commit e54ad0cd3673c93cdafda58505eaa81610fe3aef upstream.

Invariants should be prefixed with a # to turn it into a header.

There are no functional changes in this patch.

Cc: stable@vger.kernel.org
Fixes: c284d3e42338 ("rust: drm: gem: Add GEM object abstraction")
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patch.msgid.link/20251107202603.465932-1-lyude@redhat.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull drm updates from Dave Airlie:
 "cross-subsystem:
   - i2c-hid: Make elan touch controllers power on after panel is
     enabled
   - dt bindings for STM32MP25 SoC
   - pci vgaarb: use screen_info helpers
   - rust pin-init updates
   - add MEI driver for late binding firmware update/load

  uapi:
   - add ioctl for reassigning GEM handles
   - provide boot_display attribute on boot-up devices

  core:
   - document DRM_MODE_PAGE_FLIP_EVENT
   - add vendor specific recovery method to drm device wedged uevent

  gem:
   - Simplify gpuvm locking

  ttm:
   - add interface to populate buffers

  sched:
   - Fix race condition in trace code

  atomic:
   - Reallow no-op async page flips

  display:
   - dp: Fix command length

  video:
   - Improve pixel-format handling for struct screen_info

  rust:
   - drop Opaque<> from ioctl args
   - Alloc:
       - BorrowedPage type and AsPageIter traits
       - Implement Vmalloc::to_page() and VmallocPageIter
   - DMA/Scatterlist:
       - Add dma::DataDirection and type alias for dma_addr_t
       - Abstraction for struct scatterlist and sg_table
   - DRM:
       - simplify use of generics
       - add DriverFile type alias
       - drop Object::SIZE
   - Rust:
       - pin-init tree merge
       - Various methods for AsBytes and FromBytes traits

  gpuvm:
   - Support madvice in Xe driver

  gpusvm:
   - fix hmm_pfn_to_map_order usage in gpusvm

  bridge:
   - Improve and fix ref counting on bridge management
   - cdns-dsi: Various improvements to mode setting
   - Support Solomon SSD2825 plus DT bindings
   - Support Waveshare DSI2DPI plus DT bindings
   - Support Content Protection property
   - display-connector: Improve DP display detection
   - Add support for Radxa Ra620 plus DT bindings
   - adv7511: Provide SPD and HDMI infoframes
   - it6505: Replace crypto_shash with sha()
   - synopsys: Add support for DW DPTX Controller plus DT bindings
   - adv7511: Write full Audio infoframe
   - ite6263: Support vendor-specific infoframes
   - simple: Add support for Realtek RTD2171 DP-to-HDMI plus DT bindings

  panel:
   - panel-edp: Support mt8189 Chromebooks; Support BOE NV140WUM-N64;
     Support SHP LQ134Z1; Fixes
   - panel-simple: Support Olimex LCD-OLinuXino-5CTS plus DT bindings
   - Support Samsung AMS561RA01
   - Support Hydis HV101HD1 plus DT bindings
   - ilitek-ili9881c: Refactor mode setting; Add support for Bestar
     BSD1218-A101KL68 LCD plus DT bindings
   - lvds: Add support for Ampire AMP19201200B5TZQW-T03 to DT bindings
   - edp: Add support for additonal mt8189 Chromebook panels
   - lvds: Add DT bindings for EDT ETML0700Z8DHA

  amdgpu:
   - add CRIU support for gem objects
   - RAS updates
   - VCN SRAM load fixes
   - EDID read fixes
   - eDP ALPM support
   - Documentation updates
   - Rework PTE flag generation
   - DCE6 fixes
   - VCN devcoredump cleanup
   - MMHUB client id fixes
   - VCN 5.0.1 RAS support
   - SMU 13.0.x updates
   - Expanded PCIe DPC support
   - Expanded VCN reset support
   - VPE per queue reset support
   - give kernel jobs unique id for tracing
   - pre-populate exported buffers
   - cyan skillfish updates
   - make vbios build number available in sysfs
   - userq updates
   - HDCP updates
   - support MMIO remap page as ttm pool
   - JPEG parser updates
   - DCE6 DC updates
   - use devm for i2c buses
   - GPUVM locking updates
   - Drop non-DC DCE11 code
   - improve fallback handling for pixel encoding

