1 /* Deprecated, do not use. Moved from module.c to here. --RR */
2
3 /* Written by Keith Owens <kaos@ocs.com.au> Oct 2000 */
4 #include <linux/module.h>
5 #include <linux/kmod.h>
6 #include <linux/spinlock.h>
7 #include <linux/list.h>
8 #include <linux/slab.h>
9
10 /* inter_module functions are always available, even when the kernel is
11 * compiled without modules. Consumers of inter_module_xxx routines
12 * will always work, even when both are built into the kernel, this
13 * approach removes lots of #ifdefs in mainline code.
14 */
15
16 static struct list_head ime_list = LIST_HEAD_INIT(ime_list);
17 static DEFINE_SPINLOCK(ime_lock);
18 static int kmalloc_failed;
19
20 struct inter_module_entry {
21 struct list_head list;
22 const char *im_name;
23 struct module *owner;
24 const void *userdata;
25 };
26
27 /**
28 * inter_module_register - register a new set of inter module data.
29 * @im_name: an arbitrary string to identify the data, must be unique
30 * @owner: module that is registering the data, always use THIS_MODULE
31 * @userdata: pointer to arbitrary userdata to be registered
32 *
33 * Description: Check that the im_name has not already been registered,
34 * complain if it has. For new data, add it to the inter_module_entry
35 * list.
36 */
37 void inter_module_register(const char *im_name, struct module *owner, const void *userdata)
38 {
39 struct list_head *tmp;
40 struct inter_module_entry *ime, *ime_new;
41
42 if (!(ime_new = kzalloc(sizeof(*ime), GFP_KERNEL))) {
43 /* Overloaded kernel, not fatal */
44 printk(KERN_ERR
45 "Aiee, inter_module_register: cannot kmalloc entry for '%s'\n",
46 im_name);
47 kmalloc_failed = 1;
48 return;
49 }
50 ime_new->im_name = im_name;
51 ime_new->owner = owner;
52 ime_new->userdata = userdata;
53
54 spin_lock(&ime_lock);
55 list_for_each(tmp, &ime_list) {
56 ime = list_entry(tmp, struct inter_module_entry, list);
57 if (strcmp(ime->im_name, im_name) == 0) {
58 spin_unlock(&ime_lock);
59 kfree(ime_new);
60 /* Program logic error, fatal */
61 printk(KERN_ERR "inter_module_register: duplicate im_name '%s'", im_name);
62 BUG();
63 }
64 }
65 list_add(&(ime_new->list), &ime_list);
66 spin_unlock(&ime_lock);
67 }
68
69 /**
70 * inter_module_unregister - unregister a set of inter module data.
71 * @im_name: an arbitrary string to identify the data, must be unique
72 *
73 * Description: Check that the im_name has been registered, complain if
74 * it has not. For existing data, remove it from the
75 * inter_module_entry list.
76 */
77 void inter_module_unregister(const char *im_name)
78 {
79 struct list_head *tmp;
80 struct inter_module_entry *ime;
81
82 spin_lock(&ime_lock);
83 list_for_each(tmp, &ime_list) {
84 ime = list_entry(tmp, struct inter_module_entry, list);
85 if (strcmp(ime->im_name, im_name) == 0) {
86 list_del(&(ime->list));
87 spin_unlock(&ime_lock);
88 kfree(ime);
89 return;
90 }
91 }
92 spin_unlock(&ime_lock);
93 if (kmalloc_failed) {
94 printk(KERN_ERR
95 "inter_module_unregister: no entry for '%s', "
96 "probably caused by previous kmalloc failure\n",
97 im_name);
98 return;
99 }
100 else {
101 /* Program logic error, fatal */
102 printk(KERN_ERR "inter_module_unregister: no entry for '%s'", im_name);
103 BUG();
104 }
105 }
106
107 /**
108 * inter_module_get - return arbitrary userdata from another module.
109 * @im_name: an arbitrary string to identify the data, must be unique
110 *
111 * Description: If the im_name has not been registered, return NULL.
112 * Try to increment the use count on the owning module, if that fails
113 * then return NULL. Otherwise return the userdata.
114 */
115 static const void *inter_module_get(const char *im_name)
116 {
117 struct list_head *tmp;
118 struct inter_module_entry *ime;
119 const void *result = NULL;
120
121 spin_lock(&ime_lock);
122 list_for_each(tmp, &ime_list) {
123 ime = list_entry(tmp, struct inter_module_entry, list);
124 if (strcmp(ime->im_name, im_name) == 0) {
125 if (try_module_get(ime->owner))
126 result = ime->userdata;
127 break;
128 }
129 }
130 spin_unlock(&ime_lock);
131 return(result);
132 }
133
134 /**
135 * inter_module_get_request - im get with automatic request_module.
136 * @im_name: an arbitrary string to identify the data, must be unique
137 * @modname: module that is expected to register im_name
138 *
139 * Description: If inter_module_get fails, do request_module then retry.
140 */
141 const void *inter_module_get_request(const char *im_name, const char *modname)
142 {
143 const void *result = inter_module_get(im_name);
144 if (!result) {
145 request_module("%s", modname);
146 result = inter_module_get(im_name);
147 }
148 return(result);
149 }
150
151 /**
152 * inter_module_put - release use of data from another module.
153 * @im_name: an arbitrary string to identify the data, must be unique
154 *
155 * Description: If the im_name has not been registered, complain,
156 * otherwise decrement the use count on the owning module.
157 */
158 void inter_module_put(const char *im_name)
159 {
160 struct list_head *tmp;
161 struct inter_module_entry *ime;
162
163 spin_lock(&ime_lock);
164 list_for_each(tmp, &ime_list) {
165 ime = list_entry(tmp, struct inter_module_entry, list);
166 if (strcmp(ime->im_name, im_name) == 0) {
167 if (ime->owner)
168 module_put(ime->owner);
169 spin_unlock(&ime_lock);
170 return;
171 }
172 }
173 spin_unlock(&ime_lock);
174 printk(KERN_ERR "inter_module_put: no entry for '%s'", im_name);
175 BUG();
176 }
177
178 EXPORT_SYMBOL(inter_module_register);
179 EXPORT_SYMBOL(inter_module_unregister);
180 EXPORT_SYMBOL(inter_module_get_request);
181 EXPORT_SYMBOL(inter_module_put);
182
183 MODULE_LICENSE("GPL");
184
185
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