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, 85 insertions, 0 deletions

diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs
index a8fb4764185a..f989539a31b4 100644
--- a/rust/kernel/uaccess.rs
+++ b/rust/kernel/uaccess.rs
@@ -9,6 +9,7 @@ use crate::{
     bindings,
     error::Result,
     ffi::{c_char, c_void},
+    fs::file,
     prelude::*,
     transmute::{AsBytes, FromBytes},
 };
@@ -287,6 +288,48 @@ impl UserSliceReader {
         self.read_raw(out)
     }
 
+    /// Reads raw data from the user slice into a kernel buffer partially.
+    ///
+    /// This is the same as [`Self::read_slice`] but considers the given `offset` into `out` and
+    /// truncates the read to the boundaries of `self` and `out`.
+    ///
+    /// On success, returns the number of bytes read.
+    pub fn read_slice_partial(&mut self, out: &mut [u8], offset: usize) -> Result<usize> {
+        let end = offset.saturating_add(self.len()).min(out.len());
+
+        let Some(dst) = out.get_mut(offset..end) else {
+            return Ok(0);
+        };
+
+        self.read_slice(dst)?;
+        Ok(dst.len())
+    }
+
+    /// Reads raw data from the user slice into a kernel buffer partially.
+    ///
+    /// This is the same as [`Self::read_slice_partial`] but updates the given [`file::Offset`] by
+    /// the number of bytes read.
+    ///
+    /// This is equivalent to C's `simple_write_to_buffer()`.
+    ///
+    /// On success, returns the number of bytes read.
+    pub fn read_slice_file(&mut self, out: &mut [u8], offset: &mut file::Offset) -> Result<usize> {
+        if offset.is_negative() {
+            return Err(EINVAL);
+        }
+
+        let Ok(offset_index) = (*offset).try_into() else {
+            return Ok(0);
+        };
+
+        let read = self.read_slice_partial(out, offset_index)?;
+
+        // OVERFLOW: `offset + read <= data.len() <= isize::MAX <= Offset::MAX`
+        *offset += read as i64;
+
+        Ok(read)
+    }
+
     /// Reads a value of the specified type.
     ///
     /// Fails with [`EFAULT`] if the read happens on a bad address, or if the read goes out of
@@ -438,6 +481,48 @@ impl UserSliceWriter {
         Ok(())
     }
 
+    /// Writes raw data to this user pointer from a kernel buffer partially.
+    ///
+    /// This is the same as [`Self::write_slice`] but considers the given `offset` into `data` and
+    /// truncates the write to the boundaries of `self` and `data`.
+    ///
+    /// On success, returns the number of bytes written.
+    pub fn write_slice_partial(&mut self, data: &[u8], offset: usize) -> Result<usize> {
+        let end = offset.saturating_add(self.len()).min(data.len());
+
+        let Some(src) = data.get(offset..end) else {
+            return Ok(0);
+        };
+
+        self.write_slice(src)?;
+        Ok(src.len())
+    }
+
+    /// Writes raw data to this user pointer from a kernel buffer partially.
+    ///
+    /// This is the same as [`Self::write_slice_partial`] but updates the given [`file::Offset`] by
+    /// the number of bytes written.
+    ///
+    /// This is equivalent to C's `simple_read_from_buffer()`.
+    ///
+    /// On success, returns the number of bytes written.
+    pub fn write_slice_file(&mut self, data: &[u8], offset: &mut file::Offset) -> Result<usize> {
+        if offset.is_negative() {
+            return Err(EINVAL);
+        }
+
+        let Ok(offset_index) = (*offset).try_into() else {
+            return Ok(0);
+        };
+
+        let written = self.write_slice_partial(data, offset_index)?;
+
+        // OVERFLOW: `offset + written <= data.len() <= isize::MAX <= Offset::MAX`
+        *offset += written as i64;
+
+        Ok(written)
+    }
+
     /// Writes the provided Rust value to this userspace pointer.
     ///
     /// Fails with [`EFAULT`] if the write happens on a bad address, or if the write goes out of