rust: lockdep: Use Pin for all LockClassKey usages

Reintroduce dynamically-allocated LockClassKeys such that they are
automatically (de)registered. Require that all usages of LockClassKeys
ensure th

rust: lockdep: Use Pin for all LockClassKey usages

Reintroduce dynamically-allocated LockClassKeys such that they are
automatically (de)registered. Require that all usages of LockClassKeys
ensure that they are Pin'd.

Currently, only `'static` LockClassKeys are supported, so Pin is
redundant. However, it is intended that dynamically-allocated
LockClassKeys will eventually be supported, so using Pin from the outset
will make that change simpler.

Closes: https://github.com/Rust-for-Linux/linux/issues/1102
Suggested-by: Benno Lossin <[email protected]>
Suggested-by: Boqun Feng <[email protected]>
Signed-off-by: Mitchell Levy <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

rust: lockdep: Remove support for dynamically allocated LockClassKeys

Currently, dynamically allocated LockCLassKeys can be used from the Rust
side without having them registered. This is a soundnes

rust: lockdep: Remove support for dynamically allocated LockClassKeys

Currently, dynamically allocated LockCLassKeys can be used from the Rust
side without having them registered. This is a soundness issue, so
remove them.

Fixes: 6ea5aa08857a ("rust: sync: introduce `LockClassKey`")
Suggested-by: Alice Ryhl <[email protected]>
Signed-off-by: Mitchell Levy <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]

show more ...

rust: add rcu abstraction

Add a simple abstraction to guard critical code sections with an rcu
read lock.

Reviewed-by: Boqun Feng <[email protected]>
Signed-off-by: Wedson Almeida Filho <wedsona

rust: add rcu abstraction

Add a simple abstraction to guard critical code sections with an rcu
read lock.

Reviewed-by: Boqun Feng <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Danilo Krummrich <[email protected]>
Signed-off-by: Danilo Krummrich <[email protected]>
Tested-by: Dirk Behme <[email protected]>
Tested-by: Fabien Parent <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

rust: sync: Add SpinLockGuard type alias

A simple helper alias for code that needs to deal with Guard types returned
from SpinLocks.

Signed-off-by: Lyude Paul <[email protected]>
Reviewed-by: Alice

rust: sync: Add SpinLockGuard type alias

A simple helper alias for code that needs to deal with Guard types returned
from SpinLocks.

Signed-off-by: Lyude Paul <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

rust: sync: Add MutexGuard type alias

A simple helper alias for code that needs to deal with Guard types returned
from Mutexes.

Signed-off-by: Lyude Paul <[email protected]>
Reviewed-by: Alice Ryhl

rust: sync: Add MutexGuard type alias

A simple helper alias for code that needs to deal with Guard types returned
from Mutexes.

Signed-off-by: Lyude Paul <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

rust: sync: add global lock support

Add support for creating global variables that are wrapped in a mutex or
spinlock.

The implementation here is intended to replace the global mutex
workaround fou

rust: sync: add global lock support

Add support for creating global variables that are wrapped in a mutex or
spinlock.

The implementation here is intended to replace the global mutex
workaround found in the Rust Binder RFC [1]. In both cases, the global
lock must be initialized before first use. The macro is unsafe to use
for the same reason.

The separate initialization step is required because it is tricky to
access the value of __ARCH_SPIN_LOCK_UNLOCKED from Rust. Doing so will
require changes to the C side. That change will happen as a follow-up to
this patch.

Link: https://lore.kernel.org/rust-for-linux/[email protected]/#Z31drivers:android:context.rs [1]
Signed-off-by: Alice Ryhl <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Simplified a few intra-doc links. Formatted a few comments. Reworded
title. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: file: add abstraction for `poll_table`

The existing `CondVar` abstraction is a wrapper around
`wait_queue_head`, but it does not support all use-cases of the C
`wait_queue_head` type. To be sp

rust: file: add abstraction for `poll_table`

The existing `CondVar` abstraction is a wrapper around
`wait_queue_head`, but it does not support all use-cases of the C
`wait_queue_head` type. To be specific, a `CondVar` cannot be registered
with a `struct poll_table`. This limitation has the advantage that you
do not need to call `synchronize_rcu` when destroying a `CondVar`.

