Starting with Rust 1.98.0 (expected 2026-08-20), the compiler has changed
how the resolution algorithm works [1] in upstream commit c4d84db5f184
("Resolver: Batched import resolution."), and it now spots:

    error: unused import: `flags::*`
     --> rust/kernel/str.rs:7:9
      |
    7 |         flags::*,
      |         ^^^^^^^^
      |
      = note: `-D unused-imports` implied by `-D warnings`
      = help: to override `-D warnings` add `#[allow(unused_imports)]`

It happens to not be needed because the `prelude::*` already provides
the flags.

Thus clean it up.

Cc: stable@vger.kernel.org # Needed in 6.18.y and later (prelude added to `str`).
Link: https://github.com/rust-lang/rust/pull/145108 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260609104152.261145-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Convert the imports to use the "kernel vertical" imports style [1].

No functional changes intended.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260609104152.261145-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

There are 6 individual Rust KUnit test suites (plus the doctests one). All
the tests are compiled unconditionally now, which adds ~200 kB to the
kernel image for me on x86_64. As Rust matures, this bloating will
inevitably grow.

Add Kconfig.test which includes a RUST_KUNIT_TESTS menu, and all
individual tests under it.

As usual, new tests are all enabled if KUNIT_ALL_TESTS=y.

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Reviewed-by: David Gow <david@davidgow.net>
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260417031531.315281-3-ynorov@nvidia.com
[ Fixed capitalization. Used singular for "API" for consistency.
  Reworded to clarify these are suites and that there exists
  the doctests one (which is the biggest at the moment by
  far). - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Pull timekeeping updates from Andreas Hindborg:

 - Expand the example section in the 'HrTimer' documentation.

 - Mark the 'ClockSource' trait as unsafe to ensure valid values for
   'ktime_get()'.

 - Add 'Delta::from_nanos()'.

This is a back merge since the pull request has a newer base -- we will
avoid that in the future.

And, given it is a back merge, it happens to resolve the "subtle" conflict
around '--remap-path-{prefix,scope}' that I discussed in linux-next [1],
plus a few other common conflicts. The result matches what we did for
next-20260407.

The actual diffstat (i.e. using a temporary merge of upstream first) is:

    rust/kernel/time.rs         |  32 ++++-
    rust/kernel/time/hrtimer.rs | 336 ++++++++++++++++++++++++++++++++++++++++++++
    2 files changed, 362 insertions(+), 6 deletions(-)

Link: https://lore.kernel.org/linux-next/CANiq72kdxB=W3_CV1U44oOK3SssztPo2wLDZt6LP94TEO+Kj4g@mail.gmail.com/ [1]

* tag 'rust-timekeeping-for-v7.1' of https://github.com/Rust-for-Linux/linux:
  hrtimer: add usage examples to documentation
  rust: time: make ClockSource unsafe trait
  rust/time: Add Delta::from_nanos()

Improve the safety comment for the `inc_len()` call in
`CString::try_from_fmt()` to clarify why `bytes_written()` is
guaranteed not to exceed the buffer capacity.

The current comment states that bytes written is bounded by size,
but does not explain that this invariant is maintained because:
1. The `Formatter` is created with `size` as its capacity limit
2. The `?` operators on `write_fmt` and `write_str` ensure early
   return if writing exceeds this limit

Suggested-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/rust-for-linux/20221114145329.0f47a3ab@GaryWorkstation/
Link: https://github.com/Rust-for-Linux/linux/issues/936
Signed-off-by: Nakamura Shuta <nakamura.shuta@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260119062925.1647-1-nakamura.shuta@gmail.com
[ Updated tags: it was a suggestion from Gary from the mailing list
  (the linked issue is mostly about adding a `debug_assert_eq!`).
    - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Now that all literals are C-Strings, update the documentation to explain
that use of this macro should be limited to non-literal strings.

