Merge tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

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

   - KUnit '#[test]'s:

      - Support KUnit-mapped 'assert!' macros.

        The support that landed last cycle was very basic, and the
        'assert!' macros panicked since they were the standard library
        ones. Now, they are mapped to the KUnit ones in a similar way to
        how is done for doctests, reusing the infrastructure there.

        With this, a failing test like:

            #[test]
            fn my_first_test() {
                assert_eq!(42, 43);
            }

        will report:

            # my_first_test: ASSERTION FAILED at rust/kernel/lib.rs:251
            Expected 42 == 43 to be true, but is false
            # my_first_test.speed: normal
            not ok 1 my_first_test

      - Support tests with checked 'Result' return types.

        The return value of test functions that return a 'Result' will
        be checked, thus one can now easily catch errors when e.g. using
        the '?' operator in tests.

        With this, a failing test like:

            #[test]
            fn my_test() -> Result {
                f()?;
                Ok(())
            }

        will report:

            # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321
            Expected is_test_result_ok(my_test()) to be true, but is false
            # my_test.speed: normal
            not ok 1 my_test

      - Add 'kunit_tests' to the prelude.

   - Clarify the remaining language unstable features in use.

   - Compile 'core' with edition 2024 for Rust >= 1.87.

   - Workaround 'bindgen' issue with forward references to 'enum' types.

   - objtool: relax slice condition to cover more 'noreturn' functions.

   - Use absolute paths in macros referencing 'core' and 'kernel'
     crates.

   - Skip '-mno-fdpic' flag for bindgen in GCC 32-bit arm builds.

   - Clean some 'doc_markdown' lint hits -- we may enable it later on.

  'kernel' crate:

   - 'alloc' module:

      - 'Box': support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>'
        if 'T' implements 'U'.

      - 'Vec': implement new methods (prerequisites for nova-core and
        binder): 'truncate', 'resize', 'clear', 'pop',
        'push_within_capacity' (with new error type 'PushError'),
        'drain_all', 'retain', 'remove' (with new error type
        'RemoveError'), insert_within_capacity' (with new error type
        'InsertError').

        In addition, simplify 'push' using 'spare_capacity_mut', split
        'set_len' into 'inc_len' and 'dec_len', add type invariant 'len
        <= capacity' and simplify 'truncate' using 'dec_len'.

   - 'time' module:

      - Morph the Rust hrtimer subsystem into the Rust timekeeping
        subsystem, covering delay, sleep, timekeeping, timers. This new
        subsystem has all the relevant timekeeping C maintainers listed
        in the entry.

      - Replace 'Ktime' with 'Delta' and 'Instant' types to represent a
        duration of time and a point in time.

      - Temporarily add 'Ktime' to 'hrtimer' module to allow 'hrtimer'
        to delay converting to 'Instant' and 'Delta'.

   - 'xarray' module:

      - Add a Rust abstraction for the 'xarray' data structure. This
        abstraction allows Rust code to leverage the 'xarray' to store
        types that implement 'ForeignOwnable'. This support is a
        dependency for memory backing feature of the Rust null block
        driver, which is waiting to be merged.

      - Set up an entry in 'MAINTAINERS' for the XArray Rust support.
        Patches will go to the new Rust XArray tree and then via the
        Rust subsystem tree for now.

      - Allow 'ForeignOwnable' to carry information about the pointed-to
        type. This helps asserting alignment requirements for the
        pointer passed to the foreign language.

   - 'container_of!': retain pointer mut-ness and add a compile-time
     check of the type of the first parameter ('$field_ptr').

   - Support optional message in 'static_assert!'.

   - Add C FFI types (e.g. 'c_int') to the prelude.

   - 'str' module: simplify KUnit tests 'format!' macro, convert
     'rusttest' tests into KUnit, take advantage of the '-> Result'
     support in KUnit '#[test]'s.

   - 'list' module: add examples for 'List', fix path of
     'assert_pinned!' (so far unused macro rule).

   - 'workqueue' module: remove 'HasWork::OFFSET'.

   - 'page' module: add 'inline' attribute.

  'macros' crate:

   - 'module' macro: place 'cleanup_module()' in '.exit.text' section.

  'pin-init' crate:

   - Add 'Wrapper<T>' trait for creating pin-initializers for wrapper
     structs with a structurally pinned value such as 'UnsafeCell<T>' or
     'MaybeUninit<T>'.

   - Add 'MaybeZeroable' derive macro to try to derive 'Zeroable', but
     not error if not all fields implement it. This is needed to derive
     'Zeroable' for all bindgen-generated structs.

   - Add 'unsafe fn cast_[pin_]init()' functions to unsafely change the
     initialized type of an initializer. These are utilized by the
     'Wrapper<T>' implementations.

   - Add support for visibility in 'Zeroable' derive macro.

   - Add support for 'union's in 'Zeroable' derive macro.

   - Upstream dev news: streamline CI, fix some bugs. Add new workflows
     to check if the user-space version and the one in the kernel tree
     have diverged. Use the issues tab [1] to track them, which should
     help folks report and diagnose issues w.r.t. 'pin-init' better.

