blob: 9e293e139a0e8e05737ebf4d555116aef745c684 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Evgeniy Polyakov77859252005-05-20 22:33:25 +04002 * w1_family.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Evgeniy Polyakov77859252005-05-20 22:33:25 +04005 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
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>
Tim Schmielau4e57b682005-10-30 15:03:48 -080024#include <linux/sched.h> /* schedule_timeout() */
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/delay.h>
26
27#include "w1_family.h"
28
29DEFINE_SPINLOCK(w1_flock);
30static LIST_HEAD(w1_families);
Evgeniy Polyakove5c515b2005-06-10 14:53:22 +040031extern void w1_reconnect_slaves(struct w1_family *f);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Linus Torvalds1da177e2005-04-16 15:20:36 -070033int w1_register_family(struct w1_family *newf)
34{
35 struct list_head *ent, *n;
36 struct w1_family *f;
37 int ret = 0;
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 spin_unlock(&w1_flock);
55
Evgeniy Polyakov6adf87b2005-06-04 01:29:25 +040056 w1_reconnect_slaves(newf);
57
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 return ret;
59}
60
61void 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 */
92struct 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
110void w1_family_put(struct w1_family *f)
111{
112 spin_lock(&w1_flock);
113 __w1_family_put(f);
114 spin_unlock(&w1_flock);
115}
116
117void __w1_family_put(struct w1_family *f)
118{
119 if (atomic_dec_and_test(&f->refcnt))
120 f->need_exit = 1;
121}
122
123void w1_family_get(struct w1_family *f)
124{
125 spin_lock(&w1_flock);
126 __w1_family_get(f);
127 spin_unlock(&w1_flock);
128
129}
130
131void __w1_family_get(struct w1_family *f)
132{
133 smp_mb__before_atomic_inc();
134 atomic_inc(&f->refcnt);
135 smp_mb__after_atomic_inc();
136}
137
138EXPORT_SYMBOL(w1_family_get);
139EXPORT_SYMBOL(w1_family_put);
140EXPORT_SYMBOL(w1_family_registered);
141EXPORT_SYMBOL(w1_unregister_family);
142EXPORT_SYMBOL(w1_register_family);