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); | |
30 | ||
31 | static int w1_check_family(struct w1_family *f) | |
32 | { | |
ca775c62 | 33 | if (!f->fops->rname || !f->fops->rbin) |
1da177e4 LT |
34 | return -EINVAL; |
35 | ||
36 | return 0; | |
37 | } | |
38 | ||
39 | int w1_register_family(struct w1_family *newf) | |
40 | { | |
41 | struct list_head *ent, *n; | |
42 | struct w1_family *f; | |
43 | int ret = 0; | |
44 | ||
45 | if (w1_check_family(newf)) | |
46 | return -EINVAL; | |
47 | ||
48 | spin_lock(&w1_flock); | |
49 | list_for_each_safe(ent, n, &w1_families) { | |
50 | f = list_entry(ent, struct w1_family, family_entry); | |
51 | ||
52 | if (f->fid == newf->fid) { | |
53 | ret = -EEXIST; | |
54 | break; | |
55 | } | |
56 | } | |
57 | ||
58 | if (!ret) { | |
59 | atomic_set(&newf->refcnt, 0); | |
60 | newf->need_exit = 0; | |
61 | list_add_tail(&newf->family_entry, &w1_families); | |
62 | } | |
63 | ||
64 | spin_unlock(&w1_flock); | |
65 | ||
66 | return ret; | |
67 | } | |
68 | ||
69 | void w1_unregister_family(struct w1_family *fent) | |
70 | { | |
71 | struct list_head *ent, *n; | |
72 | struct w1_family *f; | |
73 | ||
74 | spin_lock(&w1_flock); | |
75 | list_for_each_safe(ent, n, &w1_families) { | |
76 | f = list_entry(ent, struct w1_family, family_entry); | |
77 | ||
78 | if (f->fid == fent->fid) { | |
79 | list_del(&fent->family_entry); | |
80 | break; | |
81 | } | |
82 | } | |
83 | ||
84 | fent->need_exit = 1; | |
85 | ||
86 | spin_unlock(&w1_flock); | |
87 | ||
88 | while (atomic_read(&fent->refcnt)) { | |
89 | printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n", | |
90 | fent->fid, atomic_read(&fent->refcnt)); | |
91 | ||
92 | if (msleep_interruptible(1000)) | |
93 | flush_signals(current); | |
94 | } | |
95 | } | |
96 | ||
97 | /* | |
98 | * Should be called under w1_flock held. | |
99 | */ | |
100 | struct w1_family * w1_family_registered(u8 fid) | |
101 | { | |
102 | struct list_head *ent, *n; | |
103 | struct w1_family *f = NULL; | |
104 | int ret = 0; | |
105 | ||
106 | list_for_each_safe(ent, n, &w1_families) { | |
107 | f = list_entry(ent, struct w1_family, family_entry); | |
108 | ||
109 | if (f->fid == fid) { | |
110 | ret = 1; | |
111 | break; | |
112 | } | |
113 | } | |
114 | ||
115 | return (ret) ? f : NULL; | |
116 | } | |
117 | ||
118 | void w1_family_put(struct w1_family *f) | |
119 | { | |
120 | spin_lock(&w1_flock); | |
121 | __w1_family_put(f); | |
122 | spin_unlock(&w1_flock); | |
123 | } | |
124 | ||
125 | void __w1_family_put(struct w1_family *f) | |
126 | { | |
127 | if (atomic_dec_and_test(&f->refcnt)) | |
128 | f->need_exit = 1; | |
129 | } | |
130 | ||
131 | void w1_family_get(struct w1_family *f) | |
132 | { | |
133 | spin_lock(&w1_flock); | |
134 | __w1_family_get(f); | |
135 | spin_unlock(&w1_flock); | |
136 | ||
137 | } | |
138 | ||
139 | void __w1_family_get(struct w1_family *f) | |
140 | { | |
141 | smp_mb__before_atomic_inc(); | |
142 | atomic_inc(&f->refcnt); | |
143 | smp_mb__after_atomic_inc(); | |
144 | } | |
145 | ||
146 | EXPORT_SYMBOL(w1_family_get); | |
147 | EXPORT_SYMBOL(w1_family_put); | |
148 | EXPORT_SYMBOL(w1_family_registered); | |
149 | EXPORT_SYMBOL(w1_unregister_family); | |
150 | EXPORT_SYMBOL(w1_register_family); |