  amdkfd:
   - SVM/page migration fixes
   - debugfs fixes
   - add CRIO support for gem objects
   - SVM updates

  radeon:
   - use dev_warn_once in CS parsers

  xe:
   - add madvise interface
   - add DRM_IOCTL_XE_VM_QUERY_MEMORY_RANGE_ATTRS to query VMA count
     and memory attributes
   - drop L# bank mask reporting from media GT3 on Xe3+.
   - add SLPC power_profile sysfs interface
   - add configs attribs to add post/mid context-switch commands
   - handle firmware reported hardware errors notifying userspace with
     device wedged uevent
   - use same dir structure across sysfs/debugfs
   - cleanup and future proof vram region init
   - add G-states and PCI link states to debugfs
   - Add SRIOV support for CCS surfaces on Xe2+
   - Enable SRIOV PF mode by default on supported platforms
   - move flush to common code
   - extended core workarounds for Xe2/3
   - use DRM scheduler for delayed GT TLB invalidations
   - configs improvements and allow VF device enablement
   - prep work to expose mmio regions to userspace
   - VF migration support added
   - prepare GPU SVM for THP migration
   - start fixing XE_PAGE_SIZE vs PAGE_SIZE
   - add PSMI support for hw validation
   - resize VF bars to max possible size according to number of VFs
   - Ensure GT is in C0 during resume
   - pre-populate exported buffers
   - replace xe_hmm with gpusvm
   - add more SVM GT stats to debugfs
   - improve fake pci and WA kunnit handle for new platform testing
   - Test GuC to GuC comms to add debugging
   - use attribute groups to simplify sysfs registration
   - add Late Binding firmware code to interact with MEI

  i915:
   - apply multiple JSL/EHL/Gen7/Gen6 workarounds properly
   - protect against overflow in active_engine()
   - Use try_cmpxchg64() in __active_lookup()
   - include GuC registers in error state
   - get rid of dev->struct_mutex
   - iopoll: generalize read_poll_timout
   - lots more display refactoring
   - Reject HBR3 in any eDP Panel
   - Prune modes for YUV420
   - Display Wa fix, additions, and updates
   - DP: Fix 2.7 Gbps link training on g4x
   - DP: Adjust the idle pattern handling
   - DP: Shuffle the link training code a bit
   - Don't set/read the DSI C clock divider on GLK
   - Enable_psr kernel parameter changes
   - Type-C enabled/disconnected dp-alt sink
   - Wildcat Lake enabling
   - DP HDR updates
   - DRAM detection
   - wait PSR idle on dsb commit
   - Remove FBC modulo 4 restriction for ADL-P+
   - panic: refactor framebuffer allocation

  habanalabs:
   - debug/visibility improvements
   - vmalloc-backed coherent mmap support
   - HLDIO infrastructure

  nova-core:
   - various register!() macro improvements
   - minor vbios/firmware fixes/refactoring
   - advance firmware boot stages; process Booter and patch signatures
   - process GSP and GSP bootloader
   - Add r570.144 firmware bindings and update to it
   - Move GSP boot code to own module
   - Use new pin-init features to store driver's private data in a
     single allocation
   - Update ARef import from sync::aref

  nova-drm:
   - Update ARef import from sync::aref

  tyr:
   - initial driver skeleton for a rust driver for ARM Mali GPUs
   - capable of powering up, query metadata and provide it to userspace.

  msm:
   - GPU and Core:
      - in DT bindings describe clocks per GPU type
      - GMU bandwidth voting for x1-85
      - a623/a663 speedbins
      - cleanup some remaining no-iommu leftovers after VM_BIND conversion
      - fix GEM obj 32b size truncation
      - add missing VM_BIND param validation
      - IFPC for x1-85 and a750
      - register xml and gen_header.py sync from mesa
   - Display:
      - add missing bindings for display on SC8180X
      - added DisplayPort MST bindings
      - conversion from round_rate() to determine_rate()

  amdxdna:
   - add IOCTL_AMDXDNA_GET_ARRAY
   - support user space allocated buffers
   - streamline PM interfaces
   - Refactoring wrt. hardware contexts
   - improve error reporting

  nouveau:
   - use GSP firmware by default
   - improve error reporting
   - Pre-populate exported buffers

  ast:
   - Clean up detection of DRAM config

  exynos:
   - add DSIM bridge driver support for Exynos7870
   - Document Exynos7870 DSIM compatible in dt-binding

  panthor:
   - Print task/pid on errors
   - Add support for Mali G710, G510, G310, Gx15, Gx20, Gx25
   - Improve cache flushing
   - Fail VM bind if BO has offset

  renesas:
   - convert to RUNTIME_PM_OPS

  rcar-du:
   - Make number of lanes configurable
   - Use RUNTIME_PM_OPS
   - Add support for DSI commands

  rocket:
   - Add driver for Rockchip NPU plus DT bindings
   - Use kfree() and sizeof() correctly
   - Test DMA status

  rockchip:
   - dsi2: Add support for RK3576 plus DT bindings
   - Add support for RK3588 DPTX output

  tidss:
   - Use crtc_ fields for programming display mode
   - Remove other drivers from aperture

  pixpaper:
   - Add support for Mayqueen Pixpaper plus DT bindings

  v3d:
   - Support querying nubmer of GPU resets for KHR_robustness

  stm:
   - Clean up logging
   - ltdc: Add support support for STM32MP257F-EV1 plus DT bindings

  sitronix:
   - st7571-i2c: Add support for inverted displays and 2-bit grayscale

  tidss:
   - Convert to kernel's FIELD_ macros

  vesadrm:
   - Support 8-bit palette mode

  imagination:
   - Improve power management
   - Add support for TH1520 GPU
   - Support Risc-V architectures

  v3d:
   - Improve job management and locking

  vkms:
   - Support variants of ARGB8888, ARGB16161616, RGB565, RGB888 and P01x
   - Spport YUV with 16-bit components"

* tag 'drm-next-2025-10-01' of https://gitlab.freedesktop.org/drm/kernel: (1455 commits)
  drm/amd: Add name to modes from amdgpu_connector_add_common_modes()
  drm/amd: Drop some common modes from amdgpu_connector_add_common_modes()
  drm/amdgpu: update MODULE_PARM_DESC for freesync_video
  drm/amd: Use dynamic array size declaration for amdgpu_connector_add_common_modes()
  drm/amd/display: Share dce100_validate_global with DCE6-8
  drm/amd/display: Share dce100_validate_bandwidth with DCE6-8
  drm/amdgpu: Fix fence signaling race condition in userqueue
  amd/amdkfd: enhance kfd process check in switch partition
  amd/amdkfd: resolve a race in amdgpu_amdkfd_device_fini_sw
  drm/amd/display: Reject modes with too high pixel clock on DCE6-10
  drm/amd: Drop unnecessary check in amdgpu_connector_add_common_modes()
  drm/amd/display: Only enable common modes for eDP and LVDS
  drm/amdgpu: remove the redeclaration of variable i
  drm/amdgpu/userq: assign an error code for invalid userq va
  drm/amdgpu: revert "rework reserved VMID handling" v2
  drm/amdgpu: remove leftover from enforcing isolation by VMID
  drm/amdgpu: Add fallback to pipe reset if KCQ ring reset fails
  accel/habanalabs: add Infineon version check
  accel/habanalabs/gaudi2: read preboot status after recovering from dirty state
  accel/habanalabs: add HL_GET_P_STATE passthrough type
  ...

