Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux

[mirror_ubuntu-jammy-kernel.git] / kernel / irq / irqdesc.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
 *
 * This file contains the interrupt descriptor management code. Detailed
 * information is available in Documentation/core-api/genericirq.rst
 *
 */
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/radix-tree.h>
#include <linux/bitmap.h>
#include <linux/irqdomain.h>
#include <linux/sysfs.h>

#include "internals.h"

/*
 * lockdep: we want to handle all irq_desc locks as a single lock-class:
 */
static struct lock_class_key irq_desc_lock_class;

#if defined(CONFIG_SMP)
static int __init irq_affinity_setup(char *str)
{
        alloc_bootmem_cpumask_var(&irq_default_affinity);
        cpulist_parse(str, irq_default_affinity);
        /*
         * Set at least the boot cpu. We don't want to end up with
         * bugreports caused by random comandline masks
         */
        cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
        return 1;
}
__setup("irqaffinity=", irq_affinity_setup);

static void __init init_irq_default_affinity(void)
{
        if (!cpumask_available(irq_default_affinity))
                zalloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
        if (cpumask_empty(irq_default_affinity))
                cpumask_setall(irq_default_affinity);
}
#else
static void __init init_irq_default_affinity(void)
{
}
#endif

#ifdef CONFIG_SMP
static int alloc_masks(struct irq_desc *desc, int node)
{
        if (!zalloc_cpumask_var_node(&desc->irq_common_data.affinity,
                                     GFP_KERNEL, node))
                return -ENOMEM;

#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
        if (!zalloc_cpumask_var_node(&desc->irq_common_data.effective_affinity,
                                     GFP_KERNEL, node)) {
                free_cpumask_var(desc->irq_common_data.affinity);
                return -ENOMEM;
        }
#endif

#ifdef CONFIG_GENERIC_PENDING_IRQ
        if (!zalloc_cpumask_var_node(&desc->pending_mask, GFP_KERNEL, node)) {
#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
                free_cpumask_var(desc->irq_common_data.effective_affinity);
#endif
                free_cpumask_var(desc->irq_common_data.affinity);
                return -ENOMEM;
        }
#endif
        return 0;
}

static void desc_smp_init(struct irq_desc *desc, int node,
                          const struct cpumask *affinity)
{
        if (!affinity)
                affinity = irq_default_affinity;
        cpumask_copy(desc->irq_common_data.affinity, affinity);

#ifdef CONFIG_GENERIC_PENDING_IRQ
        cpumask_clear(desc->pending_mask);
#endif
#ifdef CONFIG_NUMA
        desc->irq_common_data.node = node;
#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) { }
#endif

static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
                              const struct cpumask *affinity, struct module *owner)
{
        int cpu;

        desc->irq_common_data.handler_data = NULL;
        desc->irq_common_data.msi_desc = NULL;

        desc->irq_data.common = &desc->irq_common_data;
        desc->irq_data.irq = irq;
        desc->irq_data.chip = &no_irq_chip;
        desc->irq_data.chip_data = NULL;
        irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
        irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
        irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
        desc->handle_irq = handle_bad_irq;
        desc->depth = 1;
        desc->irq_count = 0;
        desc->irqs_unhandled = 0;
        desc->tot_count = 0;
        desc->name = NULL;
        desc->owner = owner;
        for_each_possible_cpu(cpu)
                *per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
        desc_smp_init(desc, node, affinity);
}

int nr_irqs = NR_IRQS;
EXPORT_SYMBOL_GPL(nr_irqs);

static DEFINE_MUTEX(sparse_irq_lock);
static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);

#ifdef CONFIG_SPARSE_IRQ

static void irq_kobj_release(struct kobject *kobj);

#ifdef CONFIG_SYSFS
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)
{
        struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
        int cpu, irq = desc->irq_data.irq;
        ssize_t ret = 0;
        char *p = "";

        for_each_possible_cpu(cpu) {
                unsigned int c = kstat_irqs_cpu(irq, cpu);

                ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%u", p, c);
                p = ",";
        }

        ret += scnprintf(buf + ret, PAGE_SIZE - 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)
{
        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;
}
IRQ_ATTR_RO(chip_name);

