Merge tag 'driver-core-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core

Pull driver core updates from Danilo Krummrich:
 "Arch Topology:
   - Move parse_acpi_topology() from arm64 to common code for reuse in
     RISC-V

  CPU:
   - Expose housekeeping CPUs through /sys/devices/system/cpu/housekeeping
   - Print a newline (or 0x0A) instead of '(null)' reading
     /sys/devices/system/cpu/nohz_full when nohz_full= is not set

  debugfs
   - Remove (broken) 'no-mount' mode
   - Remove redundant access mode checks in debugfs_get_tree() and
     debugfs_create_*() functions

  Devres:
   - Remove unused devm_free_percpu() helper
   - Move devm_alloc_percpu() from device.h to devres.h

  Firmware Loader:
   - Replace simple_strtol() with kstrtoint()
   - Do not call cancel_store() when no upload is in progress

  kernfs:
   - Increase struct super_block::maxbytes to MAX_LFS_FILESIZE
   - Fix a missing unwind path in __kernfs_new_node()

  Misc:
   - Increase the name size in struct auxiliary_device_id to 40
     characters
   - Replace system_unbound_wq with system_dfl_wq and add WQ_PERCPU to
     alloc_workqueue()

  Platform:
   - Replace ERR_PTR() with IOMEM_ERR_PTR() in platform ioremap
     functions

  Rust:
   - Auxiliary:
      - Unregister auxiliary device on parent device unbind
      - Move parent() to impl Device; implement device context aware
        parent() for Device<Bound>
      - Illustrate how to safely obtain a driver's device private data
        when calling from an auxiliary driver into the parant device
        driver

   - DebugFs:
      - Implement support for binary large objects

   - Device:
      - Let probe() return the driver's device private data as pinned
        initializer, i.e. impl PinInit<Self, Error>
      - Implement safe accessor for a driver's device private data for
        Device<Bound> (returned reference can't out-live driver binding
        and guarantees the correct private data type)
      - Implement AsBusDevice trait, to be used by class device
        abstractions to derive the bus device type of the parent device

   - DMA:
      - Store raw pointer of allocation as NonNull
      - Use start_ptr() and start_ptr_mut() to inherit correct
        mutability of self

   - FS:
      - Add file::Offset type alias

   - I2C:
      - Add abstractions for I2C device / driver infrastructure
      - Implement abstractions for manual I2C device registrations

   - I/O:
      - Use "kernel vertical" style for imports
      - Define ResourceSize as resource_size_t
      - Move ResourceSize to top-level I/O module
      - Add type alias for phys_addr_t
      - Implement Rust version of read_poll_timeout_atomic()

   - PCI:
      - Use "kernel vertical" style for imports
      - Move I/O and IRQ infrastructure to separate files
      - Add support for PCI interrupt vectors
      - Implement TryInto<IrqRequest<'a>> for IrqVector<'a> to convert
        an IrqVector bound to specific pci::Device into an IrqRequest
        bound to the same pci::Device's parent Device
      - Leverage pin_init_scope() to get rid of redundant Result in IRQ
        methods

   - PinInit:
      - Add {pin_}init_scope() to execute code before creating an
        initializer

   - Platform:
      - Leverage pin_init_scope() to get rid of redundant Result in IRQ
        methods

   - Timekeeping:
      - Implement abstraction of udelay()

   - Uaccess:
      - Implement read_slice_partial() and read_slice_file() for
        UserSliceReader
      - Implement write_slice_partial() and write_slice_file() for
        UserSliceWriter

  sysfs:
   - Prepare the constification of struct attribute"

* tag 'driver-core-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (75 commits)
  rust: pci: fix build failure when CONFIG_PCI_MSI is disabled
  debugfs: Fix default access mode config check
  debugfs: Remove broken no-mount mode
  debugfs: Remove redundant access mode checks
  driver core: Check drivers_autoprobe for all added devices
  driver core: WQ_PERCPU added to alloc_workqueue users
  driver core: replace use of system_unbound_wq with system_dfl_wq
  tick/nohz: Expose housekeeping CPUs in sysfs
  tick/nohz: avoid showing '(null)' if nohz_full= not set
  sysfs/cpu: Use DEVICE_ATTR_RO for nohz_full attribute
  kernfs: fix memory leak of kernfs_iattrs in __kernfs_new_node
  fs/kernfs: raise sb->maxbytes to MAX_LFS_FILESIZE
  mod_devicetable: Bump auxiliary_device_id name size
  sysfs: simplify attribute definition macros
  samples/kobject: constify 'struct foo_attribute'
  samples/kobject: add is_visible() callback to attribute group
  sysfs: attribute_group: enable const variants of is_visible()
  sysfs: introduce __SYSFS_FUNCTION_ALTERNATIVE()
  sysfs: transparently handle const pointers in ATTRIBUTE_GROUPS()
  sysfs: attribute_group: allow registration of const attribute
  ...