We need the DRM Rust changes that went into drm-misc before the
existence of the drm-rust tree in here as well.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Drive-by fix, it doesn't seem like anything actually uses this constant
anymore.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250908185239.135849-4-lyude@redhat.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Just to reduce the clutter with the File<…> types in gem.rs.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250908185239.135849-3-lyude@redhat.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Now that my rust skills have been honed, I noticed that there's a lot of
generics in our gem bindings that don't actually need to be here. Currently
the hierarchy of traits in our gem bindings looks like this:

  * Drivers implement:
    * BaseDriverObject<T: DriverObject> (has the callbacks)
    * DriverObject (has the drm::Driver type)
  * Crate implements:
    * IntoGEMObject for Object<T> where T: DriverObject
      Handles conversion to/from raw object pointers
    * BaseObject for T where T: IntoGEMObject
      Provides methods common to all gem interfaces

  Also of note, this leaves us with two different drm::Driver associated
  types:
    * DriverObject::Driver
    * IntoGEMObject::Driver

I'm not entirely sure of the original intent here unfortunately (if anyone
is, please let me know!), but my guess is that the idea would be that some
objects can implement IntoGEMObject using a different ::Driver than
DriverObject - presumably to enable the usage of gem objects from different
drivers. A reasonable usecase of course.

However - if I'm not mistaken, I don't think that this is actually how
things would go in practice. Driver implementations are of course
implemented by their associated drivers, and generally drivers are not
linked to each-other when building the kernel. Which is to say that even in
a situation where we would theoretically deal with gem objects from another
driver, we still wouldn't have access to its drm::driver::Driver
implementation. It's more likely we would simply want a variant of gem
objects in such a situation that have no association with a
drm::driver::Driver type.

Taking that into consideration, we can assume the following:
* Anything that implements BaseDriverObject will implement DriverObject
  In other words, all BaseDriverObjects indirectly have an associated
  ::Driver type - so the two traits can be combined into one with no
  generics.
* Not everything that implements IntoGEMObject will have an associated
  ::Driver, and that's OK.

And with this, we now can do quite a bit of cleanup with the use of
generics here. As such, this commit:

* Removes the generics on BaseDriverObject
* Moves DriverObject::Driver into BaseDriverObject
* Removes DriverObject
* Removes IntoGEMObject::Driver
* Add AllocImpl::Driver, which we can use as a binding to figure out the
  correct File type for BaseObject

Leaving us with a simpler trait hierarchy that now looks like this:

  * Drivers implement: BaseDriverObject
  * Crate implements:
    * IntoGEMObject for Object<T> where T: DriverObject
    * BaseObject for T where T: IntoGEMObject

Which makes the code a lot easier to understand and build on :).

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250908185239.135849-2-lyude@redhat.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>

These `srctree/` links pointed inside `linux/`, but they are directly
under `drm/`.

Thus fix them.

This cleans a future warning that will check our `srctree/` links.

Cc: stable@vger.kernel.org
Fixes: a98a73be9ee9 ("rust: drm: file: Add File abstraction")
Fixes: c284d3e42338 ("rust: drm: gem: Add GEM object abstraction")
Fixes: 07c9016085f9 ("rust: drm: add driver abstractions")
Fixes: 1e4b8896c0f3 ("rust: drm: add device abstraction")
Fixes: 9a69570682b1 ("rust: drm: ioctl: Add DRM ioctl abstraction")
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Update call sites in drm to import `ARef` and
`AlwaysRefCounted` from `sync::aref` instead of `types`.

This aligns with the ongoing effort to move `ARef` and
`AlwaysRefCounted` to sync.