However, we need the ability to register a `poll_table` with a
`wait_queue_head` in Rust Binder. To enable this, introduce a type
called `PollCondVar`, which is like `CondVar` except that you can
register a `poll_table`. We also introduce `PollTable`, which is a safe
wrapper around `poll_table` that is intended to be used with
`PollCondVar`.

The destructor of `PollCondVar` unconditionally calls `synchronize_rcu`
to ensure that the removal of epoll waiters has fully completed before
the `wait_queue_head` is destroyed.

That said, `synchronize_rcu` is rather expensive and is not needed in
all cases: If we have never registered a `poll_table` with the
`wait_queue_head`, then we don't need to call `synchronize_rcu`. (And
this is a common case in Binder - not all processes use Binder with
epoll.) The current implementation does not account for this, but if we
find that it is necessary to improve this, a future patch could store a
boolean next to the `wait_queue_head` to keep track of whether a
`poll_table` has ever been registered.

Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Trevor Gross <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

show more ...

rust: sync: implement `Default` for `LockClassKey`

In the upcoming Rust 1.78.0, Clippy suggests to implement `Default` even
when `new()` is `const`, since `Default::default()` may call `const`
funct

rust: sync: implement `Default` for `LockClassKey`

In the upcoming Rust 1.78.0, Clippy suggests to implement `Default` even
when `new()` is `const`, since `Default::default()` may call `const`
functions even if it is not `const` itself [1]:

error: you should consider adding a `Default` implementation for `LockClassKey`
--> rust/kernel/sync.rs:31:5
|
31 | / pub const fn new() -> Self {
32 | | Self(Opaque::uninit())
33 | | }
| |_____^

Thus implement it.

Link: https://github.com/rust-lang/rust-clippy/pull/10903 [1]
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: kernel: add reexports for macros

Currently, all macros are reexported with #[macro_export] only, which
means that to access `new_work!` from the workqueue, you need to import
it from the path

rust: kernel: add reexports for macros

Currently, all macros are reexported with #[macro_export] only, which
means that to access `new_work!` from the workqueue, you need to import
it from the path `kernel::new_work` instead of importing it from the
workqueue module like all other items in the workqueue. By adding
reexports of the macros, it becomes possible to import the macros from
the correct modules.

It's still possible to import the macros from the root, but I don't
think we can do anything about that.

There is no functional change. This is merely a code cleanliness
improvement.

Signed-off-by: Alice Ryhl <[email protected]>
Reviewed-by: Trevor Gross <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Removed new `use kernel::prelude::*`s, reworded title. ]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: add `CondVar::wait_timeout`

Sleep on a condition variable with a timeout.

This is used by Rust Binder for process freezing. There, we want to
sleep until the freeze operation completes,

rust: sync: add `CondVar::wait_timeout`

Sleep on a condition variable with a timeout.

This is used by Rust Binder for process freezing. There, we want to
sleep until the freeze operation completes, but we want to be able to
abort the process freezing if it doesn't complete within some timeout.

Note that it is not enough to avoid jiffies by introducing a variant of
`CondVar::wait_timeout` that takes the timeout in msecs because we need
to be able to restart the sleep with the remaining sleep duration if it
is interrupted, and if the API takes msecs rather than jiffies, then
that would require a conversion roundtrip jiffies->msecs->jiffies that
is best avoided.

Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Tiago Lam <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Added `CondVarTimeoutResult` re-export and fixed typo. ]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: introduce `CondVar`

This is the traditional condition variable or monitor synchronisation
primitive. It is implemented with C's `wait_queue_head_t`.

