linux.git/rust/kernel/sync/arc.rs, branch v6.6.132

rust: arc: add explicit `drop()` around `Box::from_raw()`

2024-02-16T18:10:43+00:00

commit 828176d037e29f813792a8b3ac1591834240e96f upstream.

`Box::from_raw()` is `#[must_use]`, which means the result cannot
go unused.

In Rust 1.71.0, this was not detected because the block expression
swallows the diagnostic [1]:

    unsafe { Box::from_raw(self.ptr.as_ptr()) };

It would have been detected, however, if the line had been instead:

    unsafe { Box::from_raw(self.ptr.as_ptr()); }

i.e. the semicolon being inside the `unsafe` block, rather than
outside.

In Rust 1.72.0, the compiler started warning about this [2], so
without this patch we will get:

        error: unused return value of `alloc::boxed::Box::::from_raw` that must be used
        --> rust/kernel/sync/arc.rs:302:22
        |
    302 |             unsafe { Box::from_raw(self.ptr.as_ptr()) };
        |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        |
        = note: call `drop(Box::from_raw(ptr))` if you intend to drop the `Box`
        = note: `-D unused-must-use` implied by `-D warnings`
    help: use `let _ = ...` to ignore the resulting value
        |
    302 |             unsafe { let _ = Box::from_raw(self.ptr.as_ptr()); };
        |                      +++++++                                 +

Thus add an add an explicit `drop()` as the `#[must_use]`'s
annotation suggests (instead of the more general help line).

Link: https://github.com/rust-lang/rust/issues/104253 [1]
Link: https://github.com/rust-lang/rust/pull/112529 [2]
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Gary Guo 
Reviewed-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Björn Roy Baron 
Link: https://lore.kernel.org/r/20230823160244.188033-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'linux-kselftest-kunit-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2023-08-29T01:56:38+00:00

Pull kunit updates from Shuah Khan:

 - add support for running Rust documentation tests as KUnit tests

 - make init, str, sync, types doctests compilable/testable

 - add support for attributes API which include speed, modules
   attributes, ability to filter and report attributes

 - add support for marking tests slow using attributes API

 - add attributes API documentation

 - fix a wild-memory-access bug in kunit_filter_suites() and a possible
   memory leak in kunit_filter_suites()

 - add support for counting number of test suites in a module, list
   action to kunit test modules, and test filtering on module tests

* tag 'linux-kselftest-kunit-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits)
  kunit: fix struct kunit_attr header
  kunit: replace KUNIT_TRIGGER_STATIC_STUB maro with KUNIT_STATIC_STUB_REDIRECT
  kunit: Allow kunit test modules to use test filtering
  kunit: Make 'list' action available to kunit test modules
  kunit: Report the count of test suites in a module
  kunit: fix uninitialized variables bug in attributes filtering
  kunit: fix possible memory leak in kunit_filter_suites()
  kunit: fix wild-memory-access bug in kunit_filter_suites()
  kunit: Add documentation of KUnit test attributes
  kunit: add tests for filtering attributes
  kunit: time: Mark test as slow using test attributes
  kunit: memcpy: Mark tests as slow using test attributes
  kunit: tool: Add command line interface to filter and report attributes
  kunit: Add ability to filter attributes
  kunit: Add module attribute
  kunit: Add speed attribute
  kunit: Add test attributes API structure
  MAINTAINERS: add Rust KUnit files to the KUnit entry
  rust: support running Rust documentation tests as KUnit ones
  rust: types: make doctests compilable/testable
  ...

rust: delete `ForeignOwnable::borrow_mut`

2023-08-04T15:10:50+00:00

We discovered that the current design of `borrow_mut` is problematic.
This patch removes it until a better solution can be found.

Specifically, the current design gives you access to a `&mut T`, which
lets you change where the `ForeignOwnable` points (e.g., with
`core::mem::swap`). No upcoming user of this API intended to make that
possible, making all of them unsound.

Signed-off-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Reviewed-by: Benno Lossin 
Reviewed-by: Martin Rodriguez Reboredo 
Fixes: 0fc4424d24a2 ("rust: types: introduce `ForeignOwnable`")
Link: https://lore.kernel.org/r/20230706094615.3080784-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: sync: make doctests compilable/testable

2023-07-19T15:32:41+00:00

Rust documentation tests are going to be build/run-tested
with the KUnit integration added in a future patch, thus
update them to make them compilable/testable so that we
may start enforcing it.

Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Björn Roy Baron 
Reviewed-by: Alice Ryhl 
Reviewed-by: David Gow 
Signed-off-by: Miguel Ojeda 
Signed-off-by: Shuah Khan

rust: sync: reword the `Arc` safety comment for `Sync`

2023-05-31T16:53:10+00:00

The safety comment on `impl Sync for Arc` references the Send safety
comment. This commit avoids that in case the two comments drift apart in
the future.

Suggested-by: Andreas Hindborg 
Signed-off-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Boqun Feng 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Benno Lossin 
Link: https://lore.kernel.org/r/20230531145939.3714886-3-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: sync: reword the `Arc` safety comment for `Send`

2023-05-31T16:53:10+00:00

The safety comment on `impl Send for Arc` talks about "directly"
accessing the value, when it really means "accessing the value with a
mutable reference". This commit clarifies that.

Suggested-by: Boqun Feng 
Signed-off-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Boqun Feng 
Reviewed-by: Gary Guo 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Benno Lossin 
Link: https://lore.kernel.org/r/20230531145939.3714886-2-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: sync: implement `AsRef` for `Arc`

2023-05-31T16:53:10+00:00

This trait lets you use `Arc` in code that is generic over smart
pointer types.

The `AsRef` trait should be implemented on all smart pointers. The
standard library also implements it on the ordinary `Arc`.

Co-developed-by: Wedson Almeida Filho 
Signed-off-by: Wedson Almeida Filho 
Signed-off-by: Alice Ryhl 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20230517200814.3157916-2-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: sync: add `Arc::ptr_eq`

2023-05-31T16:53:10+00:00

Add a method for comparing whether two `Arc` pointers reference the same
underlying object.

This comparison can already be done by getting a reference to the inner
values and comparing whether the references have the same address.
However, writing `Arc::ptr_eq(a, b)` is generally less error-prone than
doing the same check on the references, since you might otherwise
accidentally compare the two `&Arc` references instead, which wont
work because those are pointers to pointers to the inner value, when you
just want to compare the pointers to the inner value.

Also, this method might optimize better because getting a reference to
the inner value involves offsetting the pointer, which this method does
not need to do.

Co-developed-by: Wedson Almeida Filho 
Signed-off-by: Wedson Almeida Filho 
Signed-off-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20230517200814.3157916-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda

rust: arc: fix intra-doc link in `Arc::init`

2023-05-31T14:12:06+00:00

`Arc::init` refers to `Arc::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e7e81c ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: https://github.com/rust-lang/rust/issues/106142 [1]
Reviewed-by: Gary Guo 
Reviewed-by: Benno Lossin 
Reviewed-by: Martin Rodriguez Reboredo 
Reviewed-by: Björn Roy Baron 
Tested-by: Ariel Miculas 
Tested-by: David Gow 
Tested-by: Boqun Feng 
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda

rust: sync: add functions for initializing `UniqueArc>`

2023-04-12T16:41:05+00:00

Add two functions `init_with` and `pin_init_with` to
`UniqueArc>` to initialize the memory of already allocated
`UniqueArc`s. This is useful when you want to allocate memory check some
condition inside of a context where allocation is forbidden and then
conditionally initialize an object.

Signed-off-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20230408122429.1103522-16-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda