation to disable
 and reenable IRQ with valid IRQ check

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