2 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
3 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
5 * This file contains the interrupt descriptor management code
7 * Detailed information is available in Documentation/core-api/genericirq.rst
10 #include <linux/irq.h>
11 #include <linux/slab.h>
12 #include <linux/export.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel_stat.h>
15 #include <linux/radix-tree.h>
16 #include <linux/bitmap.h>
17 #include <linux/irqdomain.h>
18 #include <linux/sysfs.h>
20 #include "internals.h"
23 * lockdep: we want to handle all irq_desc locks as a single lock-class:
25 static struct lock_class_key irq_desc_lock_class;
27 #if defined(CONFIG_SMP)
28 static int __init irq_affinity_setup(char *str)
30 alloc_bootmem_cpumask_var(&irq_default_affinity);
31 cpulist_parse(str, irq_default_affinity);
33 * Set at least the boot cpu. We don't want to end up with
34 * bugreports caused by random comandline masks
36 cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
39 __setup("irqaffinity=", irq_affinity_setup);
41 static void __init init_irq_default_affinity(void)
43 if (!cpumask_available(irq_default_affinity))
44 zalloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
45 if (cpumask_empty(irq_default_affinity))
46 cpumask_setall(irq_default_affinity);
49 static void __init init_irq_default_affinity(void)
55 static int alloc_masks(struct irq_desc *desc, int node)
57 if (!zalloc_cpumask_var_node(&desc->irq_common_data.affinity,
61 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
62 if (!zalloc_cpumask_var_node(&desc->irq_common_data.effective_affinity,
64 free_cpumask_var(desc->irq_common_data.affinity);
69 #ifdef CONFIG_GENERIC_PENDING_IRQ
70 if (!zalloc_cpumask_var_node(&desc->pending_mask, GFP_KERNEL, node)) {
71 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
72 free_cpumask_var(desc->irq_common_data.effective_affinity);
74 free_cpumask_var(desc->irq_common_data.affinity);
81 static void desc_smp_init(struct irq_desc *desc, int node,
82 const struct cpumask *affinity)
85 affinity = irq_default_affinity;
86 cpumask_copy(desc->irq_common_data.affinity, affinity);
88 #ifdef CONFIG_GENERIC_PENDING_IRQ
89 cpumask_clear(desc->pending_mask);
92 desc->irq_common_data.node = node;
98 alloc_masks(struct irq_desc *desc, int node) { return 0; }
100 desc_smp_init(struct irq_desc *desc, int node, const struct cpumask *affinity) { }
103 static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
104 const struct cpumask *affinity, struct module *owner)
108 desc->irq_common_data.handler_data = NULL;
109 desc->irq_common_data.msi_desc = NULL;
111 desc->irq_data.common = &desc->irq_common_data;
112 desc->irq_data.irq = irq;
113 desc->irq_data.chip = &no_irq_chip;
114 desc->irq_data.chip_data = NULL;
115 irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
116 irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
117 irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
118 desc->handle_irq = handle_bad_irq;
121 desc->irqs_unhandled = 0;
125 for_each_possible_cpu(cpu)
126 *per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
127 desc_smp_init(desc, node, affinity);
130 int nr_irqs = NR_IRQS;
131 EXPORT_SYMBOL_GPL(nr_irqs);
133 static DEFINE_MUTEX(sparse_irq_lock);
134 static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
136 #ifdef CONFIG_SPARSE_IRQ
138 static void irq_kobj_release(struct kobject *kobj);
141 static struct kobject *irq_kobj_base;
143 #define IRQ_ATTR_RO(_name) \
144 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
146 static ssize_t per_cpu_count_show(struct kobject *kobj,
147 struct kobj_attribute *attr, char *buf)
149 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
150 int cpu, irq = desc->irq_data.irq;
154 for_each_possible_cpu(cpu) {
155 unsigned int c = kstat_irqs_cpu(irq, cpu);
157 ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%u", p, c);
161 ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
164 IRQ_ATTR_RO(per_cpu_count);
166 static ssize_t chip_name_show(struct kobject *kobj,
167 struct kobj_attribute *attr, char *buf)
169 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
172 raw_spin_lock_irq(&desc->lock);
173 if (desc->irq_data.chip && desc->irq_data.chip->name) {
174 ret = scnprintf(buf, PAGE_SIZE, "%s\n",
175 desc->irq_data.chip->name);
177 raw_spin_unlock_irq(&desc->lock);
181 IRQ_ATTR_RO(chip_name);
183 static ssize_t hwirq_show(struct kobject *kobj,
184 struct kobj_attribute *attr, char *buf)
186 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
189 raw_spin_lock_irq(&desc->lock);
190 if (desc->irq_data.domain)
191 ret = sprintf(buf, "%d\n", (int)desc->irq_data.hwirq);
192 raw_spin_unlock_irq(&desc->lock);
