[PATCH] rust: auxiliary: Fix 'initialialized' typo

[PATCH] rust: auxiliary: Fix 'initialialized' typo

[JaimeFine]

From: Jaime Fine <jaimefine6@gmail.com>

Suggested-by: onur-ozkan

Link: https://github.com/Rust-for-Linux/linux/issues/1187
Signed-off-by: Jaime Fine <jaimefine6@gmail.com>
---
 rust/kernel/auxiliary.rs | 357 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 357 insertions(+)
 create mode 100644 rust/kernel/auxiliary.rs

diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
new file mode 100644
index 0000000..3626072
--- /dev/null
+++ b/rust/kernel/auxiliary.rs
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Abstractions for the auxiliary bus.
+//!
+//! C header: [`include/linux/auxiliary_bus.h`](srctree/include/linux/auxiliary_bus.h)
+
+use crate::{
+    bindings, container_of, device,
+    device_id::{RawDeviceId, RawDeviceIdIndex},
+    driver,
+    error::{from_result, to_result, Result},
+    prelude::*,
+    types::Opaque,
+    ThisModule,
+};
+use core::{
+    marker::PhantomData,
+    ptr::{addr_of_mut, NonNull},
+};
+
+/// An adapter for the registration of auxiliary drivers.
+pub struct Adapter<T: Driver>(T);
+
+// SAFETY: A call to `unregister` for a given instance of `RegType` is guaranteed to be valid if
+// a preceding call to `register` has been successful.
+unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
+    type RegType = bindings::auxiliary_driver;
+
+    unsafe fn register(
+        adrv: &Opaque<Self::RegType>,
+        name: &'static CStr,
+        module: &'static ThisModule,
+    ) -> 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()).probe = Some(Self::probe_callback);
+            (*adrv.get()).remove = Some(Self::remove_callback);
+            (*adrv.get()).id_table = T::ID_TABLE.as_ptr();
+        }
+
+        // SAFETY: `adrv` is guaranteed to be a valid `RegType`.
+        to_result(unsafe {
+            bindings::__auxiliary_driver_register(adrv.get(), module.0, name.as_char_ptr())
+        })
+    }
+
+    unsafe fn unregister(adrv: &Opaque<Self::RegType>) {
+        // SAFETY: `adrv` is guaranteed to be a valid `RegType`.
+        unsafe { bindings::auxiliary_driver_unregister(adrv.get()) }
+    }
+}
+
+impl<T: Driver + 'static> Adapter<T> {
+    extern "C" fn probe_callback(
+        adev: *mut bindings::auxiliary_device,
+        id: *const bindings::auxiliary_device_id,
+    ) -> kernel::ffi::c_int {
+        // SAFETY: The auxiliary bus only ever calls the probe callback with a valid pointer to a
+        // `struct auxiliary_device`.
+        //
+        // INVARIANT: `adev` is valid for the duration of `probe_callback()`.
+        let adev = unsafe { &*adev.cast::<Device<device::CoreInternal>>() };
+
+        // SAFETY: `DeviceId` is a `#[repr(transparent)`] wrapper of `struct auxiliary_device_id`
+        // and does not add additional invariants, so it's safe to transmute.
+        let id = unsafe { &*id.cast::<DeviceId>() };
+        let info = T::ID_TABLE.info(id.index());
+
+        from_result(|| {
+            let data = T::probe(adev, info)?;
+
+            adev.as_ref().set_drvdata(data);
+            Ok(0)
+        })
+    }
+
+    extern "C" fn remove_callback(adev: *mut bindings::auxiliary_device) {
+        // SAFETY: The auxiliary bus only ever calls the probe callback with a valid pointer to a
+        // `struct auxiliary_device`.
+        //
+        // INVARIANT: `adev` is valid for the duration of `probe_callback()`.
+        let adev = unsafe { &*adev.cast::<Device<device::CoreInternal>>() };
+
+        // SAFETY: `remove_callback` is only ever called after a successful call to
+        // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
+        // and stored a `Pin<KBox<T>>`.
+        drop(unsafe { adev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() });
+    }
+}
+
+/// Declares a kernel module that exposes a single auxiliary driver.
+#[macro_export]
+macro_rules! module_auxiliary_driver {
+    ($($f:tt)*) => {
+        $crate::module_driver!(<T>, $crate::auxiliary::Adapter<T>, { $($f)* });
+    };
+}
+
+/// Abstraction for `bindings::auxiliary_device_id`.
+#[repr(transparent)]
+#[derive(Clone, Copy)]
+pub struct DeviceId(bindings::auxiliary_device_id);
+
+impl DeviceId {
+    /// Create a new [`DeviceId`] from name.
+    pub const fn new(modname: &'static CStr, name: &'static CStr) -> Self {
+        let name = name.as_bytes_with_nul();
+        let modname = modname.as_bytes_with_nul();
+
+        // TODO: Replace with `bindings::auxiliary_device_id::default()` once stabilized for
+        // `const`.
+        //