Suggested-by: Benno Lossin <lossin@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1173
Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/r/20250815161706.1324860-1-shankari.ak0208@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Enable a set of Clippy lints: 'ptr_as_ptr', 'ptr_cast_constness',
     'as_ptr_cast_mut', 'as_underscore', 'cast_lossless' and
     'ref_as_ptr'

     These are intended to avoid type casts with the 'as' operator,
     which are quite powerful, into restricted variants that are less
     powerful and thus should help to avoid mistakes

   - Remove the 'author' key now that most instances were moved to the
     plural one in the previous cycle

  'kernel' crate:

   - New 'bug' module: add 'warn_on!' macro which reuses the existing
     'BUG'/'WARN' infrastructure, i.e. it respects the usual sysctls and
     kernel parameters:

         warn_on!(value == 42);

     To avoid duplicating the assembly code, the same strategy is
     followed as for the static branch code in order to share the
     assembly between both C and Rust

     This required a few rearrangements on C arch headers -- the
     existing C macros should still generate the same outputs, thus no
     functional change expected there

   - 'workqueue' module: add delayed work items, including a
     'DelayedWork' struct, a 'impl_has_delayed_work!' macro and an
     'enqueue_delayed' method, e.g.:

         /// Enqueue the struct for execution on the system workqueue,
         /// where its value will be printed 42 jiffies later.
         fn print_later(value: Arc<MyStruct>) {
             let _ = workqueue::system().enqueue_delayed(value, 42);
         }

   - New 'bits' module: add support for 'bit' and 'genmask' functions,
     with runtime- and compile-time variants, e.g.:

         static_assert!(0b00010000 == bit_u8(4));
         static_assert!(0b00011110 == genmask_u8(1..=4));

         assert!(checked_bit_u32(u32::BITS).is_none());

   - 'uaccess' module: add 'UserSliceReader::strcpy_into_buf', which
     reads NUL-terminated strings from userspace into a '&CStr'

     Introduce 'UserPtr' newtype, similar in purpose to '__user' in C,
     to minimize mistakes handling userspace pointers, including mixing
     them up with integers and leaking them via the 'Debug' trait. Add
     it to the prelude, too

   - Start preparations for the replacement of our custom 'CStr' type
     with the analogous type in the 'core' standard library. This will
     take place across several cycles to make it easier. For this one,
     it includes a new 'fmt' module, using upstream method names and
     some other cleanups

     Replace 'fmt!' with a re-export, which helps Clippy lint properly,
     and clean up the found 'uninlined-format-args' instances

   - 'dma' module:

      - Clarify wording and be consistent in 'coherent' nomenclature

      - Convert the 'read!()' and 'write!()' macros to return a 'Result'

      - Add 'as_slice()', 'write()' methods in 'CoherentAllocation'

      - Expose 'count()' and 'size()' in 'CoherentAllocation' and add
        the corresponding type invariants

      - Implement 'CoherentAllocation::dma_handle_with_offset()'

   - 'time' module:

      - Make 'Instant' generic over clock source. This allows the
        compiler to assert that arithmetic expressions involving the
        'Instant' use 'Instants' based on the same clock source

      - Make 'HrTimer' generic over the timer mode. 'HrTimer' timers
        take a 'Duration' or an 'Instant' when setting the expiry time,
        depending on the timer mode. With this change, the compiler can
        check the type matches the timer mode

      - Add an abstraction for 'fsleep'. 'fsleep' is a flexible sleep
        function that will select an appropriate sleep method depending
        on the requested sleep time

      - Avoid 64-bit divisions on 32-bit hardware when calculating
        timestamps

      - Seal the 'HrTimerMode' trait. This prevents users of the
        'HrTimerMode' from implementing the trait on their own types

      - Pass the correct timer mode ID to 'hrtimer_start_range_ns()'

   - 'list' module: remove 'OFFSET' constants, allowing to remove
     pointer arithmetic; now 'impl_list_item!' invokes
     'impl_has_list_links!' or 'impl_has_list_links_self_ptr!'. Other
     simplifications too

