[PATCH RFC 6/6] rust: WIP: Replace ModuleMetadata with THIS_MODULE

[Kari Argillander <kari.argillander@gmail.com>]

ModuleMetadata seems redudant after we have prober THIS_MODULE.
---
 drivers/gpu/nova-core/nova_core.rs    |  2 +-
 rust/kernel/auxiliary.rs              | 10 +++++++---
 rust/kernel/driver.rs                 | 10 ++++------
 rust/kernel/firmware.rs               |  2 +-
 rust/kernel/i2c.rs                    |  4 ++--
 rust/kernel/lib.rs                    |  8 ++------
 rust/kernel/pci.rs                    |  6 +++---
 rust/kernel/platform.rs               |  4 ++--
 rust/kernel/usb.rs                    |  6 +++---
 rust/macros/module.rs                 | 13 +++++++------
 samples/rust/rust_driver_auxiliary.rs |  6 +++---
 11 files changed, 35 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index b98a1c03f13d..fbfbcc9446c0 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -19,7 +19,7 @@
 mod util;
 mod vbios;
 
-pub(crate) const MODULE_NAME: &kernel::str::CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
+pub(crate) const MODULE_NAME: &kernel::str::CStr = THIS_MODULE::name();
 
 kernel::module_pci_driver! {
     type: driver::NovaCore,
diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index 323074322505..bd064b677c05 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -27,10 +27,10 @@
 unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
     type RegType = bindings::auxiliary_driver;
 
-    unsafe fn register<M: ThisModule>(adrv: &Opaque<Self::RegType>, name: &'static CStr) -> Result {
+    unsafe fn register<M: ThisModule>(adrv: &Opaque<Self::RegType>) -> Result {
         // SAFETY: It's safe to set the fields of `struct auxiliary_driver` on initialization.
         unsafe {
-            (*adrv.get()).name = name.as_char_ptr();
+            (*adrv.get()).name = M::NAME.as_char_ptr();
             (*adrv.get()).probe = Some(Self::probe_callback);
             (*adrv.get()).remove = Some(Self::remove_callback);
             (*adrv.get()).id_table = T::ID_TABLE.as_ptr();
@@ -38,7 +38,11 @@ unsafe fn register<M: ThisModule>(adrv: &Opaque<Self::RegType>, name: &'static C
 
         // SAFETY: `adrv` is guaranteed to be a valid `RegType`.
         to_result(unsafe {
-            bindings::__auxiliary_driver_register(adrv.get(), M::OWNER.as_ptr(), name.as_char_ptr())
+            bindings::__auxiliary_driver_register(
+                adrv.get(),
+                M::OWNER.as_ptr(),
+                M::NAME.as_char_ptr(),
+            )
         })
     }
 
diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs
index 7c4ad24bb48a..5bb029075a57 100644
--- a/rust/kernel/driver.rs
+++ b/rust/kernel/driver.rs
@@ -118,7 +118,7 @@ pub unsafe trait RegistrationOps {
     ///
     /// On success, `reg` must remain pinned and valid until the matching call to
     /// [`RegistrationOps::unregister`].
-    unsafe fn register<M: ThisModule>(reg: &Opaque<Self::RegType>, name: &'static CStr) -> Result;
+    unsafe fn register<M: ThisModule>(reg: &Opaque<Self::RegType>) -> Result;
 
     /// Unregisters a driver previously registered with [`RegistrationOps::register`].
     ///
@@ -151,7 +151,7 @@ unsafe impl<T: RegistrationOps> Send for Registration<T> {}
 
 impl<T: RegistrationOps> Registration<T> {
     /// Creates a new instance of the registration object.
-    pub fn new<M: ThisModule>(name: &'static CStr) -> impl PinInit<Self, Error> {
+    pub fn new<M: ThisModule>() -> impl PinInit<Self, Error> {
         try_pin_init!(Self {
             reg <- Opaque::try_ffi_init(|ptr: *mut T::RegType| {
                 // SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write.
@@ -162,7 +162,7 @@ pub fn new<M: ThisModule>(name: &'static CStr) -> impl PinInit<Self, Error> {
                 let drv = unsafe { &*(ptr as *const Opaque<T::RegType>) };
 