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);
        if (desc->irq_data.domain)
                ret = sprintf(buf, "%d\n", (int)desc->irq_data.hwirq);
        raw_spin_unlock_irq(&desc->lock);

        return ret;
}
IRQ_ATTR_RO(hwirq);

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;

}
IRQ_ATTR_RO(type);

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;

}
IRQ_ATTR_RO(wakeup);

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);
        if (desc->name)
                ret = scnprintf(buf, PAGE_SIZE, "%s\n", desc->name);
        raw_spin_unlock_irq(&desc->lock);

        return ret;
}
IRQ_ATTR_RO(name);

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 (action = desc->action; action != NULL; action = action->next) {
                ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
                                 p, action->name);
                p = ",";
        }
        raw_spin_unlock_irq(&desc->lock);

        if (ret)
                ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");

        return ret;
}
IRQ_ATTR_RO(actions);

static struct attribute *irq_attrs[] = {
        &per_cpu_count_attr.attr,
        &chip_name_attr.attr,
        &hwirq_attr.attr,
        &type_attr.attr,
        &wakeup_attr.attr,
        &name_attr.attr,
        &actions_attr.attr,
        NULL
};
ATTRIBUTE_GROUPS(irq);

static struct kobj_type irq_kobj_type = {
        .release        = irq_kobj_release,
        .sysfs_ops      = &kobj_sysfs_ops,
        .default_groups = irq_groups,
};

static void irq_sysfs_add(int irq, struct irq_desc *desc)
{
        if (irq_kobj_base) {
                /*
                 * Continue even in case of failure as this is nothing
                 * crucial.
                 */
                if (kobject_add(&desc->kobj, irq_kobj_base, "%d", irq))
                        pr_warn("Failed to add kobject for irq %d\n", irq);
        }
}

static void irq_sysfs_del(struct irq_desc *desc)
{
        /*
         * If irq_sysfs_init() has not yet been invoked (early boot), then
         * irq_kobj_base is NULL and the descriptor was never added.
         * kobject_del() complains about a object with no parent, so make
         * it conditional.
         */
        if (irq_kobj_base)
                kobject_del(&desc->kobj);
}

static int __init irq_sysfs_init(void)
{
        struct irq_desc *desc;
        int irq;

        /* Prevent concurrent irq alloc/free */
        irq_lock_sparse();

        irq_kobj_base = kobject_create_and_add("irq", kernel_kobj);
        if (!irq_kobj_base) {
                irq_unlock_sparse();
                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);

#else /* !CONFIG_SYSFS */

static struct kobj_type irq_kobj_type = {
        .release        = irq_kobj_release,
};

static void irq_sysfs_add(int irq, struct irq_desc *desc) {}
static void irq_sysfs_del(struct irq_desc *desc) {}

#endif /* CONFIG_SYSFS */

static RADIX_TREE(irq_desc_tree, GFP_KERNEL);

static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
{
        radix_tree_insert(&irq_desc_tree, irq, desc);
}

struct irq_desc *irq_to_desc(unsigned int irq)
{
        return radix_tree_lookup(&irq_desc_tree, irq);
}
EXPORT_SYMBOL(irq_to_desc);

static void delete_irq_desc(unsigned int irq)
{
        radix_tree_delete(&irq_desc_tree, irq);
}

#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);
}

void irq_unlock_sparse(void)
{
        mutex_unlock(&sparse_irq_lock);
}

static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags,
                                   const struct cpumask *affinity,
                                   struct module *owner)
{
        struct irq_desc *desc;

        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);

        desc_set_defaults(irq, desc, node, affinity, owner);
        irqd_set(&desc->irq_data, flags);
        kobject_init(&desc->kobj, &irq_kobj_type);

        return desc;

err_kstat:
        free_percpu(desc->kstat_irqs);
err_desc:
        kfree(desc);
        return NULL;
}

static void irq_kobj_release(struct kobject *kobj)
{
        struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);

        free_masks(desc);
        free_percpu(desc->kstat_irqs);
        kfree(desc);
}

static void delayed_free_desc(struct rcu_head *rhp)
{
        struct irq_desc *desc = container_of(rhp, struct irq_desc, rcu);

        kobject_put(&desc->kobj);
}

static void free_desc(unsigned int irq)
{
        struct irq_desc *desc = irq_to_desc(irq);

        irq_remove_debugfs_entry(desc);
        unregister_irq_proc(irq, desc);

