Re: [PATCH rc v6 3/7] iommu/arm-smmu-v3: Do not enable EVTQ/PRIQ interrupts in kdump kernel

[Pranjal Shrivastava <praan@google.com>]

On Tue, Jun 30, 2026 at 04:58:14AM +0000, Pranjal Shrivastava wrote:
> On Mon, Jun 29, 2026 at 09:14:48PM -0700, Nicolin Chen wrote:
> > On Mon, Jun 29, 2026 at 08:48:11AM +0000, Pranjal Shrivastava wrote:
> > > On Wed, May 20, 2026 at 10:03:20AM -0700, Nicolin Chen wrote:
> > > > @@ -5020,19 +5029,30 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
> > > >  		/*
> > > >  		 * Cavium ThunderX2 implementation doesn't support unique irq
> > > >  		 * lines. Use a single irq line for all the SMMUv3 interrupts.
> > > > +		 *
> > > > +		 * In kdump, EVTQ/PRIQ are disabled, so no threaded handling.
> > > >  		 */
> > > > -		ret = devm_request_threaded_irq(smmu->dev, irq,
> > > > -					arm_smmu_combined_irq_handler,
> > > > -					arm_smmu_combined_irq_thread,
> > > > -					IRQF_ONESHOT,
> > > > -					"arm-smmu-v3-combined-irq", smmu);
> > > > +		if (is_kdump_kernel())
> > > > +			ret = devm_request_irq(smmu->dev, irq,
> > > > +					       arm_smmu_combined_irq_handler, 0,
> > > > +					       "arm-smmu-v3-combined-irq",
> > > > +					       smmu);
> > > 
> > 
> > Are you sure?
> > 
> > __setup_irq():
> > 1497-   /*
> > 1498:    * IRQF_ONESHOT means the interrupt source in the IRQ chip will be
> > 1499-    * masked until the threaded handled is done. If there is no thread
> > 1500:    * handler then it makes no sense to have IRQF_ONESHOT.
> > 1501-    */
> > 1502:   WARN_ON_ONCE(new->flags & IRQF_ONESHOT && !new->thread_fn);
> 
> I meant without IRQF_ONESHOT: 
> 
> is_kdump_kernel() ? 0 : IRQF_ONESHOT, note that devm_request_irq is just:
> 
> static inline int __must_check
> devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
> 		 unsigned long irqflags, const char *devname, void *dev_id)
> {
> 	return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags | IRQF_COND_ONESHOT,
> 					 devname, dev_id);
> }
> 
> Not a strong opinion though, just suggesting a way to remove the if.
> 

I though I had given an R-b earlier, but I didn't.
With that nit:
Reviewed-by: Pranjal Shrivastava <praan@google.com>

Thanks,
Praan