/* Deprecated, do not use. Moved from module.c to here. --RR */
/* Written by Keith Owens <kaos@ocs.com.au> Oct 2000 */
#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/slab.h>
/* inter_module functions are always available, even when the kernel is
* compiled without modules. Consumers of inter_module_xxx routines
* will always work, even when both are built into the kernel, this
* approach removes lots of #ifdefs in mainline code.
*/
static struct list_head ime_list = LIST_HEAD_INIT(ime_list);
static DEFINE_SPINLOCK(ime_lock);
static int kmalloc_failed;
struct inter_module_entry {
struct list_head list;
const char *im_name;
struct module *owner;
const void *userdata;
};
/**
* inter_module_register - register a new set of inter module data.
* @im_name: an arbitrary string to identify the data, must be unique
* @owner: module that is registering the data, always use THIS_MODULE
* @userdata: pointer to arbitrary userdata to be registered
*
* Description: Check that the im_name has not already been registered,
* complain if it has. For new data, add it to the inter_module_entry
* list.
*/
void inter_module_register(const char *im_name, struct module *owner, const void *userdata)
{
struct list_head *tmp;
struct inter_module_entry *ime, *ime_new;
if (!(ime_new = kzalloc(sizeof(*ime), GFP_KERNEL))) {
/* Overloaded kernel, not fatal */
printk(KERN_ERR
"Aiee, inter_module_register: cannot kmalloc entry for '%s'\n",
im_name);
kmalloc_failed = 1;
return;
}
ime_new->im_name = im_name;
ime_new->owner = owner;
ime_new->userdata = userdata;
spin_lock(&ime_lock);
list_for_each(tmp, &ime_list) {
ime = list_entry(tmp, struct inter_module_entry, list);
if (strcmp(ime->im_name, im_name) == 0) {
spin_unlock(&ime_lock);
kfree(ime_new);
/* Program logic error, fatal */
printk(KERN_ERR "inter_module_register: duplicate im_name '%s'", im_name);
BUG();
}
}
list_add(&(ime_new->list), &ime_list);
spin_unlock(&ime_lock);
}
/**
* inter_module_unregister - unregister a set of inter module data.
* @im_name: an arbitrary string to identify the data, must be unique
*
* Description: Check that the im_name has been registered, complain if
* it has not. For existing data, remove it from the
* inter_module_entry list.
*/
void inter_module_unregister(const char *im_name)
{
struct list_head *tmp;
struct inter_module_entry *ime;
spin_lock(&ime_lock);
list_for_each(tmp, &ime_list) {
ime = list_entry(tmp, struct inter_module_entry, list);
if (strcmp(ime->im_name, im_name) == 0) {
list_del(&(ime->list));
spin_unlock(&ime_lock);
kfree(ime);
return;
}
}
spin_unlock(&ime_lock);
if (kmalloc_failed) {
printk(KERN_ERR
"inter_module_unregister: no entry for '%s', "
"probably caused by previous kmalloc failure\n",
im_name);
return;
}
else {
/* Program logic error, fatal */
printk(KERN_ERR "inter_module_unregister: no entry for '%s'", im_name);
BUG();
}
}
/**
* inter_module_get - return arbitrary userdata from another module.
* @im_name: an arbitrary string to identify the data, must be unique
*
* Description: If the im_name has not been registered, return NULL.
* Try to increment the use count on the owning module, if that fails
* then return NULL. Otherwise return the userdata.
*/
static const void *inter_module_get(const char *im_name)
{
struct list_head *tmp;
struct inter_module_entry *ime;
const void *result = NULL;
spin_lock(&ime_lock);
list_for_each(tmp, &ime_list) {
ime = list_entry(tmp, struct inter_module_entry, list);
if (strcmp(ime->im_name, im_name) == 0) {
if (try_module_get(ime->owner))
result = ime->userdata;
break;
}
}
spin_unlock(&ime_lock);
return(result);
}
/**
* inter_module_get_request - im get with automatic request_module.
* @im_name: an arbitrary string to identify the data, must be unique
* @modname: module that is expected to register im_name
*
* Description: If inter_module_get fails, do request_module then retry.
*/
const void *inter_module_get_request(const char *im_name, const char *modname)
{
const void *result = inter_module_get(im_name);
if (!result) {
request_module("%s", modname);
result = inter_module_get(im_name);
}
return(result);
}
/**
* inter_module_put - release use of data from another module.
* @im_name: an arbitrary string to identify the data, must be unique
*
* Description: If the im_name has not been registered, complain,
* otherwise decrement the use count on the owning module.
*/
void inter_module_put(const char *im_name)
{
struct list_head *tmp;
struct inter_module_entry *ime;
spin_lock(&ime_lock);
list_for_each(tmp, &ime_list) {
ime = list_entry(tmp, struct inter_module_entry, list);
if (strcmp(ime->im_name, im_name) == 0) {
if (ime->owner)
module_put(ime->owner);
spin_unlock(&ime_lock);
return;
}
}
spin_unlock(&ime_lock);
printk(KERN_ERR "inter_module_put: no entry for '%s'", im_name);
BUG();
}
EXPORT_SYMBOL(inter_module_register);
EXPORT_SYMBOL(inter_module_unregister);
EXPORT_SYMBOL(inter_module_get_request);
EXPORT_SYMBOL(inter_module_put);
MODULE_LICENSE("GPL");
