diff options
Diffstat (limited to 'kernel/intermodule.c')
| -rw-r--r-- | kernel/intermodule.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/kernel/intermodule.c b/kernel/intermodule.c new file mode 100644 index 000000000000..388977f3e9b7 --- /dev/null +++ b/kernel/intermodule.c @@ -0,0 +1,182 @@ +/* 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 = kmalloc(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; + } + memset(ime_new, 0, sizeof(*ime_new)); + 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); |