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For this purpose, add > a Rust wrapper around `struct ratelimit_state` and use it in the new > macros. > > Tested-by: Alvin Sun > Reviewed-by: Carlos Llamas > Link: https://github.com/Rust-for-Linux/linux/issues/122 > Signed-off-by: Alice Ryhl > --- > rust/helpers/helpers.c | 1 + > rust/helpers/ratelimit.c | 14 +++ > rust/kernel/lib.rs | 1 + > rust/kernel/prelude.rs | 8 ++ > rust/kernel/ratelimit.rs | 215 ++++++++++++++++++++++++++++++++= ++++++ > rust/kernel/sync/lock/spinlock.rs | 1 - > 6 files changed, 239 insertions(+), 1 deletion(-) > > diff --git a/rust/kernel/ratelimit.rs b/rust/kernel/ratelimit.rs > new file mode 100644 > index 000000000000..426992e452a2 > --- /dev/null > +++ b/rust/kernel/ratelimit.rs > @@ -0,0 +1,215 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +//! Rate limiting support. > +//! > +//! C header: [`include/linux/ratelimit.h`](srctree/include/linux/rateli= mit.h) > + > +use crate::{ > + bindings, > + prelude::*, > + types::Opaque, // > +}; > + > +/// Defines a `static` containing a [`Ratelimit`]. > +#[macro_export] > +macro_rules! ratelimit_state_init { > + ($name:ident, $interval:expr, $burst:expr $(,)?) =3D> { > + static $name: $crate::ratelimit::Ratelimit =3D { > + let name =3D $crate::c_str!(::core::stringify!($name)); > + let interval =3D $interval; > + let burst =3D $burst; > + // SAFETY: This will be stored in static memory. > + unsafe { $crate::ratelimit::Ratelimit::new_static(name, inte= rval, burst) } > + }; > + }; > +} > +pub use ratelimit_state_init; > + > +/// Rate limiter state. > +/// > +/// # Invariants > +/// > +/// The `inner` field contains an initialized `struct ratelimit_state`. > +#[pin_data(PinnedDrop)] > +#[repr(transparent)] > +pub struct Ratelimit { > + #[pin] > + inner: Opaque, > +} > + > +// SAFETY: `Ratelimit` is safe to be sent to any task. > +unsafe impl Send for Ratelimit {} > + > +// SAFETY: `Ratelimit` is safe to be accessed concurrently as it is prot= ected by an internal > +// spinlock. > +unsafe impl Sync for Ratelimit {} > + > +impl Ratelimit { > + /// Constructs a [`Ratelimit`] with the specified configuration. > + /// > + /// If `interval` is zero, then no rate limit is applied. > + #[inline] > + pub fn new(interval: i32, burst: i32) -> impl PinInit { > + // INVARIANT: This creates a `Ratelimit` containing an initializ= ed `struct ratelimit_state` > + pin_init!(Self { > + inner <- Opaque::ffi_init(|slot: *mut bindings::ratelimit_st= ate| { > + // SAFETY: `slot` is a valid pointer to an uninitialized= `struct ratelimit_state`. > + // The memory is pinned so it remains valid until `ratel= imit_state_exit` is called. > + unsafe { bindings::ratelimit_state_init(slot, interval, = burst) }; > + }), > + }) > + } > + > + /// Constructs a [`Ratelimit`] with the default configuration. > + #[inline] > + pub fn new_default() -> impl PinInit { > + Ratelimit::new(Ratelimit::DEFAULT_INTERVAL, Ratelimit::DEFAULT_B= URST) > + } > + > + /// Constructs a [`Ratelimit`] with the specified configuration. > + /// > + /// The name will be used for the lockdep name of the internal spinl= ock. See [`Self::new`] for > + /// the meaning of `interval` and `burst`. > + /// > + /// # Safety > + /// > + /// The resulting value must be stored in static memory. This one is const-only so shouldn't be code-generated. #[inline] Best, Gary > + pub const unsafe fn new_static(name: &'static CStr, interval: i32, b= urst: i32) -> Self { > + Self { > + inner: Opaque::new(bindings::ratelimit_state { > + lock: kernel::sync::lock::spinlock::raw_spin_lock_unlock= ed(name), > + interval, > + burst, > + ..pin_init::zeroed() > + }), > + } > + }