        /*
         * sparse_irq_lock protects also show_interrupts() and
         * kstat_irq_usr(). Once we deleted the descriptor from the
         * sparse tree we can free it. Access in proc will fail to
         * lookup the descriptor.
         *
         * The sysfs entry must be serialized against a concurrent
         * irq_sysfs_init() as well.
         */
        irq_sysfs_del(desc);
        delete_irq_desc(irq);

        /*
         * We free the descriptor, masks and stat fields via RCU. That
         * allows demultiplex interrupts to do rcu based management of
         * the child interrupts.
         * This also allows us to use rcu in kstat_irqs_usr().
         */
        call_rcu(&desc->rcu, delayed_free_desc);
}

static int alloc_descs(unsigned int start, unsigned int cnt, int node,
                       const struct irq_affinity_desc *affinity,
                       struct module *owner)
{
        struct irq_desc *desc;
        int i;

        /* Validate affinity mask(s) */
        if (affinity) {
                for (i = 0; i < cnt; i++) {
                        if (cpumask_empty(&affinity[i].mask))
                                return -EINVAL;
                }
        }

        for (i = 0; i < cnt; i++) {
                const struct cpumask *mask = NULL;
                unsigned int flags = 0;

                if (affinity) {
                        if (affinity->is_managed) {
                                flags = IRQD_AFFINITY_MANAGED |
                                        IRQD_MANAGED_SHUTDOWN;
                        }
                        mask = &affinity->mask;
                        node = cpu_to_node(cpumask_first(mask));
                        affinity++;
                }

                desc = alloc_desc(start + i, node, flags, mask, owner);
                if (!desc)
                        goto err;
                irq_insert_desc(start + i, desc);
                irq_sysfs_add(start + i, desc);
                irq_add_debugfs_entry(start + i, desc);
        }
        bitmap_set(allocated_irqs, start, cnt);
        return start;

err:
        for (i--; i >= 0; i--)
                free_desc(start + i);
        return -ENOMEM;
}

static int irq_expand_nr_irqs(unsigned int nr)
{
        if (nr > IRQ_BITMAP_BITS)
                return -ENOMEM;
        nr_irqs = nr;
        return 0;
}

int __init early_irq_init(void)
{
        int i, initcnt, node = first_online_node;
        struct irq_desc *desc;

        init_irq_default_affinity();

        /* Let arch update nr_irqs and return the nr of preallocated irqs */
        initcnt = arch_probe_nr_irqs();
        printk(KERN_INFO "NR_IRQS: %d, nr_irqs: %d, preallocated irqs: %d\n",
               NR_IRQS, nr_irqs, initcnt);

        if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
                nr_irqs = IRQ_BITMAP_BITS;

        if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
                initcnt = IRQ_BITMAP_BITS;

        if (initcnt > nr_irqs)
                nr_irqs = initcnt;

        for (i = 0; i < initcnt; i++) {
                desc = alloc_desc(i, node, 0, NULL, NULL);
                set_bit(i, allocated_irqs);
                irq_insert_desc(i, desc);
        }
        return arch_early_irq_init();
}

#else /* !CONFIG_SPARSE_IRQ */

struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
        [0 ... NR_IRQS-1] = {
                .handle_irq     = handle_bad_irq,
                .depth          = 1,
                .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
        }
};

int __init early_irq_init(void)
{
        int count, i, node = first_online_node;
        struct irq_desc *desc;

        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);
                desc_set_defaults(i, &desc[i], node, NULL, NULL);
        }
        return arch_early_irq_init();
}

struct irq_desc *irq_to_desc(unsigned int irq)
{
        return (irq < NR_IRQS) ? irq_desc + irq : NULL;
}
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);
}

static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
                              const struct irq_affinity_desc *affinity,
                              struct module *owner)
{
        u32 i;

        for (i = 0; i < cnt; i++) {
                struct irq_desc *desc = irq_to_desc(start + i);

                desc->owner = owner;
        }
        bitmap_set(allocated_irqs, start, cnt);
        return start;
}

static int irq_expand_nr_irqs(unsigned int nr)
{
        return -ENOMEM;
}

void irq_mark_irq(unsigned int irq)
{
        mutex_lock(&sparse_irq_lock);
        bitmap_set(allocated_irqs, irq, 1);
        mutex_unlock(&sparse_irq_lock);
}

