1 files changed, 201 insertions, 186 deletions

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 27ca1c866f29..b64c57b44c20 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -15,6 +15,7 @@
 #include <linux/maple_tree.h>
 #include <linux/irqdomain.h>
 #include <linux/sysfs.h>
+#include <linux/string_choices.h>
 
 #include "internals.h"
 
@@ -92,11 +93,23 @@ static void desc_smp_init(struct irq_desc *desc, int node,
 #endif
 }
 
+static void free_masks(struct irq_desc *desc)
+{
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+	free_cpumask_var(desc->pending_mask);
+#endif
+	free_cpumask_var(desc->irq_common_data.affinity);
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	free_cpumask_var(desc->irq_common_data.effective_affinity);
+#endif
+}
+
 #else
 static inline int
 alloc_masks(struct irq_desc *desc, int node) { return 0; }
 static inline void
 desc_smp_init(struct irq_desc *desc, int node, const struct cpumask *affinity) { }
+static inline void free_masks(struct irq_desc *desc) { }
 #endif
 
 static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
@@ -122,12 +135,34 @@ static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
 	desc->name = NULL;
 	desc->owner = owner;
 	for_each_possible_cpu(cpu)
-		*per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
+		*per_cpu_ptr(desc->kstat_irqs, cpu) = (struct irqstat) { };
 	desc_smp_init(desc, node, affinity);
 }
 
-int nr_irqs = NR_IRQS;
-EXPORT_SYMBOL_GPL(nr_irqs);
+static unsigned int nr_irqs = NR_IRQS;
+
+/**
+ * irq_get_nr_irqs() - Number of interrupts supported by the system.
+ */
+unsigned int irq_get_nr_irqs(void)
+{
+	return nr_irqs;
+}
+EXPORT_SYMBOL_GPL(irq_get_nr_irqs);
+
+/**
+ * irq_set_nr_irqs() - Set the number of interrupts supported by the system.
+ * @nr: New number of interrupts.
+ *
+ * Return: @nr.
+ */
+unsigned int irq_set_nr_irqs(unsigned int nr)
+{
+	nr_irqs = nr;
+
+	return nr;
+}
+EXPORT_SYMBOL_GPL(irq_set_nr_irqs);
 
 static DEFINE_MUTEX(sparse_irq_lock);
 static struct maple_tree sparse_irqs = MTREE_INIT_EXT(sparse_irqs,
@@ -148,7 +183,10 @@ static int irq_find_free_area(unsigned int from, unsigned int cnt)
 static unsigned int irq_find_at_or_after(unsigned int offset)
 {
 	unsigned long index = offset;
-	struct irq_desc *desc = mt_find(&sparse_irqs, &index, nr_irqs);
+	struct irq_desc *desc;
+
+	guard(rcu)();
+	desc = mt_find(&sparse_irqs, &index, nr_irqs);
 
 	return desc ? irq_desc_get_irq(desc) : nr_irqs;
 }
@@ -166,6 +204,39 @@ static void delete_irq_desc(unsigned int irq)
 }
 
 #ifdef CONFIG_SPARSE_IRQ
+static const struct kobj_type irq_kobj_type;
+#endif
+
+static int init_desc(struct irq_desc *desc, int irq, int node,
+		     unsigned int flags,
+		     const struct cpumask *affinity,
+		     struct module *owner)
+{
+	desc->kstat_irqs = alloc_percpu(struct irqstat);
+	if (!desc->kstat_irqs)
+		return -ENOMEM;
+
+	if (alloc_masks(desc, node)) {
+		free_percpu(desc->kstat_irqs);
+		return -ENOMEM;
+	}
+
+	raw_spin_lock_init(&desc->lock);
+	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+	mutex_init(&desc->request_mutex);
+	init_waitqueue_head(&desc->wait_for_threads);
+	desc_set_defaults(irq, desc, node, affinity, owner);
+	irqd_set(&desc->irq_data, flags);
+	irq_resend_init(desc);
+#ifdef CONFIG_SPARSE_IRQ
+	kobject_init(&desc->kobj, &irq_kobj_type);
+	init_rcu_head(&desc->rcu);
+#endif
+
+	return 0;
+}
+
+#ifdef CONFIG_SPARSE_IRQ
 
 static void irq_kobj_release(struct kobject *kobj);
 
