linux.git/rust/kernel/str.rs, branch v6.18.21

rust: str: make NullTerminatedFormatter public

2026-03-19T15:08:24+00:00

commit 3ac88a9948792b092a4b11323e2abd1ecbe0cc68 upstream.

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> {

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 
Reviewed-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260224-nullterminatedformatter-v1-1-5bef7b9b3d4c@nvidia.com
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

rust: block: use `NullTerminatedFormatter`

2025-09-02T11:23:56+00:00

Use the new `NullTerminatedFormatter` to write the name of a `GenDisk` to
the name buffer. This new formatter automatically adds a trailing null
marker after the written characters, so we don't need to append that at the
call site any longer.

Reviewed-by: Alice Ryhl 
Reviewed-by: Daniel Almeida 
Signed-off-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-8-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe

rust: str: introduce `kstrtobool` function

2025-09-02T11:23:56+00:00

Add a Rust wrapper for the kernel's `kstrtobool` function that converts
common user inputs into boolean values.

Reviewed-by: Daniel Almeida 
Signed-off-by: Andreas Hindborg 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-5-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe

rust: str: introduce `NullTerminatedFormatter`

2025-09-02T11:23:56+00:00

Add `NullTerminatedFormatter`, a formatter that writes a null terminated
string to an array or slice buffer. Because this type needs to manage the
trailing null marker, the existing formatters cannot be used to implement
this type.

Reviewed-by: Alice Ryhl 
Reviewed-by: Daniel Almeida 
Signed-off-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-4-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe

rust: str: expose `str::{Formatter, RawFormatter}` publicly.

2025-09-02T11:23:56+00:00

rnull is going to make use of `str::Formatter` and `str::RawFormatter`, so
expose them with public visibility.

Reviewed-by: Alice Ryhl 
Reviewed-by: Daniel Almeida 
Signed-off-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-3-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe

rust: str: allow `str::Formatter` to format into `&mut [u8]`.

2025-09-02T11:23:56+00:00

Improve `Formatter` so that it can write to an array or slice buffer.

Reviewed-by: Daniel Almeida 
Reviewed-by: Alice Ryhl 
Signed-off-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-2-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe

rust: str: normalize imports in `str.rs`

2025-09-02T11:23:56+00:00

Clean up imports in `str.rs`. This makes future code manipulation more
manageable.

Reviewed-by: Alice Ryhl 
Reviewed-by: Daniel Almeida 
Signed-off-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-1-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe

rust: kernel: use `core::ffi::CStr` method names

2025-07-20T23:16:36+00:00

Prepare for `core::ffi::CStr` taking the place of `kernel::str::CStr` by
avoiding methods that only exist on the latter.

Also avoid `Deref for CStr` as that impl doesn't exist on
`core::ffi::CStr`.

Link: https://github.com/Rust-for-Linux/linux/issues/1075
Signed-off-by: Tamir Duberstein 
Reviewed-by: Benno Lossin 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-6-a91524037783@gmail.com
[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: str: add `CStr` methods matching `core::ffi::CStr`

2025-07-20T23:16:36+00:00

Prepare for replacing `CStr` with `core::ffi::CStr` by soft-deprecating
methods which don't exist on `core::ffi::CStr`.

We could keep `as_bytes{,_with_nul}` through an extension trait but
seeing as we have to introduce `as_char_ptr_in_const_context` as a free
function, we may as well introduce `to_bytes{,_with_nul}` here to allow
downstream code to migrate in one cycle rather than two.

Link: https://github.com/Rust-for-Linux/linux/issues/1075
Signed-off-by: Tamir Duberstein 
Reviewed-by: Benno Lossin 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-5-a91524037783@gmail.com
[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: str: remove unnecessary qualification

2025-07-20T23:16:36+00:00

`core::ffi::*` is in the prelude, which is imported here.

Signed-off-by: Tamir Duberstein 
Reviewed-by: Benno Lossin 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-4-a91524037783@gmail.com
Signed-off-by: Miguel Ojeda