Messages in this thread Patch in this message | | | From | Wedson Almeida Filho <> | Subject | [PATCH v3 07/13] rust: lock: implement `IrqSaveBackend` for `SpinLock` | Date | Sat, 8 Apr 2023 04:53:34 -0300 |
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From: Wedson Almeida Filho <walmeida@microsoft.com>
This allows Rust code to use the `lock_irqsave` variant of spinlocks.
Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Waiman Long <longman@redhat.com> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> --- v1 -> v2: No changes v2 -> v3: No changes
rust/helpers.c | 16 +++++++++++++ rust/kernel/sync/lock/spinlock.rs | 38 ++++++++++++++++++++++++++----- 2 files changed, 48 insertions(+), 6 deletions(-)
diff --git a/rust/helpers.c b/rust/helpers.c index 05694e3f8f70..e42f5b446f92 100644 --- a/rust/helpers.c +++ b/rust/helpers.c @@ -59,6 +59,22 @@ void rust_helper_spin_unlock(spinlock_t *lock) } EXPORT_SYMBOL_GPL(rust_helper_spin_unlock); +unsigned long rust_helper_spin_lock_irqsave(spinlock_t *lock) +{ + unsigned long flags; + + spin_lock_irqsave(lock, flags); + + return flags; +} +EXPORT_SYMBOL_GPL(rust_helper_spin_lock_irqsave); + +void rust_helper_spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) +{ + spin_unlock_irqrestore(lock, flags); +} +EXPORT_SYMBOL_GPL(rust_helper_spin_unlock_irqrestore); + refcount_t rust_helper_REFCOUNT_INIT(int n) { return (refcount_t)REFCOUNT_INIT(n); diff --git a/rust/kernel/sync/lock/spinlock.rs b/rust/kernel/sync/lock/spinlock.rs index a52d20fc9755..34dec09a97c0 100644 --- a/rust/kernel/sync/lock/spinlock.rs +++ b/rust/kernel/sync/lock/spinlock.rs @@ -61,6 +61,8 @@ macro_rules! new_spinlock { /// assert_eq!(e.c, 10); /// assert_eq!(e.d.lock().a, 20); /// assert_eq!(e.d.lock().b, 30); +/// assert_eq!(e.d.lock_irqsave().a, 20); +/// assert_eq!(e.d.lock_irqsave().b, 30); /// ``` /// /// The following example shows how to use interior mutability to modify the contents of a struct @@ -79,6 +81,12 @@ macro_rules! new_spinlock { /// guard.a += 10; /// guard.b += 20; /// } +/// +/// fn example2(m: &SpinLock<Example>) { +/// let mut guard = m.lock_irqsave(); +/// guard.a += 10; +/// guard.b += 20; +/// } /// ``` /// /// [`spinlock_t`]: ../../../../include/linux/spinlock.h @@ -90,7 +98,7 @@ pub struct SpinLockBackend; // SAFETY: The underlying kernel `spinlock_t` object ensures mutual exclusion. unsafe impl super::Backend for SpinLockBackend { type State = bindings::spinlock_t; - type GuardState = (); + type GuardState = Option<core::ffi::c_ulong>; unsafe fn init( ptr: *mut Self::State, @@ -105,12 +113,30 @@ unsafe impl super::Backend for SpinLockBackend { unsafe fn lock(ptr: *mut Self::State) -> Self::GuardState { // SAFETY: The safety requirements of this function ensure that `ptr` points to valid // memory, and that it has been initialised before. - unsafe { bindings::spin_lock(ptr) } + unsafe { bindings::spin_lock(ptr) }; + None } - unsafe fn unlock(ptr: *mut Self::State, _guard_state: &Self::GuardState) { - // SAFETY: The safety requirements of this function ensure that `ptr` is valid and that the - // caller is the owner of the mutex. - unsafe { bindings::spin_unlock(ptr) } + unsafe fn unlock(ptr: *mut Self::State, guard_state: &Self::GuardState) { + match guard_state { + // SAFETY: The safety requirements of this function ensure that `ptr` is valid and that + // the caller is the owner of the mutex. + Some(flags) => unsafe { bindings::spin_unlock_irqrestore(ptr, *flags) }, + // SAFETY: The safety requirements of this function ensure that `ptr` is valid and that + // the caller is the owner of the mutex. + None => unsafe { bindings::spin_unlock(ptr) }, + } + } +} + +// SAFETY: The underlying kernel `spinlock_t` object ensures mutual exclusion. We use the `irqsave` +// variant of the C lock acquisition functions to disable interrupts and retrieve the original +// interrupt state, and the `irqrestore` variant of the lock release functions to restore the state +// in `unlock` -- we use the guard context to determine which method was used to acquire the lock. +unsafe impl super::IrqSaveBackend for SpinLockBackend { + unsafe fn lock_irqsave(ptr: *mut Self::State) -> Self::GuardState { + // SAFETY: The safety requirements of this function ensure that `ptr` points to valid + // memory, and that it has been initialised before. + Some(unsafe { bindings::spin_lock_irqsave(ptr) }) } } -- 2.34.1
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