+        // SAFETY: FFI type is valid to be zero-initialized.
+        let mut id: bindings::auxiliary_device_id = unsafe { core::mem::zeroed() };
+
+        let mut i = 0;
+        while i < modname.len() {
+            id.name[i] = modname[i];
+            i += 1;
+        }
+
+        // Reuse the space of the NULL terminator.
+        id.name[i - 1] = b'.';
+
+        let mut j = 0;
+        while j < name.len() {
+            id.name[i] = name[j];
+            i += 1;
+            j += 1;
+        }
+
+        Self(id)
+    }
+}
+
+// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `auxiliary_device_id` and does not add
+// additional invariants, so it's safe to transmute to `RawType`.
+unsafe impl RawDeviceId for DeviceId {
+    type RawType = bindings::auxiliary_device_id;
+}
+
+// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field.
+unsafe impl RawDeviceIdIndex for DeviceId {
+    const DRIVER_DATA_OFFSET: usize =
+        core::mem::offset_of!(bindings::auxiliary_device_id, driver_data);
+
+    fn index(&self) -> usize {
+        self.0.driver_data
+    }
+}
+
+/// IdTable type for auxiliary drivers.
+pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
+
+/// Create a auxiliary `IdTable` with its alias for modpost.
+#[macro_export]
+macro_rules! auxiliary_device_table {
+    ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
+        const $table_name: $crate::device_id::IdArray<
+            $crate::auxiliary::DeviceId,
+            $id_info_type,
+            { $table_data.len() },
+        > = $crate::device_id::IdArray::new($table_data);
+
+        $crate::module_device_table!("auxiliary", $module_table_name, $table_name);
+    };
+}
+
+/// The auxiliary driver trait.
+///
+/// Drivers must implement this trait in order to get an auxiliary driver registered.
+pub trait Driver {
+    /// The type holding information about each device id supported by the driver.
+    ///
+    /// TODO: Use associated_type_defaults once stabilized:
+    ///
+    /// type IdInfo: 'static = ();
+    type IdInfo: 'static;
+
+    /// The table of device ids supported by the driver.
+    const ID_TABLE: IdTable<Self::IdInfo>;
+
+    /// Auxiliary driver probe.
+    ///
+    /// Called when an auxiliary device is matches a corresponding driver.
+    fn probe(dev: &Device<device::Core>, id_info: &Self::IdInfo) -> Result<Pin<KBox<Self>>>;
+}
+
+/// The auxiliary device representation.
+///
+/// This structure represents the Rust abstraction for a C `struct auxiliary_device`. The
+/// implementation abstracts the usage of an already existing C `struct auxiliary_device` within
+/// Rust code that we get passed from the C side.
+///
+/// # Invariants
+///
+/// A [`Device`] instance represents a valid `struct auxiliary_device` created by the C portion of
+/// the kernel.
+#[repr(transparent)]
+pub struct Device<Ctx: device::DeviceContext = device::Normal>(
+    Opaque<bindings::auxiliary_device>,
+    PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> Device<Ctx> {
+    fn as_raw(&self) -> *mut bindings::auxiliary_device {
+        self.0.get()
+    }
+
+    /// Returns the auxiliary device' id.
+    pub fn id(&self) -> u32 {
+        // SAFETY: By the type invariant `self.as_raw()` is a valid pointer to a
+        // `struct auxiliary_device`.
+        unsafe { (*self.as_raw()).id }
+    }
+
+    /// Returns a reference to the parent [`device::Device`], if any.
+    pub fn parent(&self) -> Option<&device::Device> {
+        let ptr: *const Self = self;
+        // CAST: `Device<Ctx: DeviceContext>` types are transparent to each other.
+        let ptr: *const Device = ptr.cast();
+        // SAFETY: `ptr` was derived from `&self`.
+        let this = unsafe { &*ptr };
+
+        this.as_ref().parent()
+    }
+}
+
+impl Device {
+    extern "C" fn release(dev: *mut bindings::device) {
+        // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device`
+        // embedded in `struct auxiliary_device`.
+        let adev = unsafe { container_of!(dev, bindings::auxiliary_device, dev) };
+
+        // SAFETY: `adev` points to the memory that has been allocated in `Registration::new`, via
+        // `KBox::new(Opaque::<bindings::auxiliary_device>::zeroed(), GFP_KERNEL)`.
+        let _ = unsafe { KBox::<Opaque<bindings::auxiliary_device>>::from_raw(adev.cast()) };
+    }
+}
+
+// SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic
+// argument.
+kernel::impl_device_context_deref!(unsafe { Device });
+kernel::impl_device_context_into_aref!(Device);
+
+// SAFETY: Instances of `Device` are always reference-counted.
