[PATCH 0/2] efi: efivars: drop kobject from efivars_register()

[PATCH 0/2] efi: efivars: drop kobject from efivars_register()

[Johan Hovold]

Since the removal of the deprecated efivars sysfs interface there are
no users of the efivars kobject, which can be removed.

Included is also a related patch changing the return type of
efivar_supports_writes() to match the new efivar_is_available()
function.

Note that I intend to use efivar_is_available() in a driver with
optional EFI support (hence the dummy implementation) and the removal of
the kobject will simplify the upcoming Qualcomm UEFI Secure Application
driver somewhat too.

Johan


Johan Hovold (2):
  efi: efivars: drop kobject from efivars_register()
  efi: efivars: make efivar_supports_writes() return bool

 drivers/firmware/efi/efi.c     |  2 +-
 drivers/firmware/efi/vars.c    | 21 +++++++--------------
 drivers/firmware/google/gsmi.c |  2 +-
 fs/efivarfs/super.c            |  2 +-
 include/linux/efi.h            | 13 ++++++++-----
 5 files changed, 18 insertions(+), 22 deletions(-)

-- 
2.38.2

[PATCH 1/2] efi: efivars: drop kobject from efivars_register()

[Johan Hovold]

Since commit 0f5b2c69a4cb ("efi: vars: Remove deprecated 'efivars' sysfs
interface") and the removal of the sysfs interface there are no users of
the efivars kobject.

Drop the kobject argument from efivars_register() and add a new
efivar_is_available() helper in favour of the old efivars_kobject().

Note that the new helper uses the prefix 'efivar' (i.e. without an 's')
for consistency with efivar_supports_writes() and the rest of the
interface (except the registration functions).

For the benefit of drivers with optional EFI support, also provide a
dummy implementation of efivar_is_available().

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/firmware/efi/efi.c     |  2 +-
 drivers/firmware/efi/vars.c    | 19 ++++++-------------
 drivers/firmware/google/gsmi.c |  2 +-
 fs/efivarfs/super.c            |  2 +-
 include/linux/efi.h            | 11 +++++++----
 5 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 5aa8cd510bc0..a7f1a32537f1 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -197,7 +197,7 @@ static int generic_ops_register(void)
 		generic_ops.set_variable = efi.set_variable;
 		generic_ops.set_variable_nonblocking = efi.set_variable_nonblocking;
 	}
-	return efivars_register(&generic_efivars, &generic_ops, efi_kobj);
+	return efivars_register(&generic_efivars, &generic_ops);
 }
 
 static void generic_ops_unregister(void)
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 0ba9f18312f5..d6b2c4f9a575 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -40,37 +40,30 @@ static efi_status_t check_var_size(bool nonblocking, u32 attributes,
 }
 
 /**
- * efivars_kobject - get the kobject for the registered efivars
+ * efivar_is_available - check if efivars is available
  *
- * If efivars_register() has not been called we return NULL,
- * otherwise return the kobject used at registration time.
+ * @return true iff evivars is currently registered
  */
-struct kobject *efivars_kobject(void)
+bool efivar_is_available(void)
 {
-	if (!__efivars)
-		return NULL;
-
-	return __efivars->kobject;
+	return __efivars != NULL;
 }
-EXPORT_SYMBOL_GPL(efivars_kobject);
+EXPORT_SYMBOL_GPL(efivar_is_available);
 
 /**
  * efivars_register - register an efivars
  * @efivars: efivars to register
  * @ops: efivars operations
- * @kobject: @efivars-specific kobject
  *
  * Only a single efivars can be registered at any time.
  */
 int efivars_register(struct efivars *efivars,
-		     const struct efivar_operations *ops,
-		     struct kobject *kobject)
+		     const struct efivar_operations *ops)
 {
 	if (down_interruptible(&efivars_lock))
 		return -EINTR;
 
 	efivars->ops = ops;
-	efivars->kobject = kobject;
 
 	__efivars = efivars;
 
diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
index 4e2575dfeb90..60054a5d5de7 100644
--- a/drivers/firmware/google/gsmi.c
+++ b/drivers/firmware/google/gsmi.c
@@ -1029,7 +1029,7 @@ static __init int gsmi_init(void)
 	}
 