198 static ssize_t type_show(struct kobject *kobj,
199 struct kobj_attribute *attr, char *buf)
201 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
204 raw_spin_lock_irq(&desc->lock);
205 ret = sprintf(buf, "%s\n",
206 irqd_is_level_type(&desc->irq_data) ? "level" : "edge");
207 raw_spin_unlock_irq(&desc->lock);
214 static ssize_t name_show(struct kobject *kobj,
215 struct kobj_attribute *attr, char *buf)
217 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
220 raw_spin_lock_irq(&desc->lock);
222 ret = scnprintf(buf, PAGE_SIZE, "%s\n", desc->name);
223 raw_spin_unlock_irq(&desc->lock);
229 static ssize_t actions_show(struct kobject *kobj,
230 struct kobj_attribute *attr, char *buf)
232 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
233 struct irqaction *action;
237 raw_spin_lock_irq(&desc->lock);
238 for (action = desc->action; action != NULL; action = action->next) {
239 ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
243 raw_spin_unlock_irq(&desc->lock);
246 ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
250 IRQ_ATTR_RO(actions);
252 static struct attribute *irq_attrs[] = {
253 &per_cpu_count_attr.attr,
254 &chip_name_attr.attr,
262 static struct kobj_type irq_kobj_type = {
263 .release = irq_kobj_release,
264 .sysfs_ops = &kobj_sysfs_ops,
265 .default_attrs = irq_attrs,
268 static void irq_sysfs_add(int irq, struct irq_desc *desc)
272 * Continue even in case of failure as this is nothing
275 if (kobject_add(&desc->kobj, irq_kobj_base, "%d", irq))
276 pr_warn("Failed to add kobject for irq %d\n", irq);
280 static void irq_sysfs_del(struct irq_desc *desc)
283 * If irq_sysfs_init() has not yet been invoked (early boot), then
284 * irq_kobj_base is NULL and the descriptor was never added.
285 * kobject_del() complains about a object with no parent, so make
289 kobject_del(&desc->kobj);
292 static int __init irq_sysfs_init(void)
294 struct irq_desc *desc;
297 /* Prevent concurrent irq alloc/free */
300 irq_kobj_base = kobject_create_and_add("irq", kernel_kobj);
301 if (!irq_kobj_base) {
306 /* Add the already allocated interrupts */
307 for_each_irq_desc(irq, desc)
308 irq_sysfs_add(irq, desc);
313 postcore_initcall(irq_sysfs_init);
315 #else /* !CONFIG_SYSFS */
317 static struct kobj_type irq_kobj_type = {
318 .release = irq_kobj_release,
321 static void irq_sysfs_add(int irq, struct irq_desc *desc) {}
322 static void irq_sysfs_del(struct irq_desc *desc) {}
324 #endif /* CONFIG_SYSFS */
326 static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
328 static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
330 radix_tree_insert(&irq_desc_tree, irq, desc);
333 struct irq_desc *irq_to_desc(unsigned int irq)
335 return radix_tree_lookup(&irq_desc_tree, irq);
337 EXPORT_SYMBOL(irq_to_desc);
339 static void delete_irq_desc(unsigned int irq)
341 radix_tree_delete(&irq_desc_tree, irq);
345 static void free_masks(struct irq_desc *desc)
347 #ifdef CONFIG_GENERIC_PENDING_IRQ
348 free_cpumask_var(desc->pending_mask);
350 free_cpumask_var(desc->irq_common_data.affinity);
351 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
352 free_cpumask_var(desc->irq_common_data.effective_affinity);
356 static inline void free_masks(struct irq_desc *desc) { }
359 void irq_lock_sparse(void)
361 mutex_lock(&sparse_irq_lock);
364 void irq_unlock_sparse(void)
366 mutex_unlock(&sparse_irq_lock);
369 static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags,
370 const struct cpumask *affinity,
371 struct module *owner)
373 struct irq_desc *desc;
375 desc = kzalloc_node(sizeof(*desc), GFP_KERNEL, node);
378 /* allocate based on nr_cpu_ids */
379 desc->kstat_irqs = alloc_percpu(unsigned int);
380 if (!desc->kstat_irqs)
383 if (alloc_masks(desc, node))
386 raw_spin_lock_init(&desc->lock);
387 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
388 mutex_init(&desc->request_mutex);
389 init_rcu_head(&desc->rcu);
391 desc_set_defaults(irq, desc, node, affinity, owner);
392 irqd_set(&desc->irq_data, flags);
393 kobject_init(&desc->kobj, &irq_kobj_type);
398 free_percpu(desc->kstat_irqs);
404 static void irq_kobj_release(struct kobject *kobj)
406 struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
409 free_percpu(desc->kstat_irqs);
413 static void delayed_free_desc(struct rcu_head *rhp)
415 struct irq_desc *desc = container_of(rhp, struct irq_desc, rcu);
417 kobject_put(&desc->kobj);
420 static void free_desc(unsigned int irq)
422 struct irq_desc *desc = irq_to_desc(irq);
424 irq_remove_debugfs_entry(desc);
425 unregister_irq_proc(irq, desc);
428 * sparse_irq_lock protects also show_interrupts() and
429 * kstat_irq_usr(). Once we deleted the descriptor from the
430 * sparse tree we can free it. Access in proc will fail to
431 * lookup the descriptor.
