Re: [PATCH 16/21] perf/cxlpmu: Replace IRQF_ONESHOT with IRQF_NO_THREAD

Jonathan Cameron
2026-01-23T12:05:21Z

On Fri, 23 Jan 2026 12:37:02 +0100
Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> Passing IRQF_ONESHOT ensures that the interrupt source is masked until
> the secondary (threaded) handler is done. If only a primary handler is
> used then the flag makes no sense because the interrupt can not fire
> (again) while its handler is running.
> The flag also disallows force-threading of the primary handler and the
> irq-core will warn about this.
>
> The intention here was probably not allowing forced-threading.
>
> Replace IRQF_ONESHOT with IRQF_NO_THREAD.
>
I don't think we are that likely to see force-threading on CXL
systems (I could be wrong!), but still good to correct this.

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: linux-cxl@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
> drivers/perf/cxl_pmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/perf/cxl_pmu.c b/drivers/perf/cxl_pmu.c
> index d094030220bf2..68a54d97d2a8a 100644
> --- a/drivers/perf/cxl_pmu.c
> +++ b/drivers/perf/cxl_pmu.c
> @@ -877,7 +877,7 @@ static int cxl_pmu_probe(struct device *dev)
> if (!irq_name)
> return -ENOMEM;
>
> - rc = devm_request_irq(dev, irq, cxl_pmu_irq, IRQF_SHARED | IRQF_ONESHOT,
> + rc = devm_request_irq(dev, irq, cxl_pmu_irq, IRQF_SHARED | IRQF_NO_THREAD,
> irq_name, info);
> if (rc)
> return rc;