2020-11-25 11:19:23

by Laurent Vivier

[permalink] [raw]
Subject: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function

This function adds an affinity parameter to irq_create_mapping().
This parameter is needed to pass it to irq_domain_alloc_descs().

irq_create_mapping() is a wrapper around irq_create_mapping_affinity()
to pass NULL for the affinity parameter.

No functional change.

Signed-off-by: Laurent Vivier <[email protected]>
---
include/linux/irqdomain.h | 12 ++++++++++--
kernel/irq/irqdomain.c | 13 ++++++++-----
2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 71535e87109f..ea5a337e0f8b 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -384,11 +384,19 @@ extern void irq_domain_associate_many(struct irq_domain *domain,
extern void irq_domain_disassociate(struct irq_domain *domain,
unsigned int irq);

-extern unsigned int irq_create_mapping(struct irq_domain *host,
- irq_hw_number_t hwirq);
+extern unsigned int irq_create_mapping_affinity(struct irq_domain *host,
+ irq_hw_number_t hwirq,
+ const struct irq_affinity_desc *affinity);
extern unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec);
extern void irq_dispose_mapping(unsigned int virq);

+static inline unsigned int irq_create_mapping(struct irq_domain *host,
+ irq_hw_number_t hwirq)
+{
+ return irq_create_mapping_affinity(host, hwirq, NULL);
+}
+
+
/**
* irq_linear_revmap() - Find a linux irq from a hw irq number.
* @domain: domain owning this hardware interrupt
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index cf8b374b892d..e4ca69608f3b 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -624,17 +624,19 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain)
EXPORT_SYMBOL_GPL(irq_create_direct_mapping);

/**
- * irq_create_mapping() - Map a hardware interrupt into linux irq space
+ * irq_create_mapping_affinity() - Map a hardware interrupt into linux irq space
* @domain: domain owning this hardware interrupt or NULL for default domain
* @hwirq: hardware irq number in that domain space
+ * @affinity: irq affinity
*
* Only one mapping per hardware interrupt is permitted. Returns a linux
* irq number.
* If the sense/trigger is to be specified, set_irq_type() should be called
* on the number returned from that call.
*/
-unsigned int irq_create_mapping(struct irq_domain *domain,
- irq_hw_number_t hwirq)
+unsigned int irq_create_mapping_affinity(struct irq_domain *domain,
+ irq_hw_number_t hwirq,
+ const struct irq_affinity_desc *affinity)
{
struct device_node *of_node;
int virq;
@@ -660,7 +662,8 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
}

/* Allocate a virtual interrupt number */
- virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node), NULL);
+ virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node),
+ affinity);
if (virq <= 0) {
pr_debug("-> virq allocation failed\n");
return 0;
@@ -676,7 +679,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain,

return virq;
}
-EXPORT_SYMBOL_GPL(irq_create_mapping);
+EXPORT_SYMBOL_GPL(irq_create_mapping_affinity);

/**
* irq_create_strict_mappings() - Map a range of hw irqs to fixed linux irqs
--
2.28.0


2020-11-25 13:05:27

by Greg Kurz

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function

On Wed, 25 Nov 2020 12:16:56 +0100
Laurent Vivier <[email protected]> wrote:

> This function adds an affinity parameter to irq_create_mapping().
> This parameter is needed to pass it to irq_domain_alloc_descs().
>
> irq_create_mapping() is a wrapper around irq_create_mapping_affinity()
> to pass NULL for the affinity parameter.
>
> No functional change.
>
> Signed-off-by: Laurent Vivier <[email protected]>
> ---

