module: add /sys/module/<name>/uevent files

Userspace wants to manage module parameters with udev rules.
This currently only works for loaded modules, but not for
built-in ones.

To allow access to the built-in modules we need to
re-trigger all module load events that happened before any
userspace was running. We already do the same thing for all
devices, subsystems(buses) and drivers.

This adds the currently missing /sys/module/<name>/uevent files
to all module entries.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (split & trivial fix)

2 files changed, 21 insertions, 0 deletions

diff --git a/kernel/module.c b/kernel/module.c
index a4295e67dd83..04379f92f843 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -975,10 +975,27 @@ static struct module_attribute initstate = {
         .show = show_initstate,
 };
 
+static ssize_t store_uevent(struct module_attribute *mattr,
+                            struct module_kobject *mk,
+                            const char *buffer, size_t count)
+{
+        enum kobject_action action;
+
+        if (kobject_action_type(buffer, count, &action) == 0)
+                kobject_uevent(&mk->kobj, action);
+        return count;
+}
+
+struct module_attribute module_uevent = {
+        .attr = { .name = "uevent", .mode = 0200 },
+        .store = store_uevent,
+};
+
 static struct module_attribute *modinfo_attrs[] = {
         &modinfo_version,
         &modinfo_srcversion,
         &initstate,
+        &module_uevent,
 #ifdef CONFIG_MODULE_UNLOAD
         &refcnt,
 #endif
diff --git a/kernel/params.c b/kernel/params.c
index 37e9b20a718b..22df3e0d142a 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -730,6 +730,10 @@ static struct module_kobject * __init locate_module_kobject(const char *name)
                 mk->kobj.kset = module_kset;
                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
                                            "%s", name);
+#ifdef CONFIG_MODULES
+                if (!err)
+                        err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
+#endif
                 if (err) {
                         kobject_put(&mk->kobj);
                         printk(KERN_ERR