@@ -175,8 +246,7 @@ static struct kobject *irq_kobj_base;
 #define IRQ_ATTR_RO(_name) \
 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 
-static ssize_t per_cpu_count_show(struct kobject *kobj,
-				  struct kobj_attribute *attr, char *buf)
+static ssize_t per_cpu_count_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
 	ssize_t ret = 0;
@@ -186,113 +256,83 @@ static ssize_t per_cpu_count_show(struct kobject *kobj,
 	for_each_possible_cpu(cpu) {
 		unsigned int c = irq_desc_kstat_cpu(desc, cpu);
 
-		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%u", p, c);
+		ret += sysfs_emit_at(buf, ret, "%s%u", p, c);
 		p = ",";
 	}
 
-	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
+	ret += sysfs_emit_at(buf, ret, "\n");
 	return ret;
 }
 IRQ_ATTR_RO(per_cpu_count);
 
-static ssize_t chip_name_show(struct kobject *kobj,
-			      struct kobj_attribute *attr, char *buf)
+static ssize_t chip_name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
-	ssize_t ret = 0;
 
-	raw_spin_lock_irq(&desc->lock);
-	if (desc->irq_data.chip && desc->irq_data.chip->name) {
-		ret = scnprintf(buf, PAGE_SIZE, "%s\n",
-				desc->irq_data.chip->name);
-	}
-	raw_spin_unlock_irq(&desc->lock);
-
-	return ret;
+	guard(raw_spinlock_irq)(&desc->lock);
+	if (desc->irq_data.chip && desc->irq_data.chip->name)
+		return sysfs_emit(buf, "%s\n", desc->irq_data.chip->name);
+	return 0;
 }
 IRQ_ATTR_RO(chip_name);
 
-static ssize_t hwirq_show(struct kobject *kobj,
-			  struct kobj_attribute *attr, char *buf)
+static ssize_t hwirq_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
-	ssize_t ret = 0;
 
-	raw_spin_lock_irq(&desc->lock);
+	guard(raw_spinlock_irq)(&desc->lock);
 	if (desc->irq_data.domain)
-		ret = sprintf(buf, "%lu\n", desc->irq_data.hwirq);
-	raw_spin_unlock_irq(&desc->lock);
-
-	return ret;
+		return sysfs_emit(buf, "%lu\n", desc->irq_data.hwirq);
+	return 0;
 }
 IRQ_ATTR_RO(hwirq);
 
-static ssize_t type_show(struct kobject *kobj,
-			 struct kobj_attribute *attr, char *buf)
+static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
-	ssize_t ret = 0;
 
-	raw_spin_lock_irq(&desc->lock);
-	ret = sprintf(buf, "%s\n",
-		      irqd_is_level_type(&desc->irq_data) ? "level" : "edge");
-	raw_spin_unlock_irq(&desc->lock);
-
-	return ret;
+	guard(raw_spinlock_irq)(&desc->lock);
+	return sysfs_emit(buf, "%s\n", irqd_is_level_type(&desc->irq_data) ? "level" : "edge");
 
 }
 IRQ_ATTR_RO(type);
 
-static ssize_t wakeup_show(struct kobject *kobj,
-			   struct kobj_attribute *attr, char *buf)
+static ssize_t wakeup_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
-	ssize_t ret = 0;
-
-	raw_spin_lock_irq(&desc->lock);
-	ret = sprintf(buf, "%s\n",
-		      irqd_is_wakeup_set(&desc->irq_data) ? "enabled" : "disabled");
-	raw_spin_unlock_irq(&desc->lock);
-
-	return ret;
 
+	guard(raw_spinlock_irq)(&desc->lock);
+	return sysfs_emit(buf, "%s\n", str_enabled_disabled(irqd_is_wakeup_set(&desc->irq_data)));
 }
 IRQ_ATTR_RO(wakeup);
 
-static ssize_t name_show(struct kobject *kobj,
-			 struct kobj_attribute *attr, char *buf)
+static ssize_t name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
-	ssize_t ret = 0;
 
-	raw_spin_lock_irq(&desc->lock);
+	guard(raw_spinlock_irq)(&desc->lock);
 	if (desc->name)
-		ret = scnprintf(buf, PAGE_SIZE, "%s\n", desc->name);
-	raw_spin_unlock_irq(&desc->lock);
-
-	return ret;
+		return sysfs_emit(buf, "%s\n", desc->name);
+	return 0;
 }
 IRQ_ATTR_RO(name);
 
-static ssize_t actions_show(struct kobject *kobj,
-			    struct kobj_attribute *attr, char *buf)
+static ssize_t actions_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
 	struct irqaction *action;
 	ssize_t ret = 0;
 	char *p = "";
 
