[mirror_ubuntu-zesty-kernel.git] / drivers / w1 / w1_family.c

/*
 *	w1_family.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sched.h>	/* schedule_timeout() */
#include <linux/delay.h>

#include "w1_family.h"
#include "w1.h"

DEFINE_SPINLOCK(w1_flock);
static LIST_HEAD(w1_families);

int w1_register_family(struct w1_family *newf)
{
	struct list_head *ent, *n;
	struct w1_family *f;
	int ret = 0;

	spin_lock(&w1_flock);
	list_for_each_safe(ent, n, &w1_families) {
		f = list_entry(ent, struct w1_family, family_entry);

		if (f->fid == newf->fid) {
			ret = -EEXIST;
			break;
		}
	}

	if (!ret) {
		atomic_set(&newf->refcnt, 0);
		newf->need_exit = 0;
		list_add_tail(&newf->family_entry, &w1_families);
	}
	spin_unlock(&w1_flock);

	w1_reconnect_slaves(newf);

	return ret;
}

void w1_unregister_family(struct w1_family *fent)
{
	struct list_head *ent, *n;
	struct w1_family *f;

	spin_lock(&w1_flock);
	list_for_each_safe(ent, n, &w1_families) {
		f = list_entry(ent, struct w1_family, family_entry);

		if (f->fid == fent->fid) {
			list_del(&fent->family_entry);
			break;
		}
	}

	fent->need_exit = 1;

	spin_unlock(&w1_flock);

	while (atomic_read(&fent->refcnt)) {
		printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
				fent->fid, atomic_read(&fent->refcnt));

		if (msleep_interruptible(1000))
			flush_signals(current);
	}
}

/*
 * Should be called under w1_flock held.
 */
struct w1_family * w1_family_registered(u8 fid)
{
	struct list_head *ent, *n;
	struct w1_family *f = NULL;
	int ret = 0;

	list_for_each_safe(ent, n, &w1_families) {
		f = list_entry(ent, struct w1_family, family_entry);

		if (f->fid == fid) {
			ret = 1;
			break;
		}
	}

	return (ret) ? f : NULL;
}

static void __w1_family_put(struct w1_family *f)
{
	if (atomic_dec_and_test(&f->refcnt))
		f->need_exit = 1;
}

void w1_family_put(struct w1_family *f)
{
	spin_lock(&w1_flock);
	__w1_family_put(f);
	spin_unlock(&w1_flock);
}

#if 0
void w1_family_get(struct w1_family *f)
{
	spin_lock(&w1_flock);
	__w1_family_get(f);
	spin_unlock(&w1_flock);
}
#endif  /*  0  */

void __w1_family_get(struct w1_family *f)
{
	smp_mb__before_atomic_inc();
	atomic_inc(&f->refcnt);
	smp_mb__after_atomic_inc();
}

EXPORT_SYMBOL(w1_unregister_family);
EXPORT_SYMBOL(w1_register_family);
Commit	Line	Data
1da177e4	1	/*
7785925d	2	* w1_family.c
1da177e4 LT	3	*
1da177e4 LT	4	* Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
7785925d	5	*
1da177e4 LT	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/spinlock.h>
	23	#include <linux/list.h>
4e57b681	24	#include <linux/sched.h> /* schedule_timeout() */
1da177e4 LT	25	#include <linux/delay.h>
	26
	27	#include "w1_family.h"
a9fb1c7b	28	#include "w1.h"
1da177e4 LT	29
	30	DEFINE_SPINLOCK(w1_flock);
	31	static LIST_HEAD(w1_families);
	32
1da177e4 LT	33	int w1_register_family(struct w1_family *newf)
	34	{
	35	struct list_head ent, n;
	36	struct w1_family *f;
	37	int ret = 0;
	38
1da177e4 LT	39	spin_lock(&w1_flock);
	40	list_for_each_safe(ent, n, &w1_families) {
	41	f = list_entry(ent, struct w1_family, family_entry);
	42
	43	if (f->fid == newf->fid) {
	44	ret = -EEXIST;
	45	break;
	46	}
	47	}
	48
	49	if (!ret) {
	50	atomic_set(&newf->refcnt, 0);
	51	newf->need_exit = 0;
	52	list_add_tail(&newf->family_entry, &w1_families);
	53	}
1da177e4 LT	54	spin_unlock(&w1_flock);
1da177e4 LT	55
6adf87bd EP	56	w1_reconnect_slaves(newf);
6adf87bd EP	57
1da177e4 LT	58	return ret;
	59	}
	60
	61	void w1_unregister_family(struct w1_family *fent)
	62	{
	63	struct list_head ent, n;
	64	struct w1_family *f;
	65
	66	spin_lock(&w1_flock);
	67	list_for_each_safe(ent, n, &w1_families) {
	68	f = list_entry(ent, struct w1_family, family_entry);
	69
	70	if (f->fid == fent->fid) {
	71	list_del(&fent->family_entry);
	72	break;
	73	}
	74	}
	75
	76	fent->need_exit = 1;
	77
	78	spin_unlock(&w1_flock);
	79
	80	while (atomic_read(&fent->refcnt)) {
	81	printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
	82	fent->fid, atomic_read(&fent->refcnt));
	83
	84	if (msleep_interruptible(1000))
	85	flush_signals(current);
	86	}
	87	}
	88
	89	/*
	90	* Should be called under w1_flock held.
	91	*/
	92	struct w1_family * w1_family_registered(u8 fid)
	93	{
	94	struct list_head ent, n;
	95	struct w1_family *f = NULL;
	96	int ret = 0;
	97
	98	list_for_each_safe(ent, n, &w1_families) {
	99	f = list_entry(ent, struct w1_family, family_entry);
	100
	101	if (f->fid == fid) {
	102	ret = 1;
	103	break;
	104	}
	105	}
	106
	107	return (ret) ? f : NULL;
	108	}
	109
70d484bf EP	110	static void __w1_family_put(struct w1_family *f)
	111	{
	112	if (atomic_dec_and_test(&f->refcnt))
	113	f->need_exit = 1;
	114	}
	115
1da177e4 LT	116	void w1_family_put(struct w1_family *f)
	117	{
	118	spin_lock(&w1_flock);
	119	__w1_family_put(f);
	120	spin_unlock(&w1_flock);
	121	}
	122
70d484bf	123	#if 0
1da177e4 LT	124	void w1_family_get(struct w1_family *f)
	125	{
	126	spin_lock(&w1_flock);
	127	__w1_family_get(f);
	128	spin_unlock(&w1_flock);
1da177e4	129	}
70d484bf	130	#endif /* 0 */
1da177e4 LT	131
	132	void __w1_family_get(struct w1_family *f)
	133	{
	134	smp_mb__before_atomic_inc();
	135	atomic_inc(&f->refcnt);
	136	smp_mb__after_atomic_inc();
	137	}
	138
1da177e4 LT	139	EXPORT_SYMBOL(w1_unregister_family);
1da177e4 LT	140	EXPORT_SYMBOL(w1_register_family);