kernel/irq/irqdesc.c - maze/linux - Git at Google

 /*
  * 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/DocBook/genericirq
  *
  */
 #include <linux/irq.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
 #include <linux/radix-tree.h>
 #include <linux/bitmap.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) && defined(CONFIG_GENERIC_HARDIRQS)
 static void __init init_irq_default_affinity(void)
 {
 	alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
 	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, gfp_t gfp, int node)
 {
 	if (!zalloc_cpumask_var_node(&desc->irq_data.affinity, gfp, node))
 		return -ENOMEM;

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

 static void desc_smp_init(struct irq_desc *desc, int node)
 {
 	desc->irq_data.node = node;
 	cpumask_copy(desc->irq_data.affinity, irq_default_affinity);
 #ifdef CONFIG_GENERIC_PENDING_IRQ
 	cpumask_clear(desc->pending_mask);
 #endif
 }

 static inline int desc_node(struct irq_desc *desc)
 {
 	return desc->irq_data.node;
 }

 #else
 static inline int
 alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; }
 static inline void desc_smp_init(struct irq_desc *desc, int node) { }
 static inline int desc_node(struct irq_desc *desc) { return 0; }
 #endif

 static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node)
 {
 	int cpu;

 	desc->irq_data.irq = irq;
 	desc->irq_data.chip = &no_irq_chip;
 	desc->irq_data.chip_data = NULL;
 	desc->irq_data.handler_data = NULL;
 	desc->irq_data.msi_desc = NULL;
 	desc->status = IRQ_DEFAULT_INIT_FLAGS;
 	desc->handle_irq = handle_bad_irq;
 	desc->depth = 1;
 	desc->irq_count = 0;
 	desc->irqs_unhandled = 0;
 	desc->name = NULL;
 	for_each_possible_cpu(cpu)
 		*per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
 	desc_smp_init(desc, node);
 }

 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 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);
 }

 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_data.affinity);
 }
 #else
 static inline void free_masks(struct irq_desc *desc) { }
 #endif

 static struct irq_desc *alloc_desc(int irq, int node)
 {
 	struct irq_desc *desc;
 	gfp_t gfp = GFP_KERNEL;

 	desc = kzalloc_node(sizeof(*desc), gfp, 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, gfp, node))
 		goto err_kstat;

 	raw_spin_lock_init(&desc->lock);
 	lockdep_set_class(&desc->lock, &irq_desc_lock_class);

 	desc_set_defaults(irq, desc, node);

 	return desc;

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

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

 	unregister_irq_proc(irq, desc);

 	mutex_lock(&sparse_irq_lock);
 	delete_irq_desc(irq);
 	mutex_unlock(&sparse_irq_lock);

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

 static int alloc_descs(unsigned int start, unsigned int cnt, int node)
 {
 	struct irq_desc *desc;
 	int i;

 	for (i = 0; i < cnt; i++) {
 		desc = alloc_desc(start + i, node);
 		if (!desc)
 			goto err;
 		mutex_lock(&sparse_irq_lock);
 		irq_insert_desc(start + i, desc);
 		mutex_unlock(&sparse_irq_lock);
 	}
 	return start;

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

 	mutex_lock(&sparse_irq_lock);
 	bitmap_clear(allocated_irqs, start, cnt);
 	mutex_unlock(&sparse_irq_lock);
 	return -ENOMEM;
 }

 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 {
 	int res = irq_alloc_descs(irq, irq, 1, node);

 	if (res == -EEXIST || res == irq)
 		return irq_to_desc(irq);
 	return NULL;
 }

 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 %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);
 		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] = {
 		.status		= IRQ_DEFAULT_INIT_FLAGS,
 		.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].irq_data.irq = i;
 		desc[i].irq_data.chip = &no_irq_chip;
 		/* TODO : do this allocation on-demand ... */
 		desc[i].kstat_irqs = alloc_percpu(unsigned int);
 		alloc_masks(desc + i, GFP_KERNEL, node);
 		desc_smp_init(desc + i, node);
 		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 	}
 	return arch_early_irq_init();
 }

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

 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 {
 	return irq_to_desc(irq);
 }

 static void free_desc(unsigned int irq)
 {
 	dynamic_irq_cleanup(irq);
 }

 static inline int alloc_descs(unsigned int start, unsigned int cnt, int node)
 {
 #if defined(CONFIG_KSTAT_IRQS_ONDEMAND)
 	struct irq_desc *desc;
 	unsigned int i;

 	for (i = 0; i < cnt; i++) {
 		desc = irq_to_desc(start + i);
 		if (desc && !desc->kstat_irqs) {
 			unsigned int __percpu *stats = alloc_percpu(unsigned int);

 			if (!stats)
 				return -1;
 			if (cmpxchg(&desc->kstat_irqs, NULL, stats) != NULL)
 				free_percpu(stats);
 		}
 	}
 #endif
 	return start;
 }
 #endif /* !CONFIG_SPARSE_IRQ */

