Re: [PATCH v2 4/6] genirq/test: Depend on SPARSE_IRQ

[David Gow]

On Sat, 23 Aug 2025 at 03:01, Brian Norris <briannorris@xxxxxxxxxxxx> wrote:
>
> Some architectures have a rather static IRQ layout, with a limited
> NR_IRQS. Without SPARSE_IRQ, we may not be able to allocate any new fake
> IRQs, and the test will fail. (This occurs on ARCH=m68k, for example.)
>
> Additionally, managed-affinity is only supported with
> CONFIG_SPARSE_IRQ=y, so irq_shutdown_depth_test() and
> irq_cpuhotplug_test() would fail without it.
>
> Add a 'SPARSE_IRQ' dependency to avoid these problems.
>
> Many architectures 'select SPARSE_IRQ', so this is easy to miss.
>
> Notably, this also excludes ARCH=um from running any of these tests,
> even though some of them might work.
>
> Fixes: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> ---

I confess to being disappointed that we lose ARCH=um support with this
-- it's nice to have it run on the "default" configuration -- but the
correct way of solving this is probably to support SPARSE_IRQ on UML,
which is probably more work than it's worth.

So this is, nevertheless,
Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

Cheers,
-- David

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