Link: https://github.com/Rust-for-Linux/linux/issues/1075
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260309-cstr-rename-macro-v2-1-25f7de75944e@kernel.org
[ Apply sentence case to comment. Reword title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

As kernel always use unsigned char and not the platform ABI's default, an
user should always use `as_char_ptr` provided via `CStrExt` instead.
Therefore configure `disallow-methods` feature of clippy to catch incorrect
usage.

Similarly, the dual `from_ptr` is also disallowed.

[ As an example, without the previous commit, we would get a warning like:

      warning: use of a disallowed method `core::ffi::CStr::as_ptr`
         --> rust/kernel/task.rs:422:54
          |
      422 |         unsafe { crate::bindings::__might_sleep(file.as_ptr().cast(), loc.line() as i32) }
          |                                                      ^^^^^^ help: kernel's `char` is always unsigned, use `as_char_ptr` instead: `kernel::prelude::CStrExt::as_char_ptr`
          |
          = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.94.0/index.html#disallowed_methods
          = note: `-W clippy::disallowed-methods` implied by `-W clippy::all`
          = help: to override `-W clippy::all` add `#[allow(clippy::disallowed_methods)]`

    - Miguel ]

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Link: https://patch.msgid.link/20260203130745.868762-2-gary@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

If `CONFIG_BLOCK` is disabled, the following warnings are displayed
during build:

  warning: struct `NullTerminatedFormatter` is never constructed
    --> ../rust/kernel/str.rs:667:19
      |
  667 | pub(crate) struct NullTerminatedFormatter<'a> {
      |                   ^^^^^^^^^^^^^^^^^^^^^^^
      |
      = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default

  warning: associated function `new` is never used
    --> ../rust/kernel/str.rs:673:19
      |
  671 | impl<'a> NullTerminatedFormatter<'a> {
      | ------------------------------------ associated function in this implementation
  672 |     /// Create a new [`Self`] instance.
  673 |     pub(crate) fn new(buffer: &'a mut [u8]) -> Option<NullTerminatedFormatter<'a>> {

Fix them by making `NullTerminatedFormatter` public, as it could be
useful for drivers anyway.

Fixes: cdde7a1951ff ("rust: str: introduce `NullTerminatedFormatter`")
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260224-nullterminatedformatter-v1-1-5bef7b9b3d4c@nvidia.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Pull module updates from Daniel Gomez:
 "Rust module parameter support:

   - Add Rust module parameter support, enabling Rust kernel modules to
     declare and use module parameters. The rust_minimal sample module
     demonstrates this, and the rust null block driver will be the first
     to use it in the next cycle. This also adds the Rust module files
     under the modules subsystem as agreed between the Rust and modules
     maintainers.

  Hardening:

   - Add compile-time check for embedded NUL characters in MODULE_*()
     macros. This module metadata was once used (and maybe still) to
     bypass license enforcement (LWN article from 2003):

	https://lwn.net/Articles/82305/ [1]

  MAINTAINERS:

   - Add Aaron Tomlin as reviewer for the Modules subsystem"

* tag 'modules-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
  MAINTAINERS: Add myself as reviewer for module support
  module: Add compile-time check for embedded NUL characters
  media: radio: si470x: Fix DRIVER_AUTHOR macro definition
  media: dvb-usb-v2: lmedm04: Fix firmware macro definitions
  modules: add rust modules files to MAINTAINERS
  rust: samples: add a module parameter to the rust_minimal sample
  rust: module: update the module macro with module parameter support
  rust: module: use a reference in macros::module::module
  rust: introduce module_param module
  rust: str: add radix prefixed integer parsing functions
  rust: sync: add `SetOnce`

C-String literals were added in Rust 1.77. Replace instances of
`kernel::c_str!` with C-String literals where possible.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Link: https://patch.msgid.link/20251113-core-cstr-cstrings-v3-3-411b34002774@gmail.com
[ Removed unused `c_str` import in doctest. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>