Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
7785925d | 2 | * w1_family.c |
1da177e4 LT |
3 | * |
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> | |
24 | #include <linux/delay.h> | |
25 | ||
26 | #include "w1_family.h" | |
27 | ||
28 | DEFINE_SPINLOCK(w1_flock); | |
29 | static LIST_HEAD(w1_families); | |
e5c515b4 | 30 | extern void w1_reconnect_slaves(struct w1_family *f); |
1da177e4 | 31 | |
1da177e4 LT |
32 | int w1_register_family(struct w1_family *newf) |
33 | { | |
34 | struct list_head *ent, *n; | |
35 | struct w1_family *f; | |
36 | int ret = 0; | |
37 | ||
1da177e4 LT |
38 | spin_lock(&w1_flock); |
39 | list_for_each_safe(ent, n, &w1_families) { | |
40 | f = list_entry(ent, struct w1_family, family_entry); | |
41 | ||
42 | if (f->fid == newf->fid) { | |
43 | ret = -EEXIST; | |
44 | break; | |
45 | } | |
46 | } | |
47 | ||
48 | if (!ret) { | |
49 | atomic_set(&newf->refcnt, 0); | |
50 | newf->need_exit = 0; | |
51 | list_add_tail(&newf->family_entry, &w1_families); | |
52 | } | |
1da177e4 LT |
53 | spin_unlock(&w1_flock); |
54 | ||
6adf87bd EP |
55 | w1_reconnect_slaves(newf); |
56 | ||
1da177e4 LT |
57 | return ret; |
58 | } | |
59 | ||
60 | void w1_unregister_family(struct w1_family *fent) | |
61 | { | |
62 | struct list_head *ent, *n; | |
63 | struct w1_family *f; | |
64 | ||
65 | spin_lock(&w1_flock); | |
66 | list_for_each_safe(ent, n, &w1_families) { | |
67 | f = list_entry(ent, struct w1_family, family_entry); | |
68 | ||
69 | if (f->fid == fent->fid) { | |
70 | list_del(&fent->family_entry); | |
71 | break; | |
72 | } | |
73 | } | |
74 | ||
75 | fent->need_exit = 1; | |
76 | ||
77 | spin_unlock(&w1_flock); | |
78 | ||
79 | while (atomic_read(&fent->refcnt)) { | |
80 | printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n", | |
81 | fent->fid, atomic_read(&fent->refcnt)); | |
82 | ||
83 | if (msleep_interruptible(1000)) | |
84 | flush_signals(current); | |
85 | } | |
86 | } | |
87 | ||
88 | /* | |
89 | * Should be called under w1_flock held. | |
90 | */ | |
91 | struct w1_family * w1_family_registered(u8 fid) | |
92 | { | |
93 | struct list_head *ent, *n; | |
94 | struct w1_family *f = NULL; | |
95 | int ret = 0; | |
96 | ||
97 | list_for_each_safe(ent, n, &w1_families) { | |
98 | f = list_entry(ent, struct w1_family, family_entry); | |
99 | ||
100 | if (f->fid == fid) { | |
101 | ret = 1; | |
102 | break; | |
103 | } | |
104 | } | |
105 | ||
106 | return (ret) ? f : NULL; | |
107 | } | |
108 | ||
109 | void w1_family_put(struct w1_family *f) | |
110 | { | |
111 | spin_lock(&w1_flock); | |
112 | __w1_family_put(f); | |
113 | spin_unlock(&w1_flock); | |
114 | } | |
115 | ||
116 | void __w1_family_put(struct w1_family *f) | |
117 | { | |
118 | if (atomic_dec_and_test(&f->refcnt)) | |
119 | f->need_exit = 1; | |
120 | } | |
121 | ||
122 | void w1_family_get(struct w1_family *f) | |
123 | { | |
124 | spin_lock(&w1_flock); | |
125 | __w1_family_get(f); | |
126 | spin_unlock(&w1_flock); | |
127 | ||
128 | } | |
129 | ||
130 | void __w1_family_get(struct w1_family *f) | |
131 | { | |
132 | smp_mb__before_atomic_inc(); | |
133 | atomic_inc(&f->refcnt); | |
134 | smp_mb__after_atomic_inc(); | |
135 | } | |
136 | ||
137 | EXPORT_SYMBOL(w1_family_get); | |
138 | EXPORT_SYMBOL(w1_family_put); | |
139 | EXPORT_SYMBOL(w1_family_registered); | |
140 | EXPORT_SYMBOL(w1_unregister_family); | |
141 | EXPORT_SYMBOL(w1_register_family); |