-	raw_spin_lock_irq(&desc->lock);
-	for_each_action_of_desc(desc, action) {
-		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
-				 p, action->name);
-		p = ",";
+	scoped_guard(raw_spinlock_irq, &desc->lock) {
+		for_each_action_of_desc(desc, action) {
+			ret += sysfs_emit_at(buf, ret, "%s%s", p, action->name);
+			p = ",";
+		}
 	}
-	raw_spin_unlock_irq(&desc->lock);
 
 	if (ret)
-		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
-
+		ret += sysfs_emit_at(buf, ret, "\n");
 	return ret;
 }
 IRQ_ATTR_RO(actions);
@@ -348,19 +388,14 @@ static int __init irq_sysfs_init(void)
 	int irq;
 
 	/* Prevent concurrent irq alloc/free */
-	irq_lock_sparse();
-
+	guard(mutex)(&sparse_irq_lock);
 	irq_kobj_base = kobject_create_and_add("irq", kernel_kobj);
-	if (!irq_kobj_base) {
-		irq_unlock_sparse();
+	if (!irq_kobj_base)
 		return -ENOMEM;
-	}
 
 	/* Add the already allocated interrupts */
 	for_each_irq_desc(irq, desc)
 		irq_sysfs_add(irq, desc);
-	irq_unlock_sparse();
-
 	return 0;
 }
 postcore_initcall(irq_sysfs_init);
@@ -384,21 +419,6 @@ struct irq_desc *irq_to_desc(unsigned int irq)
 EXPORT_SYMBOL_GPL(irq_to_desc);
 #endif
 
-#ifdef CONFIG_SMP
-static void free_masks(struct irq_desc *desc)
-{
-#ifdef CONFIG_GENERIC_PENDING_IRQ
-	free_cpumask_var(desc->pending_mask);
-#endif
-	free_cpumask_var(desc->irq_common_data.affinity);
-#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
-	free_cpumask_var(desc->irq_common_data.effective_affinity);
-#endif
-}
-#else
-static inline void free_masks(struct irq_desc *desc) { }
-#endif
-
 void irq_lock_sparse(void)
 {
 	mutex_lock(&sparse_irq_lock);
@@ -414,36 +434,19 @@ static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags,
 				   struct module *owner)
 {
 	struct irq_desc *desc;
+	int ret;
 
 	desc = kzalloc_node(sizeof(*desc), GFP_KERNEL, node);
 	if (!desc)
 		return NULL;
-	/* allocate based on nr_cpu_ids */
-	desc->kstat_irqs = alloc_percpu(unsigned int);
-	if (!desc->kstat_irqs)
-		goto err_desc;
-
-	if (alloc_masks(desc, node))
-		goto err_kstat;
-
-	raw_spin_lock_init(&desc->lock);
-	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
-	mutex_init(&desc->request_mutex);
-	init_rcu_head(&desc->rcu);
-	init_waitqueue_head(&desc->wait_for_threads);
 
-	desc_set_defaults(irq, desc, node, affinity, owner);
-	irqd_set(&desc->irq_data, flags);
-	kobject_init(&desc->kobj, &irq_kobj_type);
-	irq_resend_init(desc);
+	ret = init_desc(desc, irq, node, flags, affinity, owner);
+	if (unlikely(ret)) {
+		kfree(desc);
+		return NULL;
+	}
 
 	return desc;
-
-err_kstat:
-	free_percpu(desc->kstat_irqs);
-err_desc:
-	kfree(desc);
-	return NULL;
 }
 
 static void irq_kobj_release(struct kobject *kobj)
@@ -514,6 +517,7 @@ static int alloc_descs(unsigned int start, unsigned int cnt, int node,
 				flags = IRQD_AFFINITY_MANAGED |
 					IRQD_MANAGED_SHUTDOWN;
 			}
+			flags |= IRQD_AFFINITY_SET;
 			mask = &affinity->mask;
 			node = cpu_to_node(cpumask_first(mask));
 			affinity++;
@@ -534,12 +538,12 @@ err:
 	return -ENOMEM;
 }
 
-static int irq_expand_nr_irqs(unsigned int nr)
+static bool irq_expand_nr_irqs(unsigned int nr)
 {
 	if (nr > MAX_SPARSE_IRQS)
-		return -ENOMEM;
+		return false;
 	nr_irqs = nr;
-	return 0;
+	return true;
 }
 
 int __init early_irq_init(void)
@@ -583,26 +587,29 @@ struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 int __init early_irq_init(void)
 {
 	int count, i, node = first_online_node;
-	struct irq_desc *desc;
+	int ret;
 
 	init_irq_default_affinity();
 
 	printk(KERN_INFO "NR_IRQS: %d\n", NR_IRQS);
 