Reviewed-by: Greg Kurz <[email protected]>

> include/linux/irqdomain.h | 12 ++++++++++--
> kernel/irq/irqdomain.c | 13 ++++++++-----
> 2 files changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
> index 71535e87109f..ea5a337e0f8b 100644
> --- a/include/linux/irqdomain.h
> +++ b/include/linux/irqdomain.h
> @@ -384,11 +384,19 @@ extern void irq_domain_associate_many(struct irq_domain *domain,
> extern void irq_domain_disassociate(struct irq_domain *domain,
> unsigned int irq);
>
> -extern unsigned int irq_create_mapping(struct irq_domain *host,
> - irq_hw_number_t hwirq);
> +extern unsigned int irq_create_mapping_affinity(struct irq_domain *host,
> + irq_hw_number_t hwirq,
> + const struct irq_affinity_desc *affinity);
> extern unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec);
> extern void irq_dispose_mapping(unsigned int virq);
>
> +static inline unsigned int irq_create_mapping(struct irq_domain *host,
> + irq_hw_number_t hwirq)
> +{
> + return irq_create_mapping_affinity(host, hwirq, NULL);
> +}
> +
> +
> /**
> * irq_linear_revmap() - Find a linux irq from a hw irq number.
> * @domain: domain owning this hardware interrupt
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index cf8b374b892d..e4ca69608f3b 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -624,17 +624,19 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain)
> EXPORT_SYMBOL_GPL(irq_create_direct_mapping);
>
> /**
> - * irq_create_mapping() - Map a hardware interrupt into linux irq space
> + * irq_create_mapping_affinity() - Map a hardware interrupt into linux irq space
> * @domain: domain owning this hardware interrupt or NULL for default domain
> * @hwirq: hardware irq number in that domain space
> + * @affinity: irq affinity
> *
> * Only one mapping per hardware interrupt is permitted. Returns a linux
> * irq number.
> * If the sense/trigger is to be specified, set_irq_type() should be called
> * on the number returned from that call.
> */
> -unsigned int irq_create_mapping(struct irq_domain *domain,
> - irq_hw_number_t hwirq)
> +unsigned int irq_create_mapping_affinity(struct irq_domain *domain,
> + irq_hw_number_t hwirq,
> + const struct irq_affinity_desc *affinity)
> {
> struct device_node *of_node;
> int virq;
> @@ -660,7 +662,8 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
> }
>
> /* Allocate a virtual interrupt number */
> - virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node), NULL);
> + virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node),
> + affinity);
> if (virq <= 0) {
> pr_debug("-> virq allocation failed\n");
> return 0;
> @@ -676,7 +679,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
>
> return virq;
> }
> -EXPORT_SYMBOL_GPL(irq_create_mapping);
> +EXPORT_SYMBOL_GPL(irq_create_mapping_affinity);
>
> /**
> * irq_create_strict_mappings() - Map a range of hw irqs to fixed linux irqs

2020-11-25 13:24:40

by Thomas Gleixner

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function

Laurent,

On Wed, Nov 25 2020 at 12:16, Laurent Vivier wrote:

The proper subsystem prefix is: 'genirq/irqdomain:' and the first letter
after the colon wants to be uppercase.

> This function adds an affinity parameter to irq_create_mapping().
> This parameter is needed to pass it to irq_domain_alloc_descs().

A changelog has to explain the WHY. 'The parameter is needed' is not
really useful information.

Thanks,

tglx

2020-11-25 14:14:36

by Laurent Vivier

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function

On 25/11/2020 14:20, Thomas Gleixner wrote:
> Laurent,
>
> On Wed, Nov 25 2020 at 12:16, Laurent Vivier wrote:
>
> The proper subsystem prefix is: 'genirq/irqdomain:' and the first letter
> after the colon wants to be uppercase.

Ok.

>> This function adds an affinity parameter to irq_create_mapping().
>> This parameter is needed to pass it to irq_domain_alloc_descs().
>
> A changelog has to explain the WHY. 'The parameter is needed' is not
> really useful information.
>

The reason of this change is explained in PATCH 2.

I have two patches, one to change the interface with no functional change (PATCH 1) and
one to fix the problem (PATCH 2). Moreover they don't cover the same subsystems.

I can either:
- merge the two patches
- or make a reference in the changelog of PATCH 1 to PATCH 2
(something like "(see folowing patch "powerpc/pseries: pass MSI affinity to
irq_create_mapping()")")
- or copy some information from PATCH 2
(something like "this parameter is needed by rtas_setup_msi_irqs() to pass the affinity
to irq_domain_alloc_descs() to fix multiqueue affinity")

What do you prefer?

