[net-next-2.6.git] / drivers / base / map.c

/*
 *  linux/drivers/base/map.c
 *
 * (C) Copyright Al Viro 2002,2003
 *	Released under GPL v2.
 *
 * NOTE: data structure needs to be changed.  It works, but for large dev_t
 * it will be too slow.  It is isolated, though, so these changes will be
 * local to that file.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/kdev_t.h>
#include <linux/kobject.h>
#include <linux/kobj_map.h>

struct kobj_map {
	struct probe {
		struct probe *next;
		dev_t dev;
		unsigned long range;
		struct module *owner;
		kobj_probe_t *get;
		int (*lock)(dev_t, void *);
		void *data;
	} *probes[255];
	struct mutex *lock;
};

int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
	     struct module *module, kobj_probe_t *probe,
	     int (*lock)(dev_t, void *), void *data)
{
	unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
	unsigned index = MAJOR(dev);
	unsigned i;
	struct probe *p;

	if (n > 255)
		n = 255;

	p = kmalloc(sizeof(struct probe) * n, GFP_KERNEL);

	if (p == NULL)
		return -ENOMEM;

	for (i = 0; i < n; i++, p++) {
		p->owner = module;
		p->get = probe;
		p->lock = lock;
		p->dev = dev;
		p->range = range;
		p->data = data;
	}
	mutex_lock(domain->lock);
	for (i = 0, p -= n; i < n; i++, p++, index++) {
		struct probe **s = &domain->probes[index % 255];
		while (*s && (*s)->range < range)
			s = &(*s)->next;
		p->next = *s;
		*s = p;
	}
	mutex_unlock(domain->lock);
	return 0;
}

void kobj_unmap(struct kobj_map *domain, dev_t dev, unsigned long range)
{
	unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
	unsigned index = MAJOR(dev);
	unsigned i;
	struct probe *found = NULL;

	if (n > 255)
		n = 255;

	mutex_lock(domain->lock);
	for (i = 0; i < n; i++, index++) {
		struct probe **s;
		for (s = &domain->probes[index % 255]; *s; s = &(*s)->next) {
			struct probe *p = *s;
			if (p->dev == dev && p->range == range) {
				*s = p->next;
				if (!found)
					found = p;
				break;
			}
		}
	}
	mutex_unlock(domain->lock);
	kfree(found);
}

struct kobject *kobj_lookup(struct kobj_map *domain, dev_t dev, int *index)
{
	struct kobject *kobj;
	struct probe *p;
	unsigned long best = ~0UL;

retry:
	mutex_lock(domain->lock);
	for (p = domain->probes[MAJOR(dev) % 255]; p; p = p->next) {
		struct kobject *(*probe)(dev_t, int *, void *);
		struct module *owner;
		void *data;

		if (p->dev > dev || p->dev + p->range - 1 < dev)
			continue;
		if (p->range - 1 >= best)
			break;
		if (!try_module_get(p->owner))
			continue;
		owner = p->owner;
		data = p->data;
		probe = p->get;
		best = p->range - 1;
		*index = dev - p->dev;
		if (p->lock && p->lock(dev, data) < 0) {
			module_put(owner);
			continue;
		}
		mutex_unlock(domain->lock);
		kobj = probe(dev, index, data);
		/* Currently ->owner protects _only_ ->probe() itself. */
		module_put(owner);
		if (kobj)
			return kobj;
		goto retry;
	}
	mutex_unlock(domain->lock);
	return NULL;
}

struct kobj_map *kobj_map_init(kobj_probe_t *base_probe, struct mutex *lock)
{
	struct kobj_map *p = kmalloc(sizeof(struct kobj_map), GFP_KERNEL);
	struct probe *base = kzalloc(sizeof(*base), GFP_KERNEL);
	int i;

	if ((p == NULL) || (base == NULL)) {
		kfree(p);
		kfree(base);
		return NULL;
	}