#ifdef CONFIG_GENERIC_IRQ_LEGACY
void irq_init_desc(unsigned int irq)
{
        free_desc(irq);
}
#endif

#endif /* !CONFIG_SPARSE_IRQ */

/**
 * generic_handle_irq - Invoke the handler for a particular irq
 * @irq:        The irq number to handle
 *
 */
int generic_handle_irq(unsigned int irq)
{
        struct irq_desc *desc = irq_to_desc(irq);
        struct irq_data *data;

        if (!desc)
                return -EINVAL;

        data = irq_desc_get_irq_data(desc);
        if (WARN_ON_ONCE(!in_irq() && handle_enforce_irqctx(data)))
                return -EPERM;

        generic_handle_irq_desc(desc);
        return 0;
}
EXPORT_SYMBOL_GPL(generic_handle_irq);

#ifdef CONFIG_HANDLE_DOMAIN_IRQ
/**
 * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain
 * @domain:     The domain where to perform the lookup
 * @hwirq:      The HW irq number to convert to a logical one
 * @lookup:     Whether to perform the domain lookup or not
 * @regs:       Register file coming from the low-level handling code
 *
 * Returns:     0 on success, or -EINVAL if conversion has failed
 */
int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
                        bool lookup, struct pt_regs *regs)
{
        struct pt_regs *old_regs = set_irq_regs(regs);
        unsigned int irq = hwirq;
        int ret = 0;

        irq_enter();

#ifdef CONFIG_IRQ_DOMAIN
        if (lookup)
                irq = irq_find_mapping(domain, hwirq);
#endif

        /*
         * Some hardware gives randomly wrong interrupts.  Rather
         * than crashing, do something sensible.
         */
        if (unlikely(!irq || irq >= nr_irqs)) {
                ack_bad_irq(irq);
                ret = -EINVAL;
        } else {
                generic_handle_irq(irq);
        }

        irq_exit();
        set_irq_regs(old_regs);
        return ret;
}

#ifdef CONFIG_IRQ_DOMAIN
/**
 * handle_domain_nmi - Invoke the handler for a HW irq belonging to a domain
 * @domain:     The domain where to perform the lookup
 * @hwirq:      The HW irq number to convert to a logical one
 * @regs:       Register file coming from the low-level handling code
 *
 *              This function must be called from an NMI context.
 *
 * Returns:     0 on success, or -EINVAL if conversion has failed
 */
int handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq,
                      struct pt_regs *regs)
{
        struct pt_regs *old_regs = set_irq_regs(regs);
        unsigned int irq;
        int ret = 0;

        /*
         * NMI context needs to be setup earlier in order to deal with tracing.
         */
        WARN_ON(!in_nmi());

        irq = irq_find_mapping(domain, hwirq);

        /*
         * ack_bad_irq is not NMI-safe, just report
         * an invalid interrupt.
         */
        if (likely(irq))
                generic_handle_irq(irq);
        else
                ret = -EINVAL;

        set_irq_regs(old_regs);
        return ret;
}
#endif
#endif

/* Dynamic interrupt handling */

/**
 * irq_free_descs - free irq descriptors
 * @from:       Start of descriptor range
 * @cnt:        Number of consecutive irqs to free
 */
void irq_free_descs(unsigned int from, unsigned int cnt)
{
        int i;

        if (from >= nr_irqs || (from + cnt) > nr_irqs)
                return;

        mutex_lock(&sparse_irq_lock);
        for (i = 0; i < cnt; i++)
                free_desc(from + i);

        bitmap_clear(allocated_irqs, from, cnt);
        mutex_unlock(&sparse_irq_lock);
}
EXPORT_SYMBOL_GPL(irq_free_descs);

