This picks up from Michal Rostecki's work[0]. Per Michal's guidance I
have omitted Co-authored tags, as the end result is quite different.

This series is intended to be taken through rust-next. The final patch
in the series requires some other subsystems' `Acked-by`s:
- rust/kernel/device.rs: driver-core. Already acked by gregkh.
- rust/kernel/firmware.rs: driver-core. Danilo, could you take a look?
- rust/kernel/seq_file.rs: vfs, I think? missing MAINTAINERS entry.
  Christian Brauner <brauner@kernel.org>, perhaps?
- rust/kernel/sync/*: no clear owner, probably doesn't need any.

This series depends on steps 2a[1] and 2b[2] which both depend on step
1[3].

Link: https://lore.kernel.org/rust-for-linux/20240819153656.28807-2-vadorovsky@protonmail.com/t/#u [0]
Link: https://lore.kernel.org/all/20250709-core-cstr-fanout-1-v1-0-64308e7203fc@gmail.com/ [1]
Link: https://lore.kernel.org/all/20250709-core-cstr-fanout-1-v1-0-fd793b3e58a2@gmail.com/ [2]
Link: https://lore.kernel.org/all/20250704-core-cstr-prepare-v1-0-a91524037783@gmail.com/ [3]
Closes: https://github.com/Rust-for-Linux/linux/issues/1075

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
Changes in v14:
- Break the change into multiple series.
- Move `CStr` reexport to `kernel::ffi`. (Alice Ryhl)
- `pub use core::fmt::{....}` in `kernel/fmt.rs`. (Benno Lossin)
- Avoid unnecessary binding to `first_lit` in `fmt!`. (Benno Lossin)
- Add comment to `identifier`-extracting loop. (Benno Lossin)
- Change `quote_spanned!` formatting. (Benno Lossin)
- Link to v13: https://lore.kernel.org/r/20250701-cstr-core-v13-0-29f7d3eb97a6@gmail.com

Changes in v13:
- Rebase on v6.16-rc4.
- Link to v12: https://lore.kernel.org/r/20250619-cstr-core-v12-0-80c9c7b45900@gmail.com

Changes in v12:
- Introduce `kernel::fmt::Display` to allow implementations on foreign
  types.
- Tidy up doc comment on `str_to_cstr`. (Alice Ryhl).
- Link to v11: https://lore.kernel.org/r/20250530-cstr-core-v11-0-cd9c0cbcb902@gmail.com

Changes in v11:
- Use `quote_spanned!` to avoid `use<'a, T>` and generally reduce manual
  token construction.
- Add a commit to simplify `quote_spanned!`.
- Drop first commit in favor of
  https://lore.kernel.org/rust-for-linux/20240906164448.2268368-1-paddymills@proton.me/.
  (Miguel Ojeda)
- Correctly handle expressions such as `pr_info!("{a}", a = a = a)`.
  (Benno Lossin)
- Avoid dealing with `}}` escapes, which is not needed. (Benno Lossin)
- Revert some unnecessary changes. (Benno Lossin)
- Rename `c_str_avoid_literals!` to `str_to_cstr!`. (Benno Lossin &
  Alice Ryhl).
- Link to v10: https://lore.kernel.org/r/20250524-cstr-core-v10-0-6412a94d9d75@gmail.com

Changes in v10:
- Rebase on cbeaa41dfe26b72639141e87183cb23e00d4b0dd.
- Implement Alice's suggestion to use a proc macro to work around orphan
  rules otherwise preventing `core::ffi::CStr` to be directly printed
  with `{}`.
- Link to v9: https://lore.kernel.org/r/20250317-cstr-core-v9-0-51d6cc522f62@gmail.com

Changes in v9:
- Rebase on rust-next.
- Restore `impl Display for BStr` which exists upstream[1].
- Link: https://doc.rust-lang.org/nightly/std/bstr/struct.ByteStr.html#impl-Display-for-ByteStr [1]
- Link to v8: https://lore.kernel.org/r/20250203-cstr-core-v8-0-cb3f26e78686@gmail.com

Changes in v8:
- Move `{from,as}_char_ptr` back to `CStrExt`. This reduces the diff
  some.
- Restore `from_bytes_with_nul_unchecked_mut`, `to_cstring`.
- Link to v7: https://lore.kernel.org/r/20250202-cstr-core-v7-0-da1802520438@gmail.com

Changes in v7:
- Rebased on mainline.
- Restore functionality added in commit a321f3ad0a5d ("rust: str: add
  {make,to}_{upper,lower}case() to CString").
- Used `diff.algorithm patience` to improve diff readability.
- Link to v6: https://lore.kernel.org/r/20250202-cstr-core-v6-0-8469cd6d29fd@gmail.com

Changes in v6:
- Split the work into several commits for ease of review.
- Restore `{from,as}_char_ptr` to allow building on ARM (see commit
  message).
- Add `CStrExt` to `kernel::prelude`. (Alice Ryhl)
- Remove `CStrExt::from_bytes_with_nul_unchecked_mut` and restore
  `DerefMut for CString`. (Alice Ryhl)
- Rename and hide `kernel::c_str!` to encourage use of C-String
  literals.
- Drop implementation and invocation changes in kunit.rs. (Trevor Gross)
- Drop docs on `Display` impl. (Trevor Gross)
- Rewrite docs in the style of the standard library.
- Restore the `test_cstr_debug` unit tests to demonstrate that the
  implementation has changed.

Changes in v5:
- Keep the `test_cstr_display*` unit tests.