433 * The sysfs entry must be serialized against a concurrent
434 * irq_sysfs_init() as well.
437 delete_irq_desc(irq);
440 * We free the descriptor, masks and stat fields via RCU. That
441 * allows demultiplex interrupts to do rcu based management of
442 * the child interrupts.
444 call_rcu(&desc->rcu, delayed_free_desc);
447 static int alloc_descs(unsigned int start, unsigned int cnt, int node,
448 const struct cpumask *affinity, struct module *owner)
450 const struct cpumask *mask = NULL;
451 struct irq_desc *desc;
455 /* Validate affinity mask(s) */
457 for (i = 0, mask = affinity; i < cnt; i++, mask++) {
458 if (cpumask_empty(mask))
463 flags = affinity ? IRQD_AFFINITY_MANAGED : 0;
466 for (i = 0; i < cnt; i++) {
468 node = cpu_to_node(cpumask_first(affinity));
472 desc = alloc_desc(start + i, node, flags, mask, owner);
475 irq_insert_desc(start + i, desc);
476 irq_sysfs_add(start + i, desc);
478 bitmap_set(allocated_irqs, start, cnt);
482 for (i--; i >= 0; i--)
483 free_desc(start + i);
487 static int irq_expand_nr_irqs(unsigned int nr)
489 if (nr > IRQ_BITMAP_BITS)
495 int __init early_irq_init(void)
497 int i, initcnt, node = first_online_node;
498 struct irq_desc *desc;
500 init_irq_default_affinity();
502 /* Let arch update nr_irqs and return the nr of preallocated irqs */
503 initcnt = arch_probe_nr_irqs();
504 printk(KERN_INFO "NR_IRQS: %d, nr_irqs: %d, preallocated irqs: %d\n",
505 NR_IRQS, nr_irqs, initcnt);
507 if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
508 nr_irqs = IRQ_BITMAP_BITS;
510 if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
511 initcnt = IRQ_BITMAP_BITS;
513 if (initcnt > nr_irqs)
516 for (i = 0; i < initcnt; i++) {
517 desc = alloc_desc(i, node, 0, NULL, NULL);
518 set_bit(i, allocated_irqs);
519 irq_insert_desc(i, desc);
521 return arch_early_irq_init();
524 #else /* !CONFIG_SPARSE_IRQ */
526 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
527 [0 ... NR_IRQS-1] = {
528 .handle_irq = handle_bad_irq,
530 .lock = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
534 int __init early_irq_init(void)
536 int count, i, node = first_online_node;
537 struct irq_desc *desc;
539 init_irq_default_affinity();
541 printk(KERN_INFO "NR_IRQS: %d\n", NR_IRQS);
544 count = ARRAY_SIZE(irq_desc);
546 for (i = 0; i < count; i++) {
547 desc[i].kstat_irqs = alloc_percpu(unsigned int);
548 alloc_masks(&desc[i], node);
549 raw_spin_lock_init(&desc[i].lock);
550 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
551 mutex_init(&desc[i].request_mutex);
552 desc_set_defaults(i, &desc[i], node, NULL, NULL);
554 return arch_early_irq_init();
557 struct irq_desc *irq_to_desc(unsigned int irq)
559 return (irq < NR_IRQS) ? irq_desc + irq : NULL;
561 EXPORT_SYMBOL(irq_to_desc);
563 static void free_desc(unsigned int irq)
565 struct irq_desc *desc = irq_to_desc(irq);
568 raw_spin_lock_irqsave(&desc->lock, flags);
569 desc_set_defaults(irq, desc, irq_desc_get_node(desc), NULL, NULL);
570 raw_spin_unlock_irqrestore(&desc->lock, flags);
573 static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
574 const struct cpumask *affinity,
575 struct module *owner)
579 for (i = 0; i < cnt; i++) {
580 struct irq_desc *desc = irq_to_desc(start + i);
584 bitmap_set(allocated_irqs, start, cnt);
588 static int irq_expand_nr_irqs(unsigned int nr)
593 void irq_mark_irq(unsigned int irq)