+unsafe impl crate::types::AlwaysRefCounted for Device {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
+        unsafe { bindings::get_device(self.as_ref().as_raw()) };
+    }
+
+    unsafe fn dec_ref(obj: NonNull<Self>) {
+        // CAST: `Self` a transparent wrapper of `bindings::auxiliary_device`.
+        let adev: *mut bindings::auxiliary_device = obj.cast().as_ptr();
+
+        // SAFETY: By the type invariant of `Self`, `adev` is a pointer to a valid
+        // `struct auxiliary_device`.
+        let dev = unsafe { addr_of_mut!((*adev).dev) };
+
+        // SAFETY: The safety requirements guarantee that the refcount is non-zero.
+        unsafe { bindings::put_device(dev) }
+    }
+}
+
+impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
+    fn as_ref(&self) -> &device::Device<Ctx> {
+        // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
+        // `struct auxiliary_device`.
+        let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) };
+
+        // SAFETY: `dev` points to a valid `struct device`.
+        unsafe { device::Device::from_raw(dev) }
+    }
+}
+
+// SAFETY: A `Device` is always reference-counted and can be released from any thread.
+unsafe impl Send for Device {}
+
+// SAFETY: `Device` can be shared among threads because all methods of `Device`
+// (i.e. `Device<Normal>) are thread safe.
+unsafe impl Sync for Device {}
+
+/// The registration of an auxiliary device.
+///
+/// This type represents the registration of a [`struct auxiliary_device`]. When an instance of this
+/// type is dropped, its respective auxiliary device will be unregistered from the system.
+///
+/// # Invariants
+///
+/// `self.0` always holds a valid pointer to an initialized and registered
+/// [`struct auxiliary_device`].
+pub struct Registration(NonNull<bindings::auxiliary_device>);
+
+impl Registration {
+    /// Create and register a new auxiliary device.
+    pub fn new(parent: &device::Device, name: &CStr, id: u32, modname: &CStr) -> Result<Self> {
+        let boxed = KBox::new(Opaque::<bindings::auxiliary_device>::zeroed(), GFP_KERNEL)?;
+        let adev = boxed.get();
+
+        // SAFETY: It's safe to set the fields of `struct auxiliary_device` on initialization.
+        unsafe {
+            (*adev).dev.parent = parent.as_raw();
+            (*adev).dev.release = Some(Device::release);
+            (*adev).name = name.as_char_ptr();
+            (*adev).id = id;
+        }
+
+        // SAFETY: `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`,
+        // which has not been initialized yet.
+        unsafe { bindings::auxiliary_device_init(adev) };
+
+        // Now that `adev` is initialized, leak the `Box`; the corresponding memory will be freed
+        // by `Device::release` when the last reference to the `struct auxiliary_device` is dropped.
+        let _ = KBox::into_raw(boxed);
+
+        // SAFETY:
+        // - `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`, which has
+        //   been initialized,
+        // - `modname.as_char_ptr()` is a NULL terminated string.
+        let ret = unsafe { bindings::__auxiliary_device_add(adev, modname.as_char_ptr()) };
+        if ret != 0 {
+            // SAFETY: `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`,
+            // which has been initialized.
+            unsafe { bindings::auxiliary_device_uninit(adev) };
+
+            return Err(Error::from_errno(ret));
+        }
+
+        // SAFETY: `adev` is guaranteed to be non-null, since the `KBox` was allocated successfully.
+        //
+        // INVARIANT: The device will remain registered until `auxiliary_device_delete()` is called,
+        // which happens in `Self::drop()`.
+        Ok(Self(unsafe { NonNull::new_unchecked(adev) }))
+    }
+}
+
+impl Drop for Registration {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariant of `Self`, `self.0.as_ptr()` is a valid registered
+        // `struct auxiliary_device`.
+        unsafe { bindings::auxiliary_device_delete(self.0.as_ptr()) };
+
+        // This drops the reference we acquired through `auxiliary_device_init()`.
+        //
+        // SAFETY: By the type invariant of `Self`, `self.0.as_ptr()` is a valid registered
+        // `struct auxiliary_device`.
+        unsafe { bindings::auxiliary_device_uninit(self.0.as_ptr()) };
+    }
+}
+
+// SAFETY: A `Registration` of a `struct auxiliary_device` can be released from any thread.
+unsafe impl Send for Registration {}
+
+// SAFETY: `Registration` does not expose any methods or fields that need synchronization.
+unsafe impl Sync for Registration {}
-- 
2.50.0.windows.1