-	desc = irq_desc;
 	count = ARRAY_SIZE(irq_desc);
 
 	for (i = 0; i < count; i++) {
-		desc[i].kstat_irqs = alloc_percpu(unsigned int);
-		alloc_masks(&desc[i], node);
-		raw_spin_lock_init(&desc[i].lock);
-		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
-		mutex_init(&desc[i].request_mutex);
-		init_waitqueue_head(&desc[i].wait_for_threads);
-		desc_set_defaults(i, &desc[i], node, NULL, NULL);
-		irq_resend_init(desc);
+		ret = init_desc(irq_desc + i, i, node, 0, NULL, NULL);
+		if (unlikely(ret))
+			goto __free_desc_res;
 	}
+
 	return arch_early_irq_init();
+
+__free_desc_res:
+	while (--i >= 0) {
+		free_masks(irq_desc + i);
+		free_percpu(irq_desc[i].kstat_irqs);
+	}
+
+	return ret;
 }
 
 struct irq_desc *irq_to_desc(unsigned int irq)
@@ -614,11 +621,9 @@ EXPORT_SYMBOL(irq_to_desc);
 static void free_desc(unsigned int irq)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
-	unsigned long flags;
 
-	raw_spin_lock_irqsave(&desc->lock, flags);
-	desc_set_defaults(irq, desc, irq_desc_get_node(desc), NULL, NULL);
-	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	scoped_guard(raw_spinlock_irqsave, &desc->lock)
+		desc_set_defaults(irq, desc, irq_desc_get_node(desc), NULL, NULL);
 	delete_irq_desc(irq);
 }
 
@@ -637,16 +642,15 @@ static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
 	return start;
 }
 
-static int irq_expand_nr_irqs(unsigned int nr)
+static inline bool irq_expand_nr_irqs(unsigned int nr)
 {
-	return -ENOMEM;
+	return false;
 }
 
 void irq_mark_irq(unsigned int irq)
 {
-	mutex_lock(&sparse_irq_lock);
+	guard(mutex)(&sparse_irq_lock);
 	irq_insert_desc(irq, irq_desc + irq);
-	mutex_unlock(&sparse_irq_lock);
 }
 
 #ifdef CONFIG_GENERIC_IRQ_LEGACY
@@ -666,7 +670,7 @@ int handle_irq_desc(struct irq_desc *desc)
 		return -EINVAL;
 
 	data = irq_desc_get_irq_data(desc);
-	if (WARN_ON_ONCE(!in_hardirq() && handle_enforce_irqctx(data)))
+	if (WARN_ON_ONCE(!in_hardirq() && irqd_is_handle_enforce_irqctx(data)))
 		return -EPERM;
 
 	generic_handle_irq_desc(desc);
@@ -785,11 +789,9 @@ void irq_free_descs(unsigned int from, unsigned int cnt)
 	if (from >= nr_irqs || (from + cnt) > nr_irqs)
 		return;
 
-	mutex_lock(&sparse_irq_lock);
+	guard(mutex)(&sparse_irq_lock);
 	for (i = 0; i < cnt; i++)
 		free_desc(from + i);
-
-	mutex_unlock(&sparse_irq_lock);
 }
 EXPORT_SYMBOL_GPL(irq_free_descs);
 
@@ -806,11 +808,10 @@ EXPORT_SYMBOL_GPL(irq_free_descs);
  *
  * Returns the first irq number or error code
  */
-int __ref
-__irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
-		  struct module *owner, const struct irq_affinity_desc *affinity)
+int __ref __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
+			    struct module *owner, const struct irq_affinity_desc *affinity)
 {
-	int start, ret;
+	int start;
 
 	if (!cnt)
 		return -EINVAL;
@@ -828,22 +829,17 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
 		from = arch_dynirq_lower_bound(from);
 	}
 
-	mutex_lock(&sparse_irq_lock);
+	guard(mutex)(&sparse_irq_lock);
 
 	start = irq_find_free_area(from, cnt);
-	ret = -EEXIST;
 	if (irq >=0 && start != irq)
-		goto unlock;
+		return -EEXIST;
 
 	if (start + cnt > nr_irqs) {
-		ret = irq_expand_nr_irqs(start + cnt);
-		if (ret)
-			goto unlock;
+		if (!irq_expand_nr_irqs(start + cnt))
+			return -ENOMEM;
 	}
-	ret = alloc_descs(start, cnt, node, affinity, owner);
-unlock:
-	mutex_unlock(&sparse_irq_lock);
-	return ret;
+	return alloc_descs(start, cnt, node, affinity, owner);
 }
 EXPORT_SYMBOL_GPL(__irq_alloc_descs);
 