 #ifdef CONFIG_EFI
-	ret = efivars_register(&efivars, &efivar_ops, gsmi_kobj);
+	ret = efivars_register(&efivars, &efivar_ops);
 	if (ret) {
 		printk(KERN_INFO "gsmi: Failed to register efivars\n");
 		sysfs_remove_files(gsmi_kobj, gsmi_attrs);
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 07e82e246666..f72c529c8ec3 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -256,7 +256,7 @@ static struct file_system_type efivarfs_type = {
 
 static __init int efivarfs_init(void)
 {
-	if (!efivars_kobject())
+	if (!efivar_is_available())
 		return -ENODEV;
 
 	return register_filesystem(&efivarfs_type);
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 4b27519143f5..2124e55c02d6 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1039,7 +1039,6 @@ struct efivar_operations {
 
 struct efivars {
 	struct kset *kset;
-	struct kobject *kobject;
 	const struct efivar_operations *ops;
 };
 
@@ -1053,10 +1052,14 @@ struct efivars {
 #define EFI_VAR_NAME_LEN	1024
 
 int efivars_register(struct efivars *efivars,
-		     const struct efivar_operations *ops,
-		     struct kobject *kobject);
+		     const struct efivar_operations *ops);
 int efivars_unregister(struct efivars *efivars);
-struct kobject *efivars_kobject(void);
+
+#ifdef CONFIG_EFI
+bool efivar_is_available(void);
+#else
+static inline bool efivar_is_available(void) { return false; }
+#endif
 
 int efivar_supports_writes(void);
 
-- 
2.38.2

[PATCH 2/2] efi: efivars: make efivar_supports_writes() return bool

[Johan Hovold]

For consistency with the new efivar_is_available() function, change the
return type of efivar_supports_writes() to bool.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/firmware/efi/vars.c | 2 +-
 include/linux/efi.h         | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index d6b2c4f9a575..aa5ba38f81ff 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -110,7 +110,7 @@ int efivars_unregister(struct efivars *efivars)
 }
 EXPORT_SYMBOL_GPL(efivars_unregister);
 
-int efivar_supports_writes(void)
+bool efivar_supports_writes(void)
 {
 	return __efivars && __efivars->ops->set_variable;
 }
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 2124e55c02d6..f6b107da1cbc 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1061,7 +1061,7 @@ bool efivar_is_available(void);
 static inline bool efivar_is_available(void) { return false; }
 #endif
 
-int efivar_supports_writes(void);
+bool efivar_supports_writes(void);
 
 int efivar_lock(void);
 int efivar_trylock(void);
-- 
2.38.2

Re: [PATCH 0/2] efi: efivars: drop kobject from efivars_register()

[Ard Biesheuvel]

On Tue, 17 Jan 2023 at 13:46, Johan Hovold <johan+linaro@kernel.org> wrote:
>
> Since the removal of the deprecated efivars sysfs interface there are
> no users of the efivars kobject, which can be removed.
>
> Included is also a related patch changing the return type of
> efivar_supports_writes() to match the new efivar_is_available()
> function.
>
> Note that I intend to use efivar_is_available() in a driver with
> optional EFI support (hence the dummy implementation) and the removal of
> the kobject will simplify the upcoming Qualcomm UEFI Secure Application
> driver somewhat too.
>
> Johan
>
>
> Johan Hovold (2):
>   efi: efivars: drop kobject from efivars_register()
>   efi: efivars: make efivar_supports_writes() return bool
>

Thanks, I've queued these up now


>  drivers/firmware/efi/efi.c     |  2 +-
>  drivers/firmware/efi/vars.c    | 21 +++++++--------------
>  drivers/firmware/google/gsmi.c |  2 +-
>  fs/efivarfs/super.c            |  2 +-
>  include/linux/efi.h            | 13 ++++++++-----
>  5 files changed, 18 insertions(+), 22 deletions(-)
>
> --
> 2.38.2
>