   - 'types' module: remove 'ForeignOwnable::PointedTo' in favor of a
     constant, which avoids exposing the type of the opaque pointer, and
     require 'into_foreign' to return non-null

     Remove the 'Either<L, R>' type as well. It is unused, and we want
     to encourage the use of custom enums for concrete use cases

   - 'sync' module: implement 'Borrow' and 'BorrowMut' for 'Arc' types
     to allow them to be used in generic APIs

   - 'alloc' module: implement 'Borrow' and 'BorrowMut' for 'Box<T, A>';
     and 'Borrow', 'BorrowMut' and 'Default' for 'Vec<T, A>'

   - 'Opaque' type: add 'cast_from' method to perform a restricted cast
     that cannot change the inner type and use it in callers of
     'container_of!'. Rename 'raw_get' to 'cast_into' to match it

   - 'rbtree' module: add 'is_empty' method

   - 'sync' module: new 'aref' submodule to hold 'AlwaysRefCounted' and
     'ARef', which are moved from the too general 'types' module which
     we want to reduce or eventually remove. Also fix a safety comment
     in 'static_lock_class'

  'pin-init' crate:

   - Add 'impl<T, E> [Pin]Init<T, E> for Result<T, E>', so results are
     now (pin-)initializers

   - Add 'Zeroable::init_zeroed()' that delegates to 'init_zeroed()'

   - New 'zeroed()', a safe version of 'mem::zeroed()' and also provide
     it via 'Zeroable::zeroed()'

   - Implement 'Zeroable' for 'Option<&T>', 'Option<&mut T>' and for
     'Option<[unsafe] [extern "abi"] fn(...args...) -> ret>' for
     '"Rust"' and '"C"' ABIs and up to 20 arguments

   - Changed blanket impls of 'Init' and 'PinInit' from 'impl<T, E>
     [Pin]Init<T, E> for T' to 'impl<T> [Pin]Init<T> for T'

   - Renamed 'zeroed()' to 'init_zeroed()'

   - Upstream dev news: improve CI more to deny warnings, use
     '--all-targets'. Check the synchronization status of the two
     '-next' branches in upstream and the kernel

  MAINTAINERS:

   - Add Vlastimil Babka, Liam R. Howlett, Uladzislau Rezki and Lorenzo
     Stoakes as reviewers (thanks everyone)

  And a few other cleanups and improvements"

* tag 'rust-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (76 commits)
  rust: Add warn_on macro
  arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  rust: kernel: move ARef and AlwaysRefCounted to sync::aref
  rust: sync: fix safety comment for `static_lock_class`
  rust: types: remove `Either<L, R>`
  rust: kernel: use `core::ffi::CStr` method names
  rust: str: add `CStr` methods matching `core::ffi::CStr`
  rust: str: remove unnecessary qualification
  rust: use `kernel::{fmt,prelude::fmt!}`
  rust: kernel: add `fmt` module
  rust: kernel: remove `fmt!`, fix clippy::uninlined-format-args
  scripts: rust: emit path candidates in panic message
  scripts: rust: replace length checks with match
  rust: list: remove nonexistent generic parameter in link
  rust: bits: add support for bits/genmask macros
  rust: list: remove OFFSET constants
  rust: list: add `impl_list_item!` examples
  rust: list: use fully qualified path
  ...

Since commit b20fbbc08a36 ("rust: check type of `$ptr` in
`container_of!`") we have enforced that the field pointer passed to
container_of! must match the declared field. This caused mismatches when
using a pointer to bindings::x for fields of type Opaque<bindings::x>.

This situation encourages the user to simply pass field.cast() to the
container_of! macro, but this is not great because you might
accidentally pass a *mut bindings::y when the field type is
Opaque<bindings::x>, which would be wrong.

To help catch this kind of mistake, add a new Opaque::cast_from that
wraps a raw pointer in Opaque without changing the inner type. Also
update the docs to reflect this as well as some existing users.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250624-opaque-from-raw-v2-1-e4da40bdc59c@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>