| Message ID | 1606757759-6076-2-git-send-email-john.garry@huawei.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Support managed interrupts for platform devices | expand |
Hi Thomas, I'll go with something extra like: > >> Add a function to allow the affinity of an interrupt be switched to >> managed, such that interrupts allocated for platform devices may be >> managed. > > Could you please add a paragraph which explains the limitations of that > interface? This new interface has certain limitations, and attempts to use it in the following circumstances will fail: - For when the kernel is configured for generic IRQ reservation mode (in config GENERIC_IRQ_RESERVATION_MODE). The reason being that it could conflict with managed vs. non-managed interrupt accounting there. - The interrupt is already started, which should not be the case during init - The interrupt is already configured as managed, which means double init > >> +/** >> + * irq_update_affinity_desc - Update affinity management for an interrupt >> + * @irq: The interrupt number to update >> + * @affinity: Pointer to the affinity descriptor >> + * >> + * This interface can be used to configure the affinity management of >> + * interrupts which have been allocated already. > /* * There are certain limitations on when it may be used - attempts to use it for when the kernel is configured for generic IRQ reservation mode (in config GENERIC_IRQ_RESERVATION_MODE) will fail, as it may conflict with managed/non-managed interrupt accounting. In addition, attempts to use it on an interrupt which is already started or which has already been configured as managed will also fail, as these mean invalid init state or double init. ... Let me know if not good, if not I'll post again soon. Thanks, John
On Tue, Dec 01 2020 at 15:22, John Garry wrote: > /* > * There are certain limitations on when it may be used - attempts to > use it for when the kernel is configured for generic IRQ reservation > mode (in config GENERIC_IRQ_RESERVATION_MODE) will fail, as it may > conflict with managed/non-managed interrupt accounting. In addition, > attempts to use it on an interrupt which is already started or which has > already been configured as managed will also fail, as these mean invalid > init state or double init. > > ... > > Let me know if not good, if not I'll post again soon. LGTM
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index ee8299eb1f52..870b3251e174 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -352,6 +352,8 @@ extern int irq_can_set_affinity(unsigned int irq); extern int irq_select_affinity(unsigned int irq); extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m); +extern int irq_update_affinity_desc(unsigned int irq, + struct irq_affinity_desc *affinity); extern int irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify); @@ -387,6 +389,12 @@ static inline int irq_set_affinity_hint(unsigned int irq, return -EINVAL; } +static inline int irq_update_affinity_desc(unsigned int irq, + struct irq_affinity_desc *affinity) +{ + return -EINVAL; +} + static inline int irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify) { diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index c460e0496006..791691cb9005 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -371,6 +371,69 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask, return ret; } +/** + * irq_update_affinity_desc - Update affinity management for an interrupt + * @irq: The interrupt number to update + * @affinity: Pointer to the affinity descriptor + * + * This interface can be used to configure the affinity management of + * interrupts which have been allocated already. + */ +int irq_update_affinity_desc(unsigned int irq, + struct irq_affinity_desc *affinity) +{ + struct irq_desc *desc; + unsigned long flags; + bool activated; + int ret = 0; + + /* + * Supporting this with the reservation scheme used by x86 needs + * some more thought. Fail it for now. + */ + if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE)) + return -EOPNOTSUPP; + + desc = irq_get_desc_buslock(irq, &flags, 0); + if (!desc) + return -EINVAL; + + /* Requires the interrupt to be shut down */ + if (irqd_is_started(&desc->irq_data)) { + ret = -EBUSY; + goto out_unlock; + } + + /* Interrupts which are already managed cannot be modified */ + if (irqd_affinity_is_managed(&desc->irq_data)) { + ret = -EBUSY; + goto out_unlock; + } + + /* + * Deactivate the interrupt. That's required to undo + * anything an earlier activation has established. + */ + activated = irqd_is_activated(&desc->irq_data); + if (activated) + irq_domain_deactivate_irq(&desc->irq_data); + + if (affinity->is_managed) { + irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED); + irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN); + } + + cpumask_copy(desc->irq_common_data.affinity, &affinity->mask); + + /* Restore the activation state */ + if (activated) + irq_domain_activate_irq(&desc->irq_data, false); + +out_unlock: + irq_put_desc_busunlock(desc, flags); + return ret; +} + int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force) { struct irq_desc *desc = irq_to_desc(irq);
Add a function to allow the affinity of an interrupt be switched to managed, such that interrupts allocated for platform devices may be managed. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Garry <john.garry@huawei.com> --- include/linux/interrupt.h | 8 +++++ kernel/irq/manage.c | 63 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+) -- 2.26.2