module: move sysfs exposure to end of load_module

This means a little extra work, but is more logical: we don't put
anything in sysfs until we're about to put the module into the
global list an parse its parameters.

This also gives us a logical place to put duplicate module detection
in the next patch.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 36 insertions, 11 deletions

diff --git a/kernel/module.c b/kernel/module.c
index bbb1d812c79c..c690d9885797 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -560,7 +560,6 @@ static int already_uses(struct module *a, struct module *b)
  */
 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);
@@ -574,7 +573,6 @@ static int add_module_usage(struct module *a, struct module *b)
         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;
 }
 
@@ -619,7 +617,6 @@ static void module_unload_free(struct module *mod)
                 list_del(&use->source_list);
                 list_del(&use->target_list);
                 kfree(use);
-                sysfs_remove_link(i->holders_dir, mod->name);
         }
 }
 
@@ -1303,6 +1300,29 @@ static inline void remove_notes_attrs(struct module *mod)
 #endif
 
 #ifdef CONFIG_SYSFS
+static void add_usage_links(struct module *mod)
+{
+#ifdef CONFIG_MODULE_UNLOAD
+        struct module_use *use;
+        int nowarn;
+
+        list_for_each_entry(use, &mod->target_list, target_list) {
+                nowarn = sysfs_create_link(use->target->holders_dir,
+                                           &mod->mkobj.kobj, mod->name);
+        }
+#endif
+}
+
+static void del_usage_links(struct module *mod)
+{
+#ifdef CONFIG_MODULE_UNLOAD
+        struct module_use *use;
+
+        list_for_each_entry(use, &mod->target_list, target_list)
+                sysfs_remove_link(use->target->holders_dir, mod->name);
+#endif
+}
+
 int module_add_modinfo_attrs(struct module *mod)
 {
         struct module_attribute *attr;
@@ -1385,6 +1405,10 @@ int mod_sysfs_setup(struct module *mod,
 {
         int err;
 
+        err = mod_sysfs_init(mod);
+        if (err)
+                goto out;
+
         mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
         if (!mod->holders_dir) {
                 err = -ENOMEM;
@@ -1399,6 +1423,8 @@ int mod_sysfs_setup(struct module *mod,
         if (err)
                 goto out_unreg_param;
 
+        add_usage_links(mod);
+
         kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
         return 0;
 
@@ -1408,6 +1434,7 @@ out_unreg_holders:
         kobject_put(mod->holders_dir);
 out_unreg:
         kobject_put(&mod->mkobj.kobj);
+out:
         return err;
 }
 
@@ -1422,10 +1449,15 @@ static void mod_sysfs_fini(struct module *mod)
 {
 }
 
+static void del_usage_links(struct module *mod)
+{
+}
+
 #endif /* CONFIG_SYSFS */
 
 static void mod_kobject_remove(struct module *mod)
 {
+        del_usage_links(mod);
         module_remove_modinfo_attrs(mod);
         module_param_sysfs_remove(mod);
         kobject_put(mod->mkobj.drivers_dir);
@@ -2242,11 +2274,6 @@ static noinline struct module *load_module(void __user *umod,
         /* Now we've moved module, initialize linked lists, etc. */
         module_unload_init(mod);
 
-        /* add kobject, so we can reference it. */
-        err = mod_sysfs_init(mod);
-        if (err)
-                goto free_unload;
-
         /* Set up license info based on the info section */
         set_license(mod, get_modinfo(sechdrs, infoindex, "license"));
 
@@ -2443,6 +2470,7 @@ static noinline struct module *load_module(void __user *umod,
         err = mod_sysfs_setup(mod, mod->kp, mod->num_kp);
         if (err < 0)
                 goto unlink;
+
         add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
         add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
 
@@ -2461,9 +2489,6 @@ static noinline struct module *load_module(void __user *umod,
         module_arch_cleanup(mod);
  cleanup:
         free_modinfo(mod);
-        kobject_del(&mod->mkobj.kobj);
-        kobject_put(&mod->mkobj.kobj);
- free_unload:
         module_unload_free(mod);
 #if defined(CONFIG_MODULE_UNLOAD)
         free_percpu(mod->refptr);