595 mutex_lock(&sparse_irq_lock);
596 bitmap_set(allocated_irqs, irq, 1);
597 mutex_unlock(&sparse_irq_lock);
600 #ifdef CONFIG_GENERIC_IRQ_LEGACY
601 void irq_init_desc(unsigned int irq)
607 #endif /* !CONFIG_SPARSE_IRQ */
610 * generic_handle_irq - Invoke the handler for a particular irq
611 * @irq: The irq number to handle
614 int generic_handle_irq(unsigned int irq)
616 struct irq_desc *desc = irq_to_desc(irq);
620 generic_handle_irq_desc(desc);
623 EXPORT_SYMBOL_GPL(generic_handle_irq);
625 #ifdef CONFIG_HANDLE_DOMAIN_IRQ
627 * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain
628 * @domain: The domain where to perform the lookup
629 * @hwirq: The HW irq number to convert to a logical one
630 * @lookup: Whether to perform the domain lookup or not
631 * @regs: Register file coming from the low-level handling code
633 * Returns: 0 on success, or -EINVAL if conversion has failed
635 int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
636 bool lookup, struct pt_regs *regs)
638 struct pt_regs *old_regs = set_irq_regs(regs);
639 unsigned int irq = hwirq;
644 #ifdef CONFIG_IRQ_DOMAIN
646 irq = irq_find_mapping(domain, hwirq);
650 * Some hardware gives randomly wrong interrupts. Rather
651 * than crashing, do something sensible.
653 if (unlikely(!irq || irq >= nr_irqs)) {
657 generic_handle_irq(irq);
661 set_irq_regs(old_regs);
666 /* Dynamic interrupt handling */
669 * irq_free_descs - free irq descriptors
670 * @from: Start of descriptor range
671 * @cnt: Number of consecutive irqs to free
673 void irq_free_descs(unsigned int from, unsigned int cnt)
677 if (from >= nr_irqs || (from + cnt) > nr_irqs)
680 mutex_lock(&sparse_irq_lock);
681 for (i = 0; i < cnt; i++)
684 bitmap_clear(allocated_irqs, from, cnt);
685 mutex_unlock(&sparse_irq_lock);
687 EXPORT_SYMBOL_GPL(irq_free_descs);
690 * irq_alloc_descs - allocate and initialize a range of irq descriptors
691 * @irq: Allocate for specific irq number if irq >= 0
692 * @from: Start the search from this irq number
693 * @cnt: Number of consecutive irqs to allocate.
694 * @node: Preferred node on which the irq descriptor should be allocated
695 * @owner: Owning module (can be NULL)
696 * @affinity: Optional pointer to an affinity mask array of size @cnt which
697 * hints where the irq descriptors should be allocated and which
698 * default affinities to use
700 * Returns the first irq number or error code
703 __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
704 struct module *owner, const struct cpumask *affinity)
717 * For interrupts which are freely allocated the
718 * architecture can force a lower bound to the @from
719 * argument. x86 uses this to exclude the GSI space.
721 from = arch_dynirq_lower_bound(from);
724 mutex_lock(&sparse_irq_lock);
726 start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
729 if (irq >=0 && start != irq)
732 if (start + cnt > nr_irqs) {
733 ret = irq_expand_nr_irqs(start + cnt);
737 ret = alloc_descs(start, cnt, node, affinity, owner);
739 mutex_unlock(&sparse_irq_lock);
742 EXPORT_SYMBOL_GPL(__irq_alloc_descs);
744 #ifdef CONFIG_GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
746 * irq_alloc_hwirqs - Allocate an irq descriptor and initialize the hardware
747 * @cnt: number of interrupts to allocate
748 * @node: node on which to allocate
750 * Returns an interrupt number > 0 or 0, if the allocation fails.