                 // SAFETY: `drv` is guaranteed to be pinned until `T::unregister`.
-                unsafe { T::register::<M>(drv, name) }
+                unsafe { T::register::<M>(drv) }
             }),
         })
     }
@@ -195,9 +195,7 @@ struct DriverModule {
         impl $crate::InPlaceModule for DriverModule {
             fn init<M: ::kernel::ThisModule>() -> impl ::pin_init::PinInit<Self, $crate::error::Error> {
                 $crate::try_pin_init!(Self {
-                    _driver <- $crate::driver::Registration::new::<M>(
-                        <Self as $crate::ModuleMetadata>::NAME,
-                    ),
+                    _driver <- $crate::driver::Registration::new::<M>(),
                 })
             }
         }
diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs
index 71168d8004e2..254b5c6b64af 100644
--- a/rust/kernel/firmware.rs
+++ b/rust/kernel/firmware.rs
@@ -206,7 +206,7 @@ macro_rules! module_firmware {
             const __MODULE_FIRMWARE_PREFIX: &'static $crate::str::CStr = if cfg!(MODULE) {
                 c""
             } else {
-                <LocalModule as $crate::ModuleMetadata>::NAME
+                THIS_MODULE::name()
             };
 
             #[link_section = ".modinfo"]
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index bc154506b16f..31db4d45bab1 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs
@@ -97,7 +97,7 @@ macro_rules! i2c_device_table {
 unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
     type RegType = bindings::i2c_driver;
 
-    unsafe fn register<M: ThisModule>(idrv: &Opaque<Self::RegType>, name: &'static CStr) -> Result {
+    unsafe fn register<M: ThisModule>(idrv: &Opaque<Self::RegType>) -> Result {
         build_assert!(
             T::ACPI_ID_TABLE.is_some() || T::OF_ID_TABLE.is_some() || T::I2C_ID_TABLE.is_some(),
             "At least one of ACPI/OF/Legacy tables must be present when registering an i2c driver"
@@ -120,7 +120,7 @@ unsafe fn register<M: ThisModule>(idrv: &Opaque<Self::RegType>, name: &'static C
 
         // SAFETY: It's safe to set the fields of `struct i2c_client` on initialization.
         unsafe {
-            (*idrv.get()).driver.name = name.as_char_ptr();
+            (*idrv.get()).driver.name = M::NAME.as_char_ptr();
             (*idrv.get()).probe = Some(Self::probe_callback);
             (*idrv.get()).remove = Some(Self::remove_callback);
             (*idrv.get()).shutdown = Some(Self::shutdown_callback);
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 6d4563662a02..3bae80a949d2 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -199,12 +199,6 @@ fn init<M: ThisModule>() -> impl pin_init::PinInit<Self, error::Error> {
     }
 }
 
-/// Metadata attached to a [`Module`] or [`InPlaceModule`].
-pub trait ModuleMetadata {
-    /// The name of the module as specified in the `module!` macro.
-    const NAME: &'static crate::str::CStr;
-}
-
 pub mod this_module {
     //! TODO
     //!
@@ -224,6 +218,8 @@ pub mod this_module {
     pub trait ThisModule {
         /// TODO Doc
         const OWNER: ModuleWrapper;
+        /// TODO Doc
+        const NAME: &'static kernel::str::CStr;
     }
 
     /// See [`this_module`]
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 792560ca8020..b043d7a388d0 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -54,10 +54,10 @@
 unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
     type RegType = bindings::pci_driver;
 
-    unsafe fn register<M: ThisModule>(pdrv: &Opaque<Self::RegType>, name: &'static CStr) -> Result {
+    unsafe fn register<M: ThisModule>(pdrv: &Opaque<Self::RegType>) -> Result {
         // SAFETY: It's safe to set the fields of `struct pci_driver` on initialization.
         unsafe {
-            (*pdrv.get()).name = name.as_char_ptr();
+            (*pdrv.get()).name = M::NAME.as_char_ptr();
             (*pdrv.get()).probe = Some(Self::probe_callback);
             (*pdrv.get()).remove = Some(Self::remove_callback);
             (*pdrv.get()).id_table = T::ID_TABLE.as_ptr();
@@ -65,7 +65,7 @@ unsafe fn register<M: ThisModule>(pdrv: &Opaque<Self::RegType>, name: &'static C
 
         // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
         to_result(unsafe {
-            bindings::__pci_register_driver(pdrv.get(), M::OWNER.as_ptr(), name.as_char_ptr())
+            bindings::__pci_register_driver(pdrv.get(), M::OWNER.as_ptr(), M::NAME.as_char_ptr())
         })
     }
 
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 67d46231600e..27f196a140e5 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -30,7 +30,7 @@
 unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
     type RegType = bindings::platform_driver;
 
