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22#include <linux/spinlock.h>
23#include <linux/list.h>
24#include <linux/sched.h>
25#include <linux/delay.h>
26#include <linux/export.h>
27
28#include "w1_family.h"
29#include "w1.h"
30
31DEFINE_SPINLOCK(w1_flock);
32static LIST_HEAD(w1_families);
33
34
35
36
37
38int w1_register_family(struct w1_family *newf)
39{
40 struct list_head *ent, *n;
41 struct w1_family *f;
42 int ret = 0;
43
44 spin_lock(&w1_flock);
45 list_for_each_safe(ent, n, &w1_families) {
46 f = list_entry(ent, struct w1_family, family_entry);
47
48 if (f->fid == newf->fid) {
49 ret = -EEXIST;
50 break;
51 }
52 }
53
54 if (!ret) {
55 atomic_set(&newf->refcnt, 0);
56 list_add_tail(&newf->family_entry, &w1_families);
57 }
58 spin_unlock(&w1_flock);
59
60
61 w1_reconnect_slaves(newf, 1);
62
63 return ret;
64}
65
66
67
68
69
70void w1_unregister_family(struct w1_family *fent)
71{
72 struct list_head *ent, *n;
73 struct w1_family *f;
74
75 spin_lock(&w1_flock);
76 list_for_each_safe(ent, n, &w1_families) {
77 f = list_entry(ent, struct w1_family, family_entry);
78
79 if (f->fid == fent->fid) {
80 list_del(&fent->family_entry);
81 break;
82 }
83 }
84 spin_unlock(&w1_flock);
85
86
87 w1_reconnect_slaves(fent, 0);
88
89 while (atomic_read(&fent->refcnt)) {
90 pr_info("Waiting for family %u to become free: refcnt=%d.\n",
91 fent->fid, atomic_read(&fent->refcnt));
92
93 if (msleep_interruptible(1000))
94 flush_signals(current);
95 }
96}
97
98
99
100
101struct w1_family * w1_family_registered(u8 fid)
102{
103 struct list_head *ent, *n;
104 struct w1_family *f = NULL;
105 int ret = 0;
106
107 list_for_each_safe(ent, n, &w1_families) {
108 f = list_entry(ent, struct w1_family, family_entry);
109
110 if (f->fid == fid) {
111 ret = 1;
112 break;
113 }
114 }
115
116 return (ret) ? f : NULL;
117}
118
119static void __w1_family_put(struct w1_family *f)
120{
121 atomic_dec(&f->refcnt);
122}
123
124void w1_family_put(struct w1_family *f)
125{
126 spin_lock(&w1_flock);
127 __w1_family_put(f);
128 spin_unlock(&w1_flock);
129}
130
131#if 0
132void w1_family_get(struct w1_family *f)
133{
134 spin_lock(&w1_flock);
135 __w1_family_get(f);
136 spin_unlock(&w1_flock);
137}
138#endif
139
140void __w1_family_get(struct w1_family *f)
141{
142 smp_mb__before_atomic();
143 atomic_inc(&f->refcnt);
144 smp_mb__after_atomic();
145}
146
147EXPORT_SYMBOL(w1_unregister_family);
148EXPORT_SYMBOL(w1_register_family);
149