752 unsigned int irq_alloc_hwirqs(int cnt, int node)
754 int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL, NULL);
759 for (i = irq; cnt > 0; i++, cnt--) {
760 if (arch_setup_hwirq(i, node))
762 irq_clear_status_flags(i, _IRQ_NOREQUEST);
767 for (i--; i >= irq; i--) {
768 irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
769 arch_teardown_hwirq(i);
771 irq_free_descs(irq, cnt);
774 EXPORT_SYMBOL_GPL(irq_alloc_hwirqs);
777 * irq_free_hwirqs - Free irq descriptor and cleanup the hardware
778 * @from: Free from irq number
779 * @cnt: number of interrupts to free
782 void irq_free_hwirqs(unsigned int from, int cnt)
786 for (i = from, j = cnt; j > 0; i++, j--) {
787 irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
788 arch_teardown_hwirq(i);
790 irq_free_descs(from, cnt);
792 EXPORT_SYMBOL_GPL(irq_free_hwirqs);
796 * irq_get_next_irq - get next allocated irq number
797 * @offset: where to start the search
799 * Returns next irq number after offset or nr_irqs if none is found.
801 unsigned int irq_get_next_irq(unsigned int offset)
803 return find_next_bit(allocated_irqs, nr_irqs, offset);
807 __irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
810 struct irq_desc *desc = irq_to_desc(irq);
813 if (check & _IRQ_DESC_CHECK) {
814 if ((check & _IRQ_DESC_PERCPU) &&
815 !irq_settings_is_per_cpu_devid(desc))
818 if (!(check & _IRQ_DESC_PERCPU) &&
819 irq_settings_is_per_cpu_devid(desc))
825 raw_spin_lock_irqsave(&desc->lock, *flags);
830 void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
832 raw_spin_unlock_irqrestore(&desc->lock, flags);
834 chip_bus_sync_unlock(desc);
837 int irq_set_percpu_devid_partition(unsigned int irq,
838 const struct cpumask *affinity)
840 struct irq_desc *desc = irq_to_desc(irq);
845 if (desc->percpu_enabled)
848 desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);
850 if (!desc->percpu_enabled)
854 desc->percpu_affinity = affinity;
856 desc->percpu_affinity = cpu_possible_mask;
858 irq_set_percpu_devid_flags(irq);
862 int irq_set_percpu_devid(unsigned int irq)
864 return irq_set_percpu_devid_partition(irq, NULL);
867 int irq_get_percpu_devid_partition(unsigned int irq, struct cpumask *affinity)
869 struct irq_desc *desc = irq_to_desc(irq);
871 if (!desc || !desc->percpu_enabled)
875 cpumask_copy(affinity, desc->percpu_affinity);
880 void kstat_incr_irq_this_cpu(unsigned int irq)
882 kstat_incr_irqs_this_cpu(irq_to_desc(irq));
886 * kstat_irqs_cpu - Get the statistics for an interrupt on a cpu
887 * @irq: The interrupt number
888 * @cpu: The cpu number
890 * Returns the sum of interrupt counts on @cpu since boot for
891 * @irq. The caller must ensure that the interrupt is not removed
894 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
896 struct irq_desc *desc = irq_to_desc(irq);
898 return desc && desc->kstat_irqs ?
899 *per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
903 * kstat_irqs - Get the statistics for an interrupt
904 * @irq: The interrupt number
906 * Returns the sum of interrupt counts on all cpus since boot for
907 * @irq. The caller must ensure that the interrupt is not removed
910 unsigned int kstat_irqs(unsigned int irq)
912 struct irq_desc *desc = irq_to_desc(irq);
913 unsigned int sum = 0;
916 if (!desc || !desc->kstat_irqs)
918 if (!irq_settings_is_per_cpu_devid(desc) &&
919 !irq_settings_is_per_cpu(desc))
920 return desc->tot_count;
922 for_each_possible_cpu(cpu)
923 sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
928 * kstat_irqs_usr - Get the statistics for an interrupt
929 * @irq: The interrupt number
931 * Returns the sum of interrupt counts on all cpus since boot for
932 * @irq. Contrary to kstat_irqs() this can be called from any
933 * preemptible context. It's protected against concurrent removal of
934 * an interrupt descriptor when sparse irqs are enabled.
936 unsigned int kstat_irqs_usr(unsigned int irq)
941 sum = kstat_irqs(irq);