Re: [PATCH] rust: auxiliary: Fix 'initialialized' typo

[Greg KH]

On Mon, Sep 15, 2025 at 08:02:27PM +0800, JaimeFine wrote:
> From: Jaime Fine <jaimefine6@gmail.com>
> 
> Suggested-by: onur-ozkan

What specific "typo" is being changed here?

> Link: https://github.com/Rust-for-Linux/linux/issues/1187
> Signed-off-by: Jaime Fine <jaimefine6@gmail.com>
> ---
>  rust/kernel/auxiliary.rs | 357 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 357 insertions(+)
>  create mode 100644 rust/kernel/auxiliary.rs
> 
> diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
> new file mode 100644
> index 0000000..3626072
> --- /dev/null
> +++ b/rust/kernel/auxiliary.rs

You added a whole file, you did not modify an existing one :(

Also, please use scripts/get_maintainer.pl to determine who to send
patches to.

thanks,

greg k-h

[PATCH] rust: auxiliary: fix "initialialized" typo

[JaimeF]

From: Jaime Fan <jaimefine6@gmail.com>

Fixes a spelling mistake in a comment: "initialialized" → "initialized".
This improves clarity in the documentation and avoids confusion for readers.

Suggested-by: onur-ozkan <work@onurozkan.dev>
Link: https://github.com/Rust-for-Linux/linux/issues/1187
Signed-off-by: Jaime Fan <jaimefine6@gmail.com>
---
 rust/kernel/auxiliary.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index 58be09871397..129eae8ff2e7 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -317,12 +317,12 @@ pub fn new(parent: &device::Device, name: &CStr, id: u32, modname: &CStr) -> Res
 
         // SAFETY:
         // - `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`, which has
-        //   been initialialized,
+        //   been initialized,
         // - `modname.as_char_ptr()` is a NULL terminated string.
         let ret = unsafe { bindings::__auxiliary_device_add(adev, modname.as_char_ptr()) };
         if ret != 0 {
             // SAFETY: `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`,
-            // which has been initialialized.
+            // which has been initialized.
             unsafe { bindings::auxiliary_device_uninit(adev) };
 
             return Err(Error::from_errno(ret));
-- 
2.50.1

Re: [PATCH] rust: auxiliary: fix "initialialized" typo

[Greg KH]