It allows users to release a lock an

rust: sync: introduce `CondVar`

This is the traditional condition variable or monitor synchronisation
primitive. It is implemented with C's `wait_queue_head_t`.

It allows users to release a lock and go to sleep while guaranteeing
that notifications won't be missed. This is achieved by enqueuing a wait
entry before releasing the lock.

Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Waiman Long <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: introduce `LockedBy`

This allows us to have data protected by a lock despite not being
wrapped by it. Access is granted by providing evidence that the lock is
held by the caller.

Review

rust: sync: introduce `LockedBy`

This allows us to have data protected by a lock despite not being
wrapped by it. Access is granted by providing evidence that the lock is
held by the caller.

Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: lock: introduce `SpinLock`

This is the `spinlock_t` lock backend and allows Rust code to use the
kernel spinlock idiomatically.

Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <ming

rust: lock: introduce `SpinLock`

This is the `spinlock_t` lock backend and allows Rust code to use the
kernel spinlock idiomatically.

Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Waiman Long <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: lock: introduce `Mutex`

This is the `struct mutex` lock backend and allows Rust code to use the
kernel mutex idiomatically.

Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <mingo@re

rust: lock: introduce `Mutex`

This is the `struct mutex` lock backend and allows Rust code to use the
kernel mutex idiomatically.

Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Waiman Long <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: introduce `Lock` and `Guard`

They are generic Rust implementations of a lock and a lock guard that
contain code that is common to all locks. Different backends will be
introduced in subs

rust: sync: introduce `Lock` and `Guard`

They are generic Rust implementations of a lock and a lock guard that
contain code that is common to all locks. Different backends will be
introduced in subsequent commits.

Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Suggested-by: Gary Guo <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Fixed typo. ]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: introduce `LockClassKey`

It is a wrapper around C's `lock_class_key`, which is used by the
synchronisation primitives that are checked with lockdep. This is in
preparation for introducin

rust: sync: introduce `LockClassKey`

It is a wrapper around C's `lock_class_key`, which is used by the
synchronisation primitives that are checked with lockdep. This is in
preparation for introducing Rust abstractions for these primitives.

Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Waiman Long <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Co-developed-by: Boqun Feng <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: introduce `UniqueArc`

Since `Arc<T>` does not allow mutating `T` directly (i.e., without inner
mutability), it is currently not possible to do some initialisation of
`T` post constructio

rust: sync: introduce `UniqueArc`

Since `Arc<T>` does not allow mutating `T` directly (i.e., without inner
mutability), it is currently not possible to do some initialisation of
`T` post construction but before being shared.

`UniqueArc<T>` addresses this problem essentially being an `Arc<T>` that
has a refcount of 1 and is therefore writable. Once initialisation is
completed, it can be transitioned (without failure paths) into an
`Arc<T>`.

Suggested-by: Gary Guo <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Reviewed-by: Vincenzo Palazzo <[email protected]>
Acked-by: Boqun Feng <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: introduce `ArcBorrow`

This allows us to create references to a ref-counted allocation without
double-indirection and that still allow us to increment the refcount to
a new `Arc<T>`.

Sig

rust: sync: introduce `ArcBorrow`

This allows us to create references to a ref-counted allocation without
double-indirection and that still allow us to increment the refcount to
a new `Arc<T>`.

Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Acked-by: Boqun Feng <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Reviewed-by: Vincenzo Palazzo <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...

rust: sync: add `Arc` for ref-counted allocations

This is a basic implementation of `Arc` backed by C's `refcount_t`. It
allows Rust code to idiomatically allocate memory that is ref-counted.

Cc: W

rust: sync: add `Arc` for ref-counted allocations

This is a basic implementation of `Arc` backed by C's `refcount_t`. It
allows Rust code to idiomatically allocate memory that is ref-counted.

Cc: Will Deacon <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Mark Rutland <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Reviewed-by: Vincenzo Palazzo <[email protected]>
Acked-by: Boqun Feng <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

show more ...