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> | |
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); |
55 | ||
6adf87bd EP |
56 | w1_reconnect_slaves(newf); |
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); |
140 | EXPORT_SYMBOL(w1_register_family); |