 /* 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;

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

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

 /**
  * 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
  *
  * Returns the first irq number or error code
  */
 int __ref
 irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
 {
 	int start, ret;

 	if (!cnt)
 		return -EINVAL;

 	mutex_lock(&sparse_irq_lock);

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

 	ret = -ENOMEM;
 	if (start >= nr_irqs)
 		goto err;

 	bitmap_set(allocated_irqs, start, cnt);
 	mutex_unlock(&sparse_irq_lock);
 	return alloc_descs(start, cnt, node);

 err:
 	mutex_unlock(&sparse_irq_lock);
 	return ret;
 }

 /**
  * irq_reserve_irqs - mark irqs allocated
  * @from:	mark from irq number
  * @cnt:	number of irqs to mark
  *
  * Returns 0 on success or an appropriate error code
  */
 int irq_reserve_irqs(unsigned int from, unsigned int cnt)
 {
 	unsigned int start;
 	int ret = 0;

 	if (!cnt || (from + cnt) > nr_irqs)
 		return -EINVAL;

 	mutex_lock(&sparse_irq_lock);
 	start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
 	if (start == from)
 		bitmap_set(allocated_irqs, start, cnt);
 	else
 		ret = -EEXIST;
 	mutex_unlock(&sparse_irq_lock);
 	return ret;
 }

 /**
  * 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);
 }

 /**
  * dynamic_irq_cleanup - cleanup a dynamically allocated irq
  * @irq:	irq number to initialize
  */
 void dynamic_irq_cleanup(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, desc_node(desc));
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 }

 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;
 }

 #ifdef CONFIG_GENERIC_HARDIRQS
 unsigned int kstat_irqs(unsigned int irq)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 	int cpu;
 	int sum = 0;

 	if (!desc || !desc->kstat_irqs)
 		return 0;
 	for_each_possible_cpu(cpu)
 		sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
 	return sum;
 }
 #endif /* CONFIG_GENERIC_HARDIRQS */
	/*
	* 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/DocBook/genericirq
	*
	*/
	#include <linux/irq.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/kernel_stat.h>
	#include <linux/radix-tree.h>
	#include <linux/bitmap.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) && defined(CONFIG_GENERIC_HARDIRQS)
	static void __init init_irq_default_affinity(void)
	{
	alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
	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, gfp_t gfp, int node)
	{
	if (!zalloc_cpumask_var_node(&desc->irq_data.affinity, gfp, node))
	return -ENOMEM;

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

	static void desc_smp_init(struct irq_desc *desc, int node)
	{
	desc->irq_data.node = node;
	cpumask_copy(desc->irq_data.affinity, irq_default_affinity);
	#ifdef CONFIG_GENERIC_PENDING_IRQ
	cpumask_clear(desc->pending_mask);
	#endif
	}

	static inline int desc_node(struct irq_desc *desc)
	{
	return desc->irq_data.node;
	}

	#else
	static inline int
	alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; }
	static inline void desc_smp_init(struct irq_desc *desc, int node) { }
	static inline int desc_node(struct irq_desc *desc) { return 0; }
	#endif

	static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node)
	{
	int cpu;

	desc->irq_data.irq = irq;
	desc->irq_data.chip = &no_irq_chip;
	desc->irq_data.chip_data = NULL;
	desc->irq_data.handler_data = NULL;
	desc->irq_data.msi_desc = NULL;
	desc->status = IRQ_DEFAULT_INIT_FLAGS;
	desc->handle_irq = handle_bad_irq;
	desc->depth = 1;
	desc->irq_count = 0;
	desc->irqs_unhandled = 0;
	desc->name = NULL;
	for_each_possible_cpu(cpu)
	*per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
	desc_smp_init(desc, node);
	}

	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 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);
	}

	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_data.affinity);
	}
	#else
	static inline void free_masks(struct irq_desc *desc) { }
	#endif

	static struct irq_desc *alloc_desc(int irq, int node)
	{
	struct irq_desc *desc;
	gfp_t gfp = GFP_KERNEL;

	desc = kzalloc_node(sizeof(*desc), gfp, 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, gfp, node))
	goto err_kstat;

	raw_spin_lock_init(&desc->lock);
	lockdep_set_class(&desc->lock, &irq_desc_lock_class);

	desc_set_defaults(irq, desc, node);

	return desc;