Changes in v4:
- Provide the `CStrExt` trait with `display()` method, which returns a
   `CStrDisplay` wrapper with `Display` implementation. This addresses
   the lack of `Display` implementation for `core::ffi::CStr`.
- Provide `from_bytes_with_nul_unchecked_mut()` method in `CStrExt`,
   which might be useful and is going to prevent manual, unsafe casts.
- Fix a typo (s/preffered/prefered/).

Changes in v3:
- Fix the commit message.
- Remove redundant braces in `use`, when only one item is imported.

Changes in v2:
- Do not remove `c_str` macro. While it's preferred to use C-string
   literals, there are two cases where `c_str` is helpful:
   - When working with macros, which already return a Rust string literal
     (e.g. `stringify!`).
   - When building macros, where we want to take a Rust string literal as an
     argument (for caller's convenience), but still use it as a C-string
     internally.
- Use Rust literals as arguments in macros (`new_mutex`, `new_condvar`,
   `new_mutex`). Use the `c_str` macro to convert these literals to C-string
   literals.
- Use `c_str` in kunit.rs for converting the output of `stringify!` to a
   `CStr`.
- Remove `DerefMut` implementation for `CString`.

---
Tamir Duberstein (3):
      rust: macros: reduce collections in `quote!` macro
      rust: support formatting of foreign types
      rust: replace `CStr` with `core::ffi::CStr`

 rust/ffi.rs                     |   2 +
 rust/kernel/device.rs           |   1 +
 rust/kernel/error.rs            |   2 +
 rust/kernel/firmware.rs         |   9 +-
 rust/kernel/fmt.rs              |  87 ++++++++-
 rust/kernel/prelude.rs          |   7 +-
 rust/kernel/seq_file.rs         |   2 +-
 rust/kernel/str.rs              | 395 +++++++++-------------------------------
 rust/kernel/sync/condvar.rs     |   2 +-
 rust/kernel/sync/lock.rs        |   2 +-
 rust/kernel/sync/lock/global.rs |   2 +-
 rust/macros/fmt.rs              |  94 ++++++++++
 rust/macros/lib.rs              |  19 ++
 rust/macros/quote.rs            | 111 +++++------
 14 files changed, 362 insertions(+), 373 deletions(-)
---
base-commit: 769e324b66b0d92d04f315d0c45a0f72737c7494
change-id: 20250201-cstr-core-d4b9b69120cf
prerequisite-change-id: 20250704-core-cstr-prepare-9b9e6a7bd57e:v1
prerequisite-patch-id: 83b1239d1805f206711a5a936bbb61c83227d573
prerequisite-patch-id: a0355dd0efcc945b0565dc4e5a0f42b5a3d29c7e
prerequisite-patch-id: 8585bf441cfab705181f5606c63483c2e88d25aa
prerequisite-patch-id: 04ec344c0bc23f90dbeac10afe26df1a86ce53ec
prerequisite-patch-id: a2fc6cd05fce6d6da8d401e9f8a905bb5c0b2f27
prerequisite-patch-id: f14c099c87562069f25fb7aea6d9aae4086c49a8
prerequisite-message-id: 20250709-core-cstr-fanout-1-v1-0-64308e7203fc@gmail.com
prerequisite-patch-id: fa79c5d8fd2762b5e488ba017e13a5774d933f81
prerequisite-patch-id: c338aa49e1319e9e802de2ad8bb0fa688bce9d9c
prerequisite-patch-id: 589a352ba7f7c9aefefd84dfd3b6b20e290b0d14
prerequisite-patch-id: 29fc25261295349f6747d1bb409cf18130e9aa69
prerequisite-patch-id: 3d89601bba1fb01d190b0ba415b28ad9cbf1e209
prerequisite-patch-id: 10923aebf24011b727f60496c0f9e0ad57e0a967
prerequisite-patch-id: 56583fd829951fb4fac843c6b1874c643b726de0
prerequisite-patch-id: 9a7e8ba460358985147efd347658be31fbc78ba2
prerequisite-patch-id: 5821a23334e317cd0351b8e4404b9e3b36b72d67
prerequisite-message-id: 20250709-core-cstr-fanout-1-v1-0-fd793b3e58a2@gmail.com
prerequisite-patch-id: 0ccc3545ff9bf22a67b79a944705cef2fb9c2bbf
prerequisite-patch-id: b1866166714606d5c11a4d7506abe4c2f86dac8d
prerequisite-patch-id: 163b8ff1edaf8e48976fd5de3f64e68fc38c7277
prerequisite-patch-id: 8fee5e2daf0749362331dad4fc63d907a01b14e9
prerequisite-patch-id: 366ef1f93fb40b1d039768f2041ff79995e7e228
prerequisite-patch-id: 1d350291f9292f910081856d8f7d5e4d9545cfd1
prerequisite-patch-id: 9a6a60bd2b209126de64c16a77a3a1d229dd898c
prerequisite-patch-id: 08ae5855768ec3b4c68272b86d2a0e0667c9aa47
prerequisite-patch-id: f15b54927660a03b52ffb34fb7943ac3228b7803
prerequisite-patch-id: f0dbf0a55a27fe8e199e242d1f79ea800d1ddb66

Best regards,
--  
Tamir Duberstein <tamird@gmail.com>

On Thu Jul 10, 2025 at 4:53 PM CEST, Tamir Duberstein wrote:
> This picks up from Michal Rostecki's work[0]. Per Michal's guidance I
> have omitted Co-authored tags, as the end result is quite different.

For device and firmware,

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