Function irq_chip::irq_request_resources() is reported as optional
in the declaration of struct irq_chip.
If the parent irq_chip does not implement it, we should ignore it
and return.

Don't return error if the functions is missing.

Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
---

As follow-up of discussion in
https://lore.kernel.org/lkml/875ymd6xdu.wl-maz@kernel.org/
here is a proposal for changing the returned value.

A similar issue is present for the optional function
irq_set_vcpu_affinity(), to be covered separately, if needed.

---
 kernel/irq/chip.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 54af0deb239b..eb921485930f 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1513,7 +1513,8 @@ int irq_chip_request_resources_parent(struct irq_data *data)
 	if (data->chip->irq_request_resources)
 		return data->chip->irq_request_resources(data);
 
-	return -ENOSYS;
+	/* no error on missing optional irq_chip::irq_request_resources */
+	return 0;
 }
 EXPORT_SYMBOL_GPL(irq_chip_request_resources_parent);
 

base-commit: c5eb0a61238dd6faf37f58c9ce61c9980aaffd7a
-- 
2.36.0

On Thu, 2022-05-12 at 18:05 +0200, Antonio Borneo wrote:
> Function irq_chip::irq_request_resources() is reported as optional
> in the declaration of struct irq_chip.
> If the parent irq_chip does not implement it, we should ignore it
> and return.
> 
> Don't return error if the functions is missing.
> 
> Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
> ---
> 
> As follow-up of discussion in
> https://lore.kernel.org/lkml/875ymd6xdu.wl-maz@kernel.org/
> here is a proposal for changing the returned value.
> 
> A similar issue is present for the optional function
> irq_set_vcpu_affinity(), to be covered separately, if needed.

Gentle ping for this patch.
Does it match the expected behaviour for an optional function?

Thanks,
Antonio


> 
> ---
>  kernel/irq/chip.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
> index 54af0deb239b..eb921485930f 100644
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -1513,7 +1513,8 @@ int irq_chip_request_resources_parent(struct
> irq_data *data)
>         if (data->chip->irq_request_resources)
>                 return data->chip->irq_request_resources(data);
>  
> -       return -ENOSYS;
> +       /* no error on missing optional
> irq_chip::irq_request_resources */
> +       return 0;
>  }
>  EXPORT_SYMBOL_GPL(irq_chip_request_resources_parent);
>  
> 
> base-commit: c5eb0a61238dd6faf37f58c9ce61c9980aaffd7a

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID:     95001b756467ecc9f5973eb5e74e97699d9bbdf1
Gitweb:        https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/95001b756467ecc9f5973eb5e74e97699d9bbdf1
Author:        Antonio Borneo <antonio.borneo@foss.st.com>
AuthorDate:    Thu, 12 May 2022 18:05:44 +02:00
Committer:     Marc Zyngier <maz@kernel.org>
CommitterDate: Thu, 07 Jul 2022 09:04:13 +01:00

genirq: Don't return error on missing optional irq_request_resources()

Function irq_chip::irq_request_resources() is reported as optional
in the declaration of struct irq_chip.
If the parent irq_chip does not implement it, we should ignore it
and return.

Don't return error if the functions is missing.

Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220512160544.13561-1-antonio.borneo@foss.st.com
---
 kernel/irq/chip.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 886789d..c190405 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1516,7 +1516,8 @@ int irq_chip_request_resources_parent(struct irq_data *data)
 	if (data->chip->irq_request_resources)
 		return data->chip->irq_request_resources(data);
 
-	return -ENOSYS;
+	/* no error on missing optional irq_chip::irq_request_resources */
+	return 0;
 }
 EXPORT_SYMBOL_GPL(irq_chip_request_resources_parent);