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

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

	unregister_irq_proc(irq, desc);

	mutex_lock(&sparse_irq_lock);
	delete_irq_desc(irq);
	mutex_unlock(&sparse_irq_lock);

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

	static int alloc_descs(unsigned int start, unsigned int cnt, int node)
	{
	struct irq_desc *desc;
	int i;

	for (i = 0; i < cnt; i++) {
	desc = alloc_desc(start + i, node);
	if (!desc)
	goto err;
	mutex_lock(&sparse_irq_lock);
	irq_insert_desc(start + i, desc);
	mutex_unlock(&sparse_irq_lock);
	}
	return start;

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

	mutex_lock(&sparse_irq_lock);
	bitmap_clear(allocated_irqs, start, cnt);
	mutex_unlock(&sparse_irq_lock);
	return -ENOMEM;
	}

	struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
	{
	int res = irq_alloc_descs(irq, irq, 1, node);

	if (res == -EEXIST \|\| res == irq)
	return irq_to_desc(irq);
	return NULL;
	}

	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 %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);
	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] = {
	.status = IRQ_DEFAULT_INIT_FLAGS,
	.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].irq_data.irq = i;
	desc[i].irq_data.chip = &no_irq_chip;
	/* TODO : do this allocation on-demand ... */
	desc[i].kstat_irqs = alloc_percpu(unsigned int);
	alloc_masks(desc + i, GFP_KERNEL, node);
	desc_smp_init(desc + i, node);
	lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
	}
	return arch_early_irq_init();
	}

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

	struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
	{
	return irq_to_desc(irq);
	}

	static void free_desc(unsigned int irq)
	{
	dynamic_irq_cleanup(irq);
	}

	static inline int alloc_descs(unsigned int start, unsigned int cnt, int node)
	{
	#if defined(CONFIG_KSTAT_IRQS_ONDEMAND)
	struct irq_desc *desc;
	unsigned int i;

	for (i = 0; i < cnt; i++) {
	desc = irq_to_desc(start + i);
	if (desc && !desc->kstat_irqs) {
	unsigned int __percpu *stats = alloc_percpu(unsigned int);

	if (!stats)
	return -1;
	if (cmpxchg(&desc->kstat_irqs, NULL, stats) != NULL)
	free_percpu(stats);
	}
	}
	#endif
	return start;
	}
	#endif /* !CONFIG_SPARSE_IRQ */

	/* 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;

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

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

	/**
	* 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
	*
	* Returns the first irq number or error code
	*/
	int __ref
	irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
	{
	int start, ret;

	if (!cnt)
	return -EINVAL;

	mutex_lock(&sparse_irq_lock);

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

	ret = -ENOMEM;
	if (start >= nr_irqs)
	goto err;

	bitmap_set(allocated_irqs, start, cnt);
	mutex_unlock(&sparse_irq_lock);
	return alloc_descs(start, cnt, node);

	err:
	mutex_unlock(&sparse_irq_lock);
	return ret;
	}

	/**
	* irq_reserve_irqs - mark irqs allocated
	* @from: mark from irq number
	* @cnt: number of irqs to mark
	*
	* Returns 0 on success or an appropriate error code
	*/
	int irq_reserve_irqs(unsigned int from, unsigned int cnt)
	{
	unsigned int start;
	int ret = 0;

	if (!cnt \|\| (from + cnt) > nr_irqs)
	return -EINVAL;

	mutex_lock(&sparse_irq_lock);
	start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
	if (start == from)
	bitmap_set(allocated_irqs, start, cnt);
	else
	ret = -EEXIST;
	mutex_unlock(&sparse_irq_lock);
	return ret;
	}

	/**
	* 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);
	}

	/**
	* dynamic_irq_cleanup - cleanup a dynamically allocated irq
	* @irq: irq number to initialize
	*/
	void dynamic_irq_cleanup(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, desc_node(desc));
	raw_spin_unlock_irqrestore(&desc->lock, flags);
	}

	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;
	}

	#ifdef CONFIG_GENERIC_HARDIRQS
	unsigned int kstat_irqs(unsigned int irq)
	{
	struct irq_desc *desc = irq_to_desc(irq);
	int cpu;
	int sum = 0;

	if (!desc \|\| !desc->kstat_irqs)
	return 0;
	for_each_possible_cpu(cpu)
	sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
	return sum;
	}
	#endif /* CONFIG_GENERIC_HARDIRQS */