       [1] https://github.com/rust-for-linux/pin-init/issues

  Documentation:

   - Testing: add docs on the new KUnit '#[test]' tests.

   - Coding guidelines: explain that '///' vs. '//' applies to private
     items too. Add section on C FFI types.

   - Quick Start guide: update Ubuntu instructions and split them into
     "25.04" and "24.04 LTS and older".

  And a few other cleanups and improvements"

* tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (78 commits)
  rust: list: Fix typo `much` in arc.rs
  rust: check type of `$ptr` in `container_of!`
  rust: workqueue: remove HasWork::OFFSET
  rust: retain pointer mut-ness in `container_of!`
  Documentation: rust: testing: add docs on the new KUnit `#[test]` tests
  Documentation: rust: rename `#[test]`s to "`rusttest` host tests"
  rust: str: take advantage of the `-> Result` support in KUnit `#[test]`'s
  rust: str: simplify KUnit tests `format!` macro
  rust: str: convert `rusttest` tests into KUnit
  rust: add `kunit_tests` to the prelude
  rust: kunit: support checked `-> Result`s in KUnit `#[test]`s
  rust: kunit: support KUnit-mapped `assert!` macros in `#[test]`s
  rust: make section names plural
  rust: list: fix path of `assert_pinned!`
  rust: compile libcore with edition 2024 for 1.87+
  rust: dma: add missing Markdown code span
  rust: task: add missing Markdown code spans and intra-doc links
  rust: pci: fix docs related to missing Markdown code spans
  rust: alloc: add missing Markdown code span
  rust: alloc: add missing Markdown code spans
  ...

1 files changed, 36 insertions, 46 deletions

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index fb61ce81ea28..a927db8e079c 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -6,7 +6,7 @@ use crate::alloc::{flags::*, AllocError, KVec};
 use core::fmt::{self, Write};
 use core::ops::{self, Deref, DerefMut, Index};
 
-use crate::error::{code::*, Error};
+use crate::prelude::*;
 
 /// Byte string without UTF-8 validity guarantee.
 #[repr(transparent)]
@@ -572,30 +572,13 @@ macro_rules! c_str {
     }};
 }
 
-#[cfg(test)]
-#[expect(clippy::items_after_test_module)]
+#[kunit_tests(rust_kernel_str)]
 mod tests {
     use super::*;
 
-    struct String(CString);
-
-    impl String {
-        fn from_fmt(args: fmt::Arguments<'_>) -> Self {
-            String(CString::try_from_fmt(args).unwrap())
-        }
-    }
-
-    impl Deref for String {
-        type Target = str;
-
-        fn deref(&self) -> &str {
-            self.0.to_str().unwrap()
-        }
-    }
-
     macro_rules! format {
         ($($f:tt)*) => ({
-            &*String::from_fmt(kernel::fmt!($($f)*))
+            CString::try_from_fmt(::kernel::fmt!($($f)*))?.to_str()?
         })
     }
 
@@ -614,67 +597,72 @@ mod tests {
         \\xf0\\xf1\\xf2\\xf3\\xf4\\xf5\\xf6\\xf7\\xf8\\xf9\\xfa\\xfb\\xfc\\xfd\\xfe\\xff";
 
     #[test]
-    fn test_cstr_to_str() {
+    fn test_cstr_to_str() -> Result {
         let good_bytes = b"\xf0\x9f\xa6\x80\0";
-        let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
-        let checked_str = checked_cstr.to_str().unwrap();
+        let checked_cstr = CStr::from_bytes_with_nul(good_bytes)?;
+        let checked_str = checked_cstr.to_str()?;
         assert_eq!(checked_str, "🦀");
+        Ok(())
     }
 
     #[test]
-    #[should_panic]
-    fn test_cstr_to_str_panic() {
+    fn test_cstr_to_str_invalid_utf8() -> Result {
         let bad_bytes = b"\xc3\x28\0";
-        let checked_cstr = CStr::from_bytes_with_nul(bad_bytes).unwrap();
-        checked_cstr.to_str().unwrap();
+        let checked_cstr = CStr::from_bytes_with_nul(bad_bytes)?;
+        assert!(checked_cstr.to_str().is_err());
+        Ok(())
     }
 
     #[test]
-    fn test_cstr_as_str_unchecked() {
+    fn test_cstr_as_str_unchecked() -> Result {
         let good_bytes = b"\xf0\x9f\x90\xA7\0";
-        let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+        let checked_cstr = CStr::from_bytes_with_nul(good_bytes)?;
         // SAFETY: The contents come from a string literal which contains valid UTF-8.
         let unchecked_str = unsafe { checked_cstr.as_str_unchecked() };
         assert_eq!(unchecked_str, "🐧");
+        Ok(())
     }
 