1 files changed, 75 insertions, 45 deletions

diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index 7a3b0b9c418e..56f3c180e8f6 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -7,6 +7,7 @@
 use crate::{
     bindings, container_of, device,
     device_id::{RawDeviceId, RawDeviceIdIndex},
+    devres::Devres,
     driver,
     error::{from_result, to_result, Result},
     prelude::*,
@@ -15,6 +16,7 @@ use crate::{
 };
 use core::{
     marker::PhantomData,
+    mem::offset_of,
     ptr::{addr_of_mut, NonNull},
 };
 
@@ -68,9 +70,9 @@ impl<T: Driver + 'static> Adapter<T> {
         let info = T::ID_TABLE.info(id.index());
 
         from_result(|| {
-            let data = T::probe(adev, info)?;
+            let data = T::probe(adev, info);
 
-            adev.as_ref().set_drvdata(data);
+            adev.as_ref().set_drvdata(data)?;
             Ok(0)
         })
     }
@@ -85,7 +87,7 @@ impl<T: Driver + 'static> Adapter<T> {
         // 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>>>() });
+        drop(unsafe { adev.as_ref().drvdata_obtain::<T>() });
     }
 }
 
@@ -184,7 +186,7 @@ pub trait Driver {
     /// 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>>>;
+    fn probe(dev: &Device<device::Core>, id_info: &Self::IdInfo) -> impl PinInit<Self, Error>;
 }
 
 /// The auxiliary device representation.
@@ -214,14 +216,25 @@ impl<Ctx: device::DeviceContext> Device<Ctx> {
         // `struct auxiliary_device`.
         unsafe { (*self.as_raw()).id }
     }
+}
+
+impl Device<device::Bound> {
+    /// Returns a bound reference to the parent [`device::Device`].
+    pub fn parent(&self) -> &device::Device<device::Bound> {
+        let parent = (**self).parent();
 
-    /// Returns a reference to the parent [`device::Device`], if any.
-    pub fn parent(&self) -> Option<&device::Device> {
-        self.as_ref().parent()
+        // SAFETY: A bound auxiliary device always has a bound parent device.
+        unsafe { parent.as_bound() }
     }
 }
 
 impl Device {
+    /// Returns a reference to the parent [`device::Device`].
+    pub fn parent(&self) -> &device::Device {
+        // SAFETY: A `struct auxiliary_device` always has a parent.
+        unsafe { self.as_ref().parent().unwrap_unchecked() }
+    }
+
     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`.
@@ -233,6 +246,12 @@ impl Device {
     }
 }
 
+// SAFETY: `auxiliary::Device` is a transparent wrapper of `struct auxiliary_device`.
+// The offset is guaranteed to point to a valid device field inside `auxiliary::Device`.
+unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx> {
+    const OFFSET: usize = offset_of!(bindings::auxiliary_device, dev);
+}
+
 // 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 });
@@ -278,8 +297,8 @@ 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.
+/// This type represents the registration of a [`struct auxiliary_device`]. When its parent device
+/// is unbound, the corresponding auxiliary device will be unregistered from the system.
 ///
 /// # Invariants
 ///
@@ -289,44 +308,55 @@ 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) };
+    pub fn new<'a>(
+        parent: &'a device::Device<device::Bound>,
+        name: &'a CStr,
+        id: u32,
+        modname: &'a CStr,
+    ) -> impl PinInit<Devres<Self>, Error> + 'a {
+        pin_init::pin_init_scope(move || {
+            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;
+            }
 
-        // 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 initialialized,
-        // - `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.
-            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) }))
+            // 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));
+            }
+
+            // INVARIANT: The device will remain registered until `auxiliary_device_delete()` is
+            // called, which happens in `Self::drop()`.
+            Ok(Devres::new(
+                parent,
+                // SAFETY: `adev` is guaranteed to be non-null, since the `KBox` was allocated
+                // successfully.
+                Self(unsafe { NonNull::new_unchecked(adev) }),
+            ))
+        })
     }
 }