@@ -858,27 +854,27 @@ unsigned int irq_get_next_irq(unsigned int offset)
 	return irq_find_at_or_after(offset);
 }
 
-struct irq_desc *
-__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
-		    unsigned int check)
+struct irq_desc *__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
+				     unsigned int check)
 {
-	struct irq_desc *desc = irq_to_desc(irq);
+	struct irq_desc *desc;
 
-	if (desc) {
-		if (check & _IRQ_DESC_CHECK) {
-			if ((check & _IRQ_DESC_PERCPU) &&
-			    !irq_settings_is_per_cpu_devid(desc))
-				return NULL;
-
-			if (!(check & _IRQ_DESC_PERCPU) &&
-			    irq_settings_is_per_cpu_devid(desc))
-				return NULL;
-		}
+	desc = irq_to_desc(irq);
+	if (!desc)
+		return NULL;
+
+	if (check & _IRQ_DESC_CHECK) {
+		if ((check & _IRQ_DESC_PERCPU) && !irq_settings_is_per_cpu_devid(desc))
+			return NULL;
 
-		if (bus)
-			chip_bus_lock(desc);
-		raw_spin_lock_irqsave(&desc->lock, *flags);
+		if (!(check & _IRQ_DESC_PERCPU) && irq_settings_is_per_cpu_devid(desc))
+			return NULL;
 	}
+
+	if (bus)
+		chip_bus_lock(desc);
+	raw_spin_lock_irqsave(&desc->lock, *flags);
+
 	return desc;
 }
 
@@ -895,10 +891,7 @@ int irq_set_percpu_devid_partition(unsigned int irq,
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 
-	if (!desc)
-		return -EINVAL;
-
-	if (desc->percpu_enabled)
+	if (!desc || desc->percpu_enabled)
 		return -EINVAL;
 
 	desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);
@@ -906,10 +899,7 @@ int irq_set_percpu_devid_partition(unsigned int irq,
 	if (!desc->percpu_enabled)
 		return -ENOMEM;
 
-	if (affinity)
-		desc->percpu_affinity = affinity;
-	else
-		desc->percpu_affinity = cpu_possible_mask;
+	desc->percpu_affinity = affinity ? : cpu_possible_mask;
 
 	irq_set_percpu_devid_flags(irq);
 	return 0;
@@ -952,33 +942,58 @@ unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 
-	return desc && desc->kstat_irqs ?
-			*per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
-}
-
-static bool irq_is_nmi(struct irq_desc *desc)
-{
-	return desc->istate & IRQS_NMI;
+	return desc && desc->kstat_irqs ? per_cpu(desc->kstat_irqs->cnt, cpu) : 0;
 }
 
-static unsigned int kstat_irqs(unsigned int irq)
+static unsigned int kstat_irqs_desc(struct irq_desc *desc, const struct cpumask *cpumask)
 {
-	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned int sum = 0;
 	int cpu;
 
-	if (!desc || !desc->kstat_irqs)
-		return 0;
 	if (!irq_settings_is_per_cpu_devid(desc) &&
 	    !irq_settings_is_per_cpu(desc) &&
 	    !irq_is_nmi(desc))
 		return data_race(desc->tot_count);
 
-	for_each_possible_cpu(cpu)
-		sum += data_race(*per_cpu_ptr(desc->kstat_irqs, cpu));
+	for_each_cpu(cpu, cpumask)
+		sum += data_race(per_cpu(desc->kstat_irqs->cnt, cpu));
 	return sum;
 }
 
+static unsigned int kstat_irqs(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc || !desc->kstat_irqs)
+		return 0;
+	return kstat_irqs_desc(desc, cpu_possible_mask);
+}
+
+#ifdef CONFIG_GENERIC_IRQ_STAT_SNAPSHOT
+
+void kstat_snapshot_irqs(void)
+{
+	struct irq_desc *desc;
+	unsigned int irq;
+
+	for_each_irq_desc(irq, desc) {
+		if (!desc->kstat_irqs)
+			continue;
+		this_cpu_write(desc->kstat_irqs->ref, this_cpu_read(desc->kstat_irqs->cnt));
+	}
+}
+
+unsigned int kstat_get_irq_since_snapshot(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc || !desc->kstat_irqs)
+		return 0;
+	return this_cpu_read(desc->kstat_irqs->cnt) - this_cpu_read(desc->kstat_irqs->ref);
+}
+
+#endif
+
 /**
  * kstat_irqs_usr - Get the statistics for an interrupt from thread context
  * @irq:	The interrupt number