/**
 * __irq_alloc_descs - allocate and initialize a range of irq descriptors
 * @irq:        Allocate for specific irq number if irq >= 0
 * @from:       Start the search from this irq number
 * @cnt:        Number of consecutive irqs to allocate.
 * @node:       Preferred node on which the irq descriptor should be allocated
 * @owner:      Owning module (can be NULL)
 * @affinity:   Optional pointer to an affinity mask array of size @cnt which
 *              hints where the irq descriptors should be allocated and which
 *              default affinities to use
 *
 * 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 start, ret;

        if (!cnt)
                return -EINVAL;

        if (irq >= 0) {
                if (from > irq)
                        return -EINVAL;
                from = irq;
        } else {
                /*
                 * For interrupts which are freely allocated the
                 * architecture can force a lower bound to the @from
                 * argument. x86 uses this to exclude the GSI space.
                 */
                from = arch_dynirq_lower_bound(from);
        }

        mutex_lock(&sparse_irq_lock);

        start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
                                           from, cnt, 0);
        ret = -EEXIST;
        if (irq >=0 && start != irq)
                goto unlock;

        if (start + cnt > nr_irqs) {
                ret = irq_expand_nr_irqs(start + cnt);
                if (ret)
                        goto unlock;
        }
        ret = alloc_descs(start, cnt, node, affinity, owner);
unlock:
        mutex_unlock(&sparse_irq_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(__irq_alloc_descs);

/**
 * irq_get_next_irq - get next allocated irq number
 * @offset:     where to start the search
 *
 * Returns next irq number after offset or nr_irqs if none is found.
 */
unsigned int irq_get_next_irq(unsigned int offset)
{
        return find_next_bit(allocated_irqs, nr_irqs, offset);
}

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);

        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;
                }

                if (bus)
                        chip_bus_lock(desc);
                raw_spin_lock_irqsave(&desc->lock, *flags);
        }
        return desc;
}

void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
        __releases(&desc->lock)
{
        raw_spin_unlock_irqrestore(&desc->lock, flags);
        if (bus)
                chip_bus_sync_unlock(desc);
}

int irq_set_percpu_devid_partition(unsigned int irq,
                                   const struct cpumask *affinity)
{
        struct irq_desc *desc = irq_to_desc(irq);

        if (!desc)
                return -EINVAL;

        if (desc->percpu_enabled)
                return -EINVAL;

        desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);

        if (!desc->percpu_enabled)
                return -ENOMEM;

        if (affinity)
                desc->percpu_affinity = affinity;
        else
                desc->percpu_affinity = cpu_possible_mask;

        irq_set_percpu_devid_flags(irq);
        return 0;
}

int irq_set_percpu_devid(unsigned int irq)
{
        return irq_set_percpu_devid_partition(irq, NULL);
}

int irq_get_percpu_devid_partition(unsigned int irq, struct cpumask *affinity)
{
        struct irq_desc *desc = irq_to_desc(irq);

        if (!desc || !desc->percpu_enabled)
                return -EINVAL;

        if (affinity)
                cpumask_copy(affinity, desc->percpu_affinity);

        return 0;
}
EXPORT_SYMBOL_GPL(irq_get_percpu_devid_partition);

void kstat_incr_irq_this_cpu(unsigned int irq)
{
        kstat_incr_irqs_this_cpu(irq_to_desc(irq));
}

/**
 * kstat_irqs_cpu - Get the statistics for an interrupt on a cpu
 * @irq:        The interrupt number
 * @cpu:        The cpu number
 *
 * Returns the sum of interrupt counts on @cpu since boot for
 * @irq. The caller must ensure that the interrupt is not removed
 * concurrently.
 */
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;
}

/**
 * kstat_irqs - Get the statistics for an interrupt
 * @irq:        The interrupt number
 *
 * Returns the sum of interrupt counts on all cpus since boot for
 * @irq. The caller must ensure that the interrupt is not removed
 * concurrently.
 */
unsigned int kstat_irqs(unsigned int irq)
{
        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 desc->tot_count;

        for_each_possible_cpu(cpu)
                sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
        return sum;
}

/**
 * kstat_irqs_usr - Get the statistics for an interrupt
 * @irq:        The interrupt number
 *
 * Returns the sum of interrupt counts on all cpus since boot for @irq.
 * Contrary to kstat_irqs() this can be called from any context.
 * It uses rcu since a concurrent removal of an interrupt descriptor is
 * observing an rcu grace period before delayed_free_desc()/irq_kobj_release().
 */
unsigned int kstat_irqs_usr(unsigned int irq)
{
        unsigned int sum;

        rcu_read_lock();
        sum = kstat_irqs(irq);
        rcu_read_unlock();
        return sum;
}