-    unsafe fn register<M: ThisModule>(pdrv: &Opaque<Self::RegType>, name: &'static CStr) -> Result {
+    unsafe fn register<M: ThisModule>(pdrv: &Opaque<Self::RegType>) -> Result {
         let of_table = match T::OF_ID_TABLE {
             Some(table) => table.as_ptr(),
             None => core::ptr::null(),
@@ -43,7 +43,7 @@ unsafe fn register<M: ThisModule>(pdrv: &Opaque<Self::RegType>, name: &'static C
 
         // SAFETY: It's safe to set the fields of `struct platform_driver` on initialization.
         unsafe {
-            (*pdrv.get()).driver.name = name.as_char_ptr();
+            (*pdrv.get()).driver.name = M::NAME.as_char_ptr();
             (*pdrv.get()).probe = Some(Self::probe_callback);
             (*pdrv.get()).remove = Some(Self::remove_callback);
             (*pdrv.get()).driver.of_match_table = of_table;
diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index c6ee98d12875..43259307986f 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -31,10 +31,10 @@
 unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
     type RegType = bindings::usb_driver;
 
-    unsafe fn register<M: ThisModule>(udrv: &Opaque<Self::RegType>, name: &'static CStr) -> Result {
+    unsafe fn register<M: ThisModule>(udrv: &Opaque<Self::RegType>) -> Result {
         // SAFETY: It's safe to set the fields of `struct usb_driver` on initialization.
         unsafe {
-            (*udrv.get()).name = name.as_char_ptr();
+            (*udrv.get()).name = M::NAME.as_char_ptr();
             (*udrv.get()).probe = Some(Self::probe_callback);
             (*udrv.get()).disconnect = Some(Self::disconnect_callback);
             (*udrv.get()).id_table = T::ID_TABLE.as_ptr();
@@ -42,7 +42,7 @@ unsafe fn register<M: ThisModule>(udrv: &Opaque<Self::RegType>, name: &'static C
 
         // SAFETY: `udrv` is guaranteed to be a valid `RegType`.
         to_result(unsafe {
-            bindings::usb_register_driver(udrv.get(), M::OWNER.as_ptr(), name.as_char_ptr())
+            bindings::usb_register_driver(udrv.get(), M::OWNER.as_ptr(), M::NAME.as_char_ptr())
         })
     }
 
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 6b8753d122cc..6a1ce6435e8f 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs
@@ -375,6 +375,13 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
             #[allow(non_camel_case_types)]
             pub struct THIS_MODULE;
 
+            impl THIS_MODULE {{
+                /// Returns the name of this module.
+                pub const fn name() -> &'static ::kernel::str::CStr {{
+                    c\"{name}\"
+                }}
+            }}
+
             impl ::kernel::prelude::ThisModule for THIS_MODULE {{
                 #[cfg(not(MODULE))] 
                 const OWNER: ::kernel::this_module::ModuleWrapper = unsafe {{
@@ -392,13 +399,7 @@ impl ::kernel::prelude::ThisModule for THIS_MODULE {{
                     
                     ::kernel::this_module::ModuleWrapper::from_ptr(__this_module.get())
                 }};
-            }}
-
-            /// The `LocalModule` type is the type of the module created by `module!`,
-            /// `module_pci_driver!`, `module_platform_driver!`, etc.
-            type LocalModule = {type_};
 
-            impl ::kernel::ModuleMetadata for {type_} {{
                 const NAME: &'static ::kernel::str::CStr = c\"{name}\";
             }}
 
diff --git a/samples/rust/rust_driver_auxiliary.rs b/samples/rust/rust_driver_auxiliary.rs
index e996dca19454..2f77b0873e81 100644
--- a/samples/rust/rust_driver_auxiliary.rs
+++ b/samples/rust/rust_driver_auxiliary.rs
@@ -18,7 +18,7 @@
 use core::any::TypeId;
 use pin_init::PinInit;
 
-const MODULE_NAME: &CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
+const MODULE_NAME: &CStr = THIS_MODULE::name();
 const AUXILIARY_NAME: &CStr = c_str!("auxiliary");
 
 struct AuxiliaryDriver;
@@ -113,8 +113,8 @@ struct SampleModule {
 impl InPlaceModule for SampleModule {
     fn init<M: ThisModule>() -> impl PinInit<Self, Error> {
         try_pin_init!(Self {
-            _pci_driver <- driver::Registration::new::<M>(MODULE_NAME),
-            _aux_driver <- driver::Registration::new::<M>(MODULE_NAME),
+            _pci_driver <- driver::Registration::new::<M>(),
+            _aux_driver <- driver::Registration::new::<M>(),
         })
     }
 }

-- 
2.43.0