Thanks,
Laurent

2020-11-25 15:06:35

by Laurent Vivier

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function

On 25/11/2020 15:54, Marc Zyngier wrote:
> On 2020-11-25 14:09, Laurent Vivier wrote:
>> On 25/11/2020 14:20, Thomas Gleixner wrote:
>>> Laurent,
>>>
>>> On Wed, Nov 25 2020 at 12:16, Laurent Vivier wrote:
>>>
>>> The proper subsystem prefix is: 'genirq/irqdomain:' and the first letter
>>> after the colon wants to be uppercase.
>>
>> Ok.
>>
>>>> This function adds an affinity parameter to irq_create_mapping().
>>>> This parameter is needed to pass it to irq_domain_alloc_descs().
>>>
>>> A changelog has to explain the WHY. 'The parameter is needed' is not
>>> really useful information.
>>>
>>
>> The reason of this change is explained in PATCH 2.
>>
>> I have two patches, one to change the interface with no functional
>> change (PATCH 1) and
>> one to fix the problem (PATCH 2). Moreover they don't cover the same subsystems.
>>
>> I can either:
>> - merge the two patches
>> - or make a reference in the changelog of PATCH 1 to PATCH 2
>>   (something like "(see folowing patch "powerpc/pseries: pass MSI affinity to
>>    irq_create_mapping()")")
>> - or copy some information from PATCH 2
>>   (something like "this parameter is needed by rtas_setup_msi_irqs()
>> to pass the affinity
>>    to irq_domain_alloc_descs() to fix multiqueue affinity")
>>
>> What do you prefer?
>
> How about something like this for the first patch:
>
> "There is currently no way to convey the affinity of an interrupt
>  via irq_create_mapping(), which creates issues for devices that
>  expect that affinity to be managed by the kernel.
>
>  In order to sort this out, rename irq_create_mapping() to
>  irq_create_mapping_affinity() with an additional affinity parameter
>  that can conveniently passed down to irq_domain_alloc_descs().
>
>  irq_create_mapping() is then re-implemented as a wrapper around
>  irq_create_mapping_affinity()."

It looks perfect. I update the changelog with that.

Thanks,
Laurent

2020-11-25 21:03:32

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function

On 2020-11-25 14:09, Laurent Vivier wrote:
> On 25/11/2020 14:20, Thomas Gleixner wrote:
>> Laurent,
>>
>> On Wed, Nov 25 2020 at 12:16, Laurent Vivier wrote:
>>
>> The proper subsystem prefix is: 'genirq/irqdomain:' and the first
>> letter
>> after the colon wants to be uppercase.
>
> Ok.
>
>>> This function adds an affinity parameter to irq_create_mapping().
>>> This parameter is needed to pass it to irq_domain_alloc_descs().
>>
>> A changelog has to explain the WHY. 'The parameter is needed' is not
>> really useful information.
>>
>
> The reason of this change is explained in PATCH 2.
>
> I have two patches, one to change the interface with no functional
> change (PATCH 1) and
> one to fix the problem (PATCH 2). Moreover they don't cover the same
> subsystems.
>
> I can either:
> - merge the two patches
> - or make a reference in the changelog of PATCH 1 to PATCH 2
> (something like "(see folowing patch "powerpc/pseries: pass MSI
> affinity to
> irq_create_mapping()")")
> - or copy some information from PATCH 2
> (something like "this parameter is needed by rtas_setup_msi_irqs()
> to pass the affinity
> to irq_domain_alloc_descs() to fix multiqueue affinity")
>
> What do you prefer?

How about something like this for the first patch:

"There is currently no way to convey the affinity of an interrupt
via irq_create_mapping(), which creates issues for devices that
expect that affinity to be managed by the kernel.

In order to sort this out, rename irq_create_mapping() to
irq_create_mapping_affinity() with an additional affinity parameter
that can conveniently passed down to irq_domain_alloc_descs().

irq_create_mapping() is then re-implemented as a wrapper around
irq_create_mapping_affinity()."

Thanks,

M.
--
Jazz is not dead. It just smells funny...