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1da177e4 LT |
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 = kmalloc(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 | memset(ime_new, 0, sizeof(*ime_new)); | |
51 | ime_new->im_name = im_name; | |
52 | ime_new->owner = owner; | |
53 | ime_new->userdata = userdata; | |
54 | ||
55 | spin_lock(&ime_lock); | |
56 | list_for_each(tmp, &ime_list) { | |
57 | ime = list_entry(tmp, struct inter_module_entry, list); | |
58 | if (strcmp(ime->im_name, im_name) == 0) { | |
59 | spin_unlock(&ime_lock); | |
60 | kfree(ime_new); | |
61 | /* Program logic error, fatal */ | |
62 | printk(KERN_ERR "inter_module_register: duplicate im_name '%s'", im_name); | |
63 | BUG(); | |
64 | } | |
65 | } | |
66 | list_add(&(ime_new->list), &ime_list); | |
67 | spin_unlock(&ime_lock); | |
68 | } | |
69 | ||
70 | /** | |
71 | * inter_module_unregister - unregister a set of inter module data. | |
72 | * @im_name: an arbitrary string to identify the data, must be unique | |
73 | * | |
74 | * Description: Check that the im_name has been registered, complain if | |
75 | * it has not. For existing data, remove it from the | |
76 | * inter_module_entry list. | |
77 | */ | |
78 | void inter_module_unregister(const char *im_name) | |
79 | { | |
80 | struct list_head *tmp; | |
81 | struct inter_module_entry *ime; | |
82 | ||
83 | spin_lock(&ime_lock); | |
84 | list_for_each(tmp, &ime_list) { | |
85 | ime = list_entry(tmp, struct inter_module_entry, list); | |
86 | if (strcmp(ime->im_name, im_name) == 0) { | |
87 | list_del(&(ime->list)); | |
88 | spin_unlock(&ime_lock); | |
89 | kfree(ime); | |
90 | return; | |
91 | } | |
92 | } | |
93 | spin_unlock(&ime_lock); | |
94 | if (kmalloc_failed) { | |
95 | printk(KERN_ERR | |
96 | "inter_module_unregister: no entry for '%s', " | |
97 | "probably caused by previous kmalloc failure\n", | |
98 | im_name); | |
99 | return; | |
100 | } | |
101 | else { | |
102 | /* Program logic error, fatal */ | |
103 | printk(KERN_ERR "inter_module_unregister: no entry for '%s'", im_name); | |
104 | BUG(); | |
105 | } | |
106 | } | |
107 | ||
108 | /** | |
109 | * inter_module_get - return arbitrary userdata from another module. | |
110 | * @im_name: an arbitrary string to identify the data, must be unique | |
111 | * | |
112 | * Description: If the im_name has not been registered, return NULL. | |
113 | * Try to increment the use count on the owning module, if that fails | |
114 | * then return NULL. Otherwise return the userdata. | |
115 | */ | |
116 | static const void *inter_module_get(const char *im_name) | |
117 | { | |
118 | struct list_head *tmp; | |
119 | struct inter_module_entry *ime; | |
120 | const void *result = NULL; | |
121 | ||
122 | spin_lock(&ime_lock); | |
123 | list_for_each(tmp, &ime_list) { | |
124 | ime = list_entry(tmp, struct inter_module_entry, list); | |
125 | if (strcmp(ime->im_name, im_name) == 0) { | |
126 | if (try_module_get(ime->owner)) | |
127 | result = ime->userdata; | |
128 | break; | |
129 | } | |
130 | } | |
131 | spin_unlock(&ime_lock); | |
132 | return(result); | |
133 | } | |
134 | ||
135 | /** | |
136 | * inter_module_get_request - im get with automatic request_module. | |
137 | * @im_name: an arbitrary string to identify the data, must be unique | |
138 | * @modname: module that is expected to register im_name | |
139 | * | |
140 | * Description: If inter_module_get fails, do request_module then retry. | |
141 | */ | |
142 | const void *inter_module_get_request(const char *im_name, const char *modname) | |
143 | { | |
144 | const void *result = inter_module_get(im_name); | |
145 | if (!result) { | |
146 | request_module("%s", modname); | |
147 | result = inter_module_get(im_name); | |
148 | } | |
149 | return(result); | |
150 | } | |
151 | ||
152 | /** | |
153 | * inter_module_put - release use of data from another module. | |
154 | * @im_name: an arbitrary string to identify the data, must be unique | |
155 | * | |
156 | * Description: If the im_name has not been registered, complain, | |
157 | * otherwise decrement the use count on the owning module. | |
158 | */ | |
159 | void inter_module_put(const char *im_name) | |
160 | { | |
161 | struct list_head *tmp; | |
162 | struct inter_module_entry *ime; | |
163 | ||
164 | spin_lock(&ime_lock); | |
165 | list_for_each(tmp, &ime_list) { | |
166 | ime = list_entry(tmp, struct inter_module_entry, list); | |
167 | if (strcmp(ime->im_name, im_name) == 0) { | |
168 | if (ime->owner) | |
169 | module_put(ime->owner); | |
170 | spin_unlock(&ime_lock); | |
171 | return; | |
172 | } | |
173 | } | |
174 | spin_unlock(&ime_lock); | |
175 | printk(KERN_ERR "inter_module_put: no entry for '%s'", im_name); | |
176 | BUG(); | |
177 | } | |
178 | ||
179 | EXPORT_SYMBOL(inter_module_register); | |
180 | EXPORT_SYMBOL(inter_module_unregister); | |
181 | EXPORT_SYMBOL(inter_module_get_request); | |
182 | EXPORT_SYMBOL(inter_module_put); |