     #[test]
-    fn test_cstr_display() {
-        let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap();
+    fn test_cstr_display() -> Result {
+        let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0")?;
         assert_eq!(format!("{hello_world}"), "hello, world!");
-        let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap();
+        let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0")?;
         assert_eq!(format!("{non_printables}"), "\\x01\\x09\\x0a");
-        let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap();
+        let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0")?;
         assert_eq!(format!("{non_ascii}"), "d\\xe9j\\xe0 vu");
-        let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap();
+        let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0")?;
         assert_eq!(format!("{good_bytes}"), "\\xf0\\x9f\\xa6\\x80");
+        Ok(())
     }
 
     #[test]
-    fn test_cstr_display_all_bytes() {
+    fn test_cstr_display_all_bytes() -> Result {
         let mut bytes: [u8; 256] = [0; 256];
         // fill `bytes` with [1..=255] + [0]
         for i in u8::MIN..=u8::MAX {
             bytes[i as usize] = i.wrapping_add(1);
         }
-        let cstr = CStr::from_bytes_with_nul(&bytes).unwrap();
+        let cstr = CStr::from_bytes_with_nul(&bytes)?;
         assert_eq!(format!("{cstr}"), ALL_ASCII_CHARS);
+        Ok(())
     }
 
     #[test]
-    fn test_cstr_debug() {
-        let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0").unwrap();
+    fn test_cstr_debug() -> Result {
+        let hello_world = CStr::from_bytes_with_nul(b"hello, world!\0")?;
         assert_eq!(format!("{hello_world:?}"), "\"hello, world!\"");
-        let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0").unwrap();
+        let non_printables = CStr::from_bytes_with_nul(b"\x01\x09\x0a\0")?;
         assert_eq!(format!("{non_printables:?}"), "\"\\x01\\x09\\x0a\"");
-        let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0").unwrap();
+        let non_ascii = CStr::from_bytes_with_nul(b"d\xe9j\xe0 vu\0")?;
         assert_eq!(format!("{non_ascii:?}"), "\"d\\xe9j\\xe0 vu\"");
-        let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0").unwrap();
+        let good_bytes = CStr::from_bytes_with_nul(b"\xf0\x9f\xa6\x80\0")?;
         assert_eq!(format!("{good_bytes:?}"), "\"\\xf0\\x9f\\xa6\\x80\"");
+        Ok(())
     }
 
     #[test]
-    fn test_bstr_display() {
+    fn test_bstr_display() -> Result {
         let hello_world = BStr::from_bytes(b"hello, world!");
         assert_eq!(format!("{hello_world}"), "hello, world!");
         let escapes = BStr::from_bytes(b"_\t_\n_\r_\\_\'_\"_");
@@ -685,10 +673,11 @@ mod tests {
         assert_eq!(format!("{non_ascii}"), "d\\xe9j\\xe0 vu");
         let good_bytes = BStr::from_bytes(b"\xf0\x9f\xa6\x80");
         assert_eq!(format!("{good_bytes}"), "\\xf0\\x9f\\xa6\\x80");
+        Ok(())
     }
 
     #[test]
-    fn test_bstr_debug() {
+    fn test_bstr_debug() -> Result {
         let hello_world = BStr::from_bytes(b"hello, world!");
         assert_eq!(format!("{hello_world:?}"), "\"hello, world!\"");
         let escapes = BStr::from_bytes(b"_\t_\n_\r_\\_\'_\"_");
@@ -699,6 +688,7 @@ mod tests {
         assert_eq!(format!("{non_ascii:?}"), "\"d\\xe9j\\xe0 vu\"");
         let good_bytes = BStr::from_bytes(b"\xf0\x9f\xa6\x80");
         assert_eq!(format!("{good_bytes:?}"), "\"\\xf0\\x9f\\xa6\\x80\"");
+        Ok(())
     }
 }
 
@@ -752,7 +742,7 @@ impl RawFormatter {
     /// for the lifetime of the returned [`RawFormatter`].
     pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self {
         let pos = buf as usize;
-        // INVARIANT: We ensure that `end` is never less then `buf`, and the safety requirements
+        // INVARIANT: We ensure that `end` is never less than `buf`, and the safety requirements
         // guarantees that the memory region is valid for writes.
         Self {
             pos,
@@ -886,7 +876,7 @@ impl CString {
 
         // SAFETY: The number of bytes that can be written to `f` is bounded by `size`, which is
         // `buf`'s capacity. The contents of the buffer have been initialised by writes to `f`.
-        unsafe { buf.set_len(f.bytes_written()) };
+        unsafe { buf.inc_len(f.bytes_written()) };
 
         // Check that there are no `NUL` bytes before the end.
         // SAFETY: The buffer is valid for read because `f.bytes_written()` is bounded by `size`
@@ -944,5 +934,5 @@ impl fmt::Debug for CString {
 /// A convenience alias for [`core::format_args`].
 #[macro_export]
 macro_rules! fmt {
-    ($($f:tt)*) => ( core::format_args!($($f)*) )
+    ($($f:tt)*) => ( ::core::format_args!($($f)*) )
 }