[PATCH] efi/efivars: Create efivars mount point in the registration of efivars abstraction

[Lee, Chun-Yi]

This patch moved the logic of creating efivars mount point to the registration
of efivars abstraction. It is useful for userland to determine the availability
of efivars filesystem by checking the existence of mount point.

Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
---
 drivers/firmware/efi/efi.c  |  7 -------
 drivers/firmware/efi/vars.c | 17 +++++++++++++++++
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 3aa07c3b5136..23c11a2a3f4d 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -405,13 +405,6 @@ static int __init efisubsys_init(void)
 	if (error)
 		goto err_remove_group;
 
-	/* and the standard mountpoint for efivarfs */
-	error = sysfs_create_mount_point(efi_kobj, "efivars");
-	if (error) {
-		pr_err("efivars: Subsystem registration failed.\n");
-		goto err_remove_group;
-	}
-
 	if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS))
 		efi_debugfs_init();
 
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 973eef234b36..6fa7f288d635 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -1179,6 +1179,8 @@ int efivars_register(struct efivars *efivars,
 		     const struct efivar_operations *ops,
 		     struct kobject *kobject)
 {
+	int error;
+
 	if (down_interruptible(&efivars_lock))
 		return -EINTR;
 
@@ -1191,6 +1193,19 @@ int efivars_register(struct efivars *efivars,
 
 	up(&efivars_lock);
 
+	/* and the standard mountpoint for efivarfs */
+	if (efi_kobj) {
+		error = sysfs_create_mount_point(efi_kobj, "efivars");
+		if (error) {
+			if (down_interruptible(&efivars_lock))
+				return -EINTR;
+			__efivars = NULL;
+			up(&efivars_lock);
+			pr_err("efivars: Subsystem registration failed.\n");
+			return error;
+		}
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(efivars_register);
@@ -1222,6 +1237,8 @@ int efivars_unregister(struct efivars *efivars)
 
 	pr_info("Unregistered efivars operations\n");
 	__efivars = NULL;
+	if (efi_kobj)
+		sysfs_remove_mount_point(efi_kobj, "efivars");
 
 	rv = 0;
 out:
-- 
2.16.4

Thanks a lot!
Joey Lee

> On the other hand, the efisubsys_init() does not unregister efivars.0
> platform device in err_unregister block. It causes that efivars and
> efi-pstore be loaded when no generic_ops.
> 
> Let me know if I miss understood any thing, please.
> 
> 
> > 
> > 
> > > ---
> > >
> > > v2:
> > > Using efivars_kobject() helper instead of checking GetVariable or
> > > GetNextVariable EFI runtime services. Because the efivarfs code could be
> > > instantiated using a different efivars abstraction.
> > >
> > >  drivers/firmware/efi/efi.c | 12 +++++++-----
> > >  1 file changed, 7 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> > > index 3aa07c3b5136..db483fc68501 100644
> > > --- a/drivers/firmware/efi/efi.c
> > > +++ b/drivers/firmware/efi/efi.c
> > > @@ -405,11 +405,13 @@ static int __init efisubsys_init(void)
> > >         if (error)
> > >                 goto err_remove_group;
> > >
> > > -       /* and the standard mountpoint for efivarfs */
> > > -       error = sysfs_create_mount_point(efi_kobj, "efivars");
> > > -       if (error) {
> > > -               pr_err("efivars: Subsystem registration failed.\n");
> > > -               goto err_remove_group;
> > > +       if (efivars_kobject()) {
> > > +               /* and the standard mountpoint for efivarfs */
> > > +               error = sysfs_create_mount_point(efi_kobj, "efivars");
> > > +               if (error) {
> > > +                       pr_err("efivars: Subsystem registration failed.\n");
> > > +                       goto err_remove_group;
> > > +               }
> > >         }
> > >
> > >         if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS))
> > > --
> > > 2.16.4
> > >