arm64: fix a migrating irq bug when hotplug cpu

Yang Yingliang · ctmarinas · commit 217d453d473c · 2015-10-09T17:40:35.000+01:00
When cpu is disabled, all irqs will be migratged to another cpu.
In some cases, a new affinity is different, the old affinity need
to be updated and if irq_set_affinity's return value is IRQ_SET_MASK_OK_DONE,
the old affinity can not be updated. Fix it by using irq_do_set_affinity.

And migrating interrupts is a core code matter, so use the generic
function irq_migrate_all_off_this_cpu() to migrate interrupts in
kernel/irq/migration.c.

Cc: Jiang Liu &lt;jiang.liu@linux.intel.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Russell King - ARM Linux &lt;linux@arm.linux.org.uk&gt;
Cc: Hanjun Guo &lt;hanjun.guo@linaro.org&gt;
Acked-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Yang Yingliang &lt;yangyingliang@huawei.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
@@ -427,6 +427,7 @@ config NR_CPUS
 
 config HOTPLUG_CPU
 	bool "Support for hot-pluggable CPUs"
+	select GENERIC_IRQ_MIGRATION
 	help
 	  Say Y here to experiment with turning CPUs off and on.  CPUs
 	  can be controlled through /sys/devices/system/cpu.
diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
@@ -7,7 +7,6 @@
 
 struct pt_regs;
 
-extern void migrate_irqs(void);
 extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
 
 static inline void acpi_irq_init(void)
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
@@ -27,7 +27,6 @@
 #include <linux/init.h>
 #include <linux/irqchip.h>
 #include <linux/seq_file.h>
-#include <linux/ratelimit.h>
 
 unsigned long irq_err_count;
 
@@ -54,64 +53,3 @@ void __init init_IRQ(void)
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
 }
-
-#ifdef CONFIG_HOTPLUG_CPU
-static bool migrate_one_irq(struct irq_desc *desc)
-{
-	struct irq_data *d = irq_desc_get_irq_data(desc);
-	const struct cpumask *affinity = irq_data_get_affinity_mask(d);
-	struct irq_chip *c;
-	bool ret = false;
-
-	/*
-	 * If this is a per-CPU interrupt, or the affinity does not
-	 * include this CPU, then we have nothing to do.
-	 */
-	if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
-		return false;
-
-	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
-		affinity = cpu_online_mask;
-		ret = true;
-	}
-
-	c = irq_data_get_irq_chip(d);
-	if (!c->irq_set_affinity)
-		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
-	else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret)
-		cpumask_copy(irq_data_get_affinity_mask(d), affinity);
-
-	return ret;
-}
-
-/*
- * The current CPU has been marked offline.  Migrate IRQs off this CPU.
- * If the affinity settings do not allow other CPUs, force them onto any
- * available CPU.
- *
- * Note: we must iterate over all IRQs, whether they have an attached
- * action structure or not, as we need to get chained interrupts too.
- */
-void migrate_irqs(void)
-{
-	unsigned int i;
-	struct irq_desc *desc;
-	unsigned long flags;
-
-	local_irq_save(flags);
-
-	for_each_irq_desc(i, desc) {
-		bool affinity_broken;
-
-		raw_spin_lock(&desc->lock);
-		affinity_broken = migrate_one_irq(desc);
-		raw_spin_unlock(&desc->lock);
-
-		if (affinity_broken)
-			pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
-					    i, smp_processor_id());
-	}
-
-	local_irq_restore(flags);
-}
-#endif /* CONFIG_HOTPLUG_CPU */
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
@@ -231,7 +231,8 @@ int __cpu_disable(void)
 	/*
 	 * OK - migrate IRQs away from this CPU
 	 */
-	migrate_irqs();
+	irq_migrate_all_off_this_cpu();
+
 	return 0;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -231,7 +231,8 @@ int __cpu_disable(void)`
`231`	`231`	`/*`
`232`	`232`	`* OK - migrate IRQs away from this CPU`
`233`	`233`	`*/`
`234`		`- migrate_irqs();`
	`234`	`+ irq_migrate_all_off_this_cpu();`
	`235`	`+`
`235`	`236`	`return 0;`
`236`	`237`	`}`
`237`	`238`