| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Wed, 21 Aug 2013 17:48:46 +0200 |
| Subject: genirq: Do not invoke the affinity callback via a workqueue on RT |
| |
| Joe Korty reported, that __irq_set_affinity_locked() schedules a |
| workqueue while holding a rawlock which results in a might_sleep() |
| warning. |
| This patch uses swork_queue() instead. |
| |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| include/linux/interrupt.h | 6 ++++++ |
| kernel/irq/manage.c | 43 ++++++++++++++++++++++++++++++++++++++++--- |
| 2 files changed, 46 insertions(+), 3 deletions(-) |
| |
| --- a/include/linux/interrupt.h |
| +++ b/include/linux/interrupt.h |
| @@ -14,6 +14,7 @@ |
| #include <linux/hrtimer.h> |
| #include <linux/kref.h> |
| #include <linux/workqueue.h> |
| +#include <linux/swork.h> |
| |
| #include <linux/atomic.h> |
| #include <asm/ptrace.h> |
| @@ -218,6 +219,7 @@ extern void resume_device_irqs(void); |
| * struct irq_affinity_notify - context for notification of IRQ affinity changes |
| * @irq: Interrupt to which notification applies |
| * @kref: Reference count, for internal use |
| + * @swork: Swork item, for internal use |
| * @work: Work item, for internal use |
| * @notify: Function to be called on change. This will be |
| * called in process context. |
| @@ -229,7 +231,11 @@ extern void resume_device_irqs(void); |
| struct irq_affinity_notify { |
| unsigned int irq; |
| struct kref kref; |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| + struct swork_event swork; |
| +#else |
| struct work_struct work; |
| +#endif |
| void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask); |
| void (*release)(struct kref *ref); |
| }; |
| --- a/kernel/irq/manage.c |
| +++ b/kernel/irq/manage.c |
| @@ -237,7 +237,12 @@ int irq_set_affinity_locked(struct irq_d |
| |
| if (desc->affinity_notify) { |
| kref_get(&desc->affinity_notify->kref); |
| + |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| + swork_queue(&desc->affinity_notify->swork); |
| +#else |
| schedule_work(&desc->affinity_notify->work); |
| +#endif |
| } |
| irqd_set(data, IRQD_AFFINITY_SET); |
| |
| @@ -275,10 +280,8 @@ int irq_set_affinity_hint(unsigned int i |
| } |
| EXPORT_SYMBOL_GPL(irq_set_affinity_hint); |
| |
| -static void irq_affinity_notify(struct work_struct *work) |
| +static void _irq_affinity_notify(struct irq_affinity_notify *notify) |
| { |
| - struct irq_affinity_notify *notify = |
| - container_of(work, struct irq_affinity_notify, work); |
| struct irq_desc *desc = irq_to_desc(notify->irq); |
| cpumask_var_t cpumask; |
| unsigned long flags; |
| @@ -300,6 +303,35 @@ static void irq_affinity_notify(struct w |
| kref_put(¬ify->kref, notify->release); |
| } |
| |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| +static void init_helper_thread(void) |
| +{ |
| + static int init_sworker_once; |
| + |
| + if (init_sworker_once) |
| + return; |
| + if (WARN_ON(swork_get())) |
| + return; |
| + init_sworker_once = 1; |
| +} |
| + |
| +static void irq_affinity_notify(struct swork_event *swork) |
| +{ |
| + struct irq_affinity_notify *notify = |
| + container_of(swork, struct irq_affinity_notify, swork); |
| + _irq_affinity_notify(notify); |
| +} |
| + |
| +#else |
| + |
| +static void irq_affinity_notify(struct work_struct *work) |
| +{ |
| + struct irq_affinity_notify *notify = |
| + container_of(work, struct irq_affinity_notify, work); |
| + _irq_affinity_notify(notify); |
| +} |
| +#endif |
| + |
| /** |
| * irq_set_affinity_notifier - control notification of IRQ affinity changes |
| * @irq: Interrupt for which to enable/disable notification |
| @@ -328,7 +360,12 @@ irq_set_affinity_notifier(unsigned int i |
| if (notify) { |
| notify->irq = irq; |
| kref_init(¬ify->kref); |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| + INIT_SWORK(¬ify->swork, irq_affinity_notify); |
| + init_helper_thread(); |
| +#else |
| INIT_WORK(¬ify->work, irq_affinity_notify); |
| +#endif |
| } |
| |
| raw_spin_lock_irqsave(&desc->lock, flags); |