On Tue, Sep 16, 2025 at 12:41:02PM +0000, JaimeF wrote:
> From: Jaime Fan <jaimefine6@gmail.com>
> 
> Fixes a spelling mistake in a comment: "initialialized" → "initialized".
> This improves clarity in the documentation and avoids confusion for readers.
> 
> Suggested-by: onur-ozkan <work@onurozkan.dev>
> Link: https://github.com/Rust-for-Linux/linux/issues/1187
> Signed-off-by: Jaime Fan <jaimefine6@gmail.com>
> ---
>  rust/kernel/auxiliary.rs | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
> index 58be09871397..129eae8ff2e7 100644
> --- a/rust/kernel/auxiliary.rs
> +++ b/rust/kernel/auxiliary.rs
> @@ -317,12 +317,12 @@ pub fn new(parent: &device::Device, name: &CStr, id: u32, modname: &CStr) -> Res
>  
>          // SAFETY:
>          // - `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`, which has
> -        //   been initialialized,
> +        //   been initialized,
>          // - `modname.as_char_ptr()` is a NULL terminated string.
>          let ret = unsafe { bindings::__auxiliary_device_add(adev, modname.as_char_ptr()) };
>          if ret != 0 {
>              // SAFETY: `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`,
> -            // which has been initialialized.
> +            // which has been initialized.
>              unsafe { bindings::auxiliary_device_uninit(adev) };
>  
>              return Err(Error::from_errno(ret));
> -- 
> 2.50.1
> 


Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- This looks like a new version of a previously submitted patch, but you
  did not list below the --- line any changes from the previous version.
  Please read the section entitled "The canonical patch format" in the
  kernel file, Documentation/process/submitting-patches.rst for what
  needs to be done here to properly describe this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

Re: [PATCH] rust: auxiliary: fix "initialialized" typo

[Greg KH]

On Tue, Sep 16, 2025 at 09:01:49PM +0800, Jaime Fine wrote:
> Fixed!

Please slow down and relax.  Take a day at the very least between patch
submissions to fully read the responses and then do a new version.
There is no rush here.

thanks,

greg k-h

Re: [PATCH] rust: auxiliary: fix "initialialized" typo

[Greg KH]

On Tue, Sep 16, 2025 at 12:41:02PM +0000, JaimeF wrote:
> From: Jaime Fan <jaimefine6@gmail.com>
> 
> Fixes a spelling mistake in a comment: "initialialized" → "initialized".
> This improves clarity in the documentation and avoids confusion for readers.
> 
> Suggested-by: onur-ozkan <work@onurozkan.dev>
> Link: https://github.com/Rust-for-Linux/linux/issues/1187
> Signed-off-by: Jaime Fan <jaimefine6@gmail.com>
> ---
>  rust/kernel/auxiliary.rs | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
> index 58be09871397..129eae8ff2e7 100644
> --- a/rust/kernel/auxiliary.rs
> +++ b/rust/kernel/auxiliary.rs
> @@ -317,12 +317,12 @@ pub fn new(parent: &device::Device, name: &CStr, id: u32, modname: &CStr) -> Res
>  
>          // SAFETY:
>          // - `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`, which has
> -        //   been initialialized,
> +        //   been initialized,
>          // - `modname.as_char_ptr()` is a NULL terminated string.
>          let ret = unsafe { bindings::__auxiliary_device_add(adev, modname.as_char_ptr()) };
>          if ret != 0 {
>              // SAFETY: `adev` is guaranteed to be a valid pointer to a `struct auxiliary_device`,
> -            // which has been initialialized.
> +            // which has been initialized.
>              unsafe { bindings::auxiliary_device_uninit(adev) };
>  
>              return Err(Error::from_errno(ret));
> -- 
> 2.50.1
> 
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- This looks like a new version of a previously submitted patch, but you
  did not list below the --- line any changes from the previous version.
  Please read the section entitled "The canonical patch format" in the
  kernel file, Documentation/process/submitting-patches.rst for what
  needs to be done here to properly describe this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

Re: [PATCH] rust: auxiliary: fix "initialialized" typo

[Ira Weiny]

Greg KH wrote:
> On Tue, Sep 16, 2025 at 09:01:49PM +0800, Jaime Fine wrote:
> > Fixed!
> 
> Please slow down and relax.  Take a day at the very least between patch
> submissions to fully read the responses and then do a new version.
> There is no rush here.

+1

And perhaps check out the b4 tool[*] which can help with tracking changes
to a patch set and help with patch submissions.

[*] https://git.kernel.org/pub/scm/utils/b4/b4.git

See the prep option.

Ira