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-rw-r--r--include/linux/module.h4
-rw-r--r--kernel/module.c79
2 files changed, 51 insertions, 32 deletions
diff --git a/include/linux/module.h b/include/linux/module.h
index 6914fca..680db9e 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -359,7 +359,9 @@ struct module
#ifdef CONFIG_MODULE_UNLOAD
/* What modules depend on me? */
- struct list_head modules_which_use_me;
+ struct list_head source_list;
+ /* What modules do I depend on? */
+ struct list_head target_list;
/* Who is waiting for us to be unloaded */
struct task_struct *waiter;
diff --git a/kernel/module.c b/kernel/module.c
index 0129769..be18c3e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -523,7 +523,8 @@ static void module_unload_init(struct module *mod)
{
int cpu;
- INIT_LIST_HEAD(&mod->modules_which_use_me);
+ INIT_LIST_HEAD(&mod->source_list);
+ INIT_LIST_HEAD(&mod->target_list);
for_each_possible_cpu(cpu) {
per_cpu_ptr(mod->refptr, cpu)->incs = 0;
per_cpu_ptr(mod->refptr, cpu)->decs = 0;
@@ -538,8 +539,9 @@ static void module_unload_init(struct module *mod)
/* modules using other modules */
struct module_use
{
- struct list_head list;
- struct module *module_which_uses;
+ struct list_head source_list;
+ struct list_head target_list;
+ struct module *source, *target;
};
/* Does a already use b? */
@@ -547,8 +549,8 @@ static int already_uses(struct module *a, struct module *b)
{
struct module_use *use;
- list_for_each_entry(use, &b->modules_which_use_me, list) {
- if (use->module_which_uses == a) {
+ list_for_each_entry(use, &b->source_list, source_list) {
+ if (use->source == a) {
DEBUGP("%s uses %s!\n", a->name, b->name);
return 1;
}
@@ -557,6 +559,33 @@ static int already_uses(struct module *a, struct module *b)
return 0;
}
+/*
+ * Module a uses b
+ * - we add 'a' as a "source", 'b' as a "target" of module use
+ * - the module_use is added to the list of 'b' sources (so
+ * 'b' can walk the list to see who sourced them), and of 'a'
+ * targets (so 'a' can see what modules it targets).
+ */
+static int add_module_usage(struct module *a, struct module *b)
+{
+ int no_warn;
+ struct module_use *use;
+
+ DEBUGP("Allocating new usage for %s.\n", a->name);
+ use = kmalloc(sizeof(*use), GFP_ATOMIC);
+ if (!use) {
+ printk(KERN_WARNING "%s: out of memory loading\n", a->name);
+ return -ENOMEM;
+ }
+
+ use->source = a;
+ use->target = b;
+ list_add(&use->source_list, &b->source_list);
+ list_add(&use->target_list, &a->target_list);
+ no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
+ return 0;
+}
+
/* Module a uses b */
int use_module(struct module *a, struct module *b)
{
@@ -578,17 +607,11 @@ int use_module(struct module *a, struct module *b)
if (err)
return 0;
- DEBUGP("Allocating new usage for %s.\n", a->name);
- use = kmalloc(sizeof(*use), GFP_ATOMIC);
- if (!use) {
- printk("%s: out of memory loading\n", a->name);
+ err = add_module_usage(a, b);
+ if (err) {
module_put(b);
return 0;
}
-
- use->module_which_uses = a;
- list_add(&use->list, &b->modules_which_use_me);
- no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
return 1;
}
EXPORT_SYMBOL_GPL(use_module);
@@ -596,22 +619,16 @@ EXPORT_SYMBOL_GPL(use_module);
/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
- struct module *i;
-
- list_for_each_entry(i, &modules, list) {
- struct module_use *use;
+ struct module_use *use, *tmp;
- list_for_each_entry(use, &i->modules_which_use_me, list) {
- if (use->module_which_uses == mod) {
- DEBUGP("%s unusing %s\n", mod->name, i->name);
- module_put(i);
- list_del(&use->list);
- kfree(use);
- sysfs_remove_link(i->holders_dir, mod->name);
- /* There can be at most one match. */
- break;
- }
- }
+ list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
+ struct module *i = use->target;
+ DEBUGP("%s unusing %s\n", mod->name, i->name);
+ module_put(i);
+ list_del(&use->source_list);
+ list_del(&use->target_list);
+ kfree(use);
+ sysfs_remove_link(i->holders_dir, mod->name);
}
}
@@ -735,7 +752,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
goto out;
}
- if (!list_empty(&mod->modules_which_use_me)) {
+ if (!list_empty(&mod->source_list)) {
/* Other modules depend on us: get rid of them first. */
ret = -EWOULDBLOCK;
goto out;
@@ -799,9 +816,9 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
/* Always include a trailing , so userspace can differentiate
between this and the old multi-field proc format. */
- list_for_each_entry(use, &mod->modules_which_use_me, list) {
+ list_for_each_entry(use, &mod->source_list, source_list) {
printed_something = 1;
- seq_printf(m, "%s,", use->module_which_uses->name);
+ seq_printf(m, "%s,", use->source->name);
}
if (mod->init != NULL && mod->exit == NULL) {
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