Re: [patch V2 26/45] genirq/chip: Rework irq_set_handler() variants

Nathan Chancellor
2025-05-09T13:22:15Z

Hi Thomas,

On Tue, Apr 29, 2025 at 08:55:26AM +0200, Thomas Gleixner wrote:
> Use the new guards to get and lock the interrupt descriptor and tidy up the
> code.
>
> Fixup the kernel doc comment while at it.
>
> No functional change.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>
> ---
> kernel/irq/chip.c | 34 +++++++++++-----------------------
> 1 file changed, 11 insertions(+), 23 deletions(-)
>
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -973,35 +973,23 @@ static void
> }
> }
>
> -void
> -__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
> - const char *name)
> +void __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
> + const char *name)
> {
> - unsigned long flags;
> - struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
> -
> - if (!desc)
> - return;
> -
> - __irq_do_set_handler(desc, handle, is_chained, name);
> - irq_put_desc_busunlock(desc, flags);
> + scoped_irqdesc_get_and_lock(irq, 0)

I am investigating some cases where

WARN(!irqs_disabled(), "Interrupts were enabled early\n");

in start_kernel() in init/main.c is triggered in certain builds with
clang after patch 23 of this series (very bizarre since the conversion
seems to be correct) and I happened to notice that this conversion seems
to be incorrect? Should this be scoped_irqdesc_get_and_buslock() like
below?

> + __irq_do_set_handler(scoped_irqdesc, handle, is_chained, name);
> }
> EXPORT_SYMBOL_GPL(__irq_set_handler);
>
> -void
> -irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
> - void *data)
> +void irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
> + void *data)
> {
> - unsigned long flags;
> - struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
> -
> - if (!desc)
> - return;
> + scoped_irqdesc_get_and_buslock(irq, 0) {
> + struct irq_desc *desc = scoped_irqdesc;
>
> - desc->irq_common_data.handler_data = data;
> - __irq_do_set_handler(desc, handle, 1, NULL);
> -
> - irq_put_desc_busunlock(desc, flags);
> + desc->irq_common_data.handler_data = data;
> + __irq_do_set_handler(desc, handle, 1, NULL);
> + }
> }
> EXPORT_SYMBOL_GPL(irq_set_chained_handler_and_data);
>
>
>
>