	base->dev = 1;
	base->range = ~0;
	base->get = base_probe;
	for (i = 0; i < 255; i++)
		p->probes[i] = base;
	p->lock = lock;
	return p;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/base/map.c
	3	*
	4	* (C) Copyright Al Viro 2002,2003
	5	* Released under GPL v2.
	6	*
	7	* NOTE: data structure needs to be changed. It works, but for large dev_t
	8	* it will be too slow. It is isolated, though, so these changes will be
	9	* local to that file.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/slab.h>
58383af6	14	#include <linux/mutex.h>
1da177e4 LT	15	#include <linux/kdev_t.h>
	16	#include <linux/kobject.h>
	17	#include <linux/kobj_map.h>
	18
	19	struct kobj_map {
	20	struct probe {
	21	struct probe *next;
	22	dev_t dev;
	23	unsigned long range;
	24	struct module *owner;
	25	kobj_probe_t *get;
	26	int (lock)(dev_t, void );
	27	void *data;
	28	} *probes[255];
58383af6	29	struct mutex *lock;
1da177e4 LT	30	};
	31
	32	int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
	33	struct module module, kobj_probe_t probe,
	34	int (lock)(dev_t, void ), void *data)
	35	{
	36	unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
	37	unsigned index = MAJOR(dev);
	38	unsigned i;
	39	struct probe *p;
	40
	41	if (n > 255)
	42	n = 255;
	43
	44	p = kmalloc(sizeof(struct probe) * n, GFP_KERNEL);
	45
	46	if (p == NULL)
	47	return -ENOMEM;
	48
	49	for (i = 0; i < n; i++, p++) {
	50	p->owner = module;
	51	p->get = probe;
	52	p->lock = lock;
	53	p->dev = dev;
	54	p->range = range;
	55	p->data = data;
	56	}
58383af6	57	mutex_lock(domain->lock);
1da177e4 LT	58	for (i = 0, p -= n; i < n; i++, p++, index++) {
	59	struct probe **s = &domain->probes[index % 255];
	60	while (s && (s)->range < range)
	61	s = &(*s)->next;
	62	p->next = *s;
	63	*s = p;
	64	}
58383af6	65	mutex_unlock(domain->lock);
1da177e4 LT	66	return 0;
	67	}
	68
	69	void kobj_unmap(struct kobj_map *domain, dev_t dev, unsigned long range)
	70	{
	71	unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
	72	unsigned index = MAJOR(dev);
	73	unsigned i;
	74	struct probe *found = NULL;
	75
	76	if (n > 255)
	77	n = 255;
	78
58383af6	79	mutex_lock(domain->lock);
1da177e4 LT	80	for (i = 0; i < n; i++, index++) {
	81	struct probe **s;
	82	for (s = &domain->probes[index % 255]; s; s = &(s)->next) {
	83	struct probe p = s;
	84	if (p->dev == dev && p->range == range) {
	85	*s = p->next;
	86	if (!found)
	87	found = p;
	88	break;
	89	}
	90	}
	91	}
58383af6	92	mutex_unlock(domain->lock);
1da177e4 LT	93	kfree(found);
	94	}
	95
	96	struct kobject kobj_lookup(struct kobj_map domain, dev_t dev, int *index)
	97	{
	98	struct kobject *kobj;
	99	struct probe *p;
	100	unsigned long best = ~0UL;
	101
	102	retry:
58383af6	103	mutex_lock(domain->lock);
1da177e4 LT	104	for (p = domain->probes[MAJOR(dev) % 255]; p; p = p->next) {
	105	struct kobject (probe)(dev_t, int , void );
	106	struct module *owner;
	107	void *data;
	108
	109	if (p->dev > dev \|\| p->dev + p->range - 1 < dev)
	110	continue;
	111	if (p->range - 1 >= best)
	112	break;
	113	if (!try_module_get(p->owner))
	114	continue;
	115	owner = p->owner;
	116	data = p->data;
	117	probe = p->get;
	118	best = p->range - 1;
	119	*index = dev - p->dev;
	120	if (p->lock && p->lock(dev, data) < 0) {
	121	module_put(owner);
	122	continue;
	123	}
58383af6	124	mutex_unlock(domain->lock);
1da177e4 LT	125	kobj = probe(dev, index, data);
	126	/* Currently ->owner protects _only_ ->probe() itself. */
	127	module_put(owner);
	128	if (kobj)
	129	return kobj;
	130	goto retry;
	131	}
58383af6	132	mutex_unlock(domain->lock);
1da177e4 LT	133	return NULL;
	134	}
	135
58383af6	136	struct kobj_map kobj_map_init(kobj_probe_t base_probe, struct mutex *lock)
1da177e4 LT	137	{
1da177e4 LT	138	struct kobj_map *p = kmalloc(sizeof(struct kobj_map), GFP_KERNEL);
4aed0644	139	struct probe base = kzalloc(sizeof(base), GFP_KERNEL);
1da177e4 LT	140	int i;
	141
	142	if ((p == NULL) \|\| (base == NULL)) {
	143	kfree(p);
	144	kfree(base);
	145	return NULL;
	146	}
	147
1da177e4 LT	148	base->dev = 1;
	149	base->range = ~0;
	150	base->get = base_probe;
	151	for (i = 0; i < 255; i++)
	152	p->probes[i] = base;
58383af6	153	p->lock = lock;
1da177e4 LT	154	return p;
1da177e4 LT	155	}