[PATCH v6] kernel: param: initialize module_kset in a pure_initcall

[Shashank Balaji]

Commit "driver core: platform: set mod_name in driver registration" will set
struct device_driver's mod_name member for platform driver registration. For a
driver to be registered with its mod_name set, module_kset needs to be
initialized, which currently happens in a subsys_initcall in param_sysfs_init().
The tegra cbb drivers register themselves before module_kset init, in a
core_initcall. This works currently because lookup_or_create_module_kobject(),
which dereferences module_kset via kset_find_obj(), is not called if mod_name
is not set, which is the case now.

So in preparation for the commit "driver core: platform: set mod_name in driver registration",
move module_kset init to pure_initcall level, ensuring it happens before tegra
cbb driver registration.

Suggested-by: Gary Guo <gary@xxxxxxxxxxx>
Reviewed-by: Gary Guo <gary@xxxxxxxxxxx>
Co-developed-by: Rahul Bukte <rahul.bukte@xxxxxxxx>
Signed-off-by: Rahul Bukte <rahul.bukte@xxxxxxxx>
Signed-off-by: Shashank Balaji <shashank.mahadasyam@xxxxxxxx>
---
I'm sending v6 of just this patch to add the comment suggested by Petr and pick
up Gary's Reviewed-by. The rest of the patches are the same as v5.

Danilo, I'm assuming this series goes through driver-core. Could you please pick
up this version of this patch and the v5 of the others?
---
 kernel/params.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/params.c b/kernel/params.c
index 74d620bc2521..a668863a4bb6 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -942,9 +942,9 @@ const struct kobj_type module_ktype = {
 /*
  * param_sysfs_init - create "module" kset
  *
- * This must be done before the initramfs is unpacked and
- * request_module() thus becomes possible, because otherwise the
- * module load would fail in mod_sysfs_init.
+ * This must be done before any driver registration so that when a driver comes
+ * from a built-in module, the driver core can add the module under /sys/module
+ * and create the associated driver symlinks.
  */
 static int __init param_sysfs_init(void)
 {
@@ -957,7 +957,7 @@ static int __init param_sysfs_init(void)
 
 	return 0;
 }
-subsys_initcall(param_sysfs_init);
+pure_initcall(param_sysfs_init);
 
 /*
  * param_sysfs_builtin_init - add sysfs version and parameter
-- 
2.43.0