Similar to the typed encoding layer, add some decoding type machinery. Add a simple macro `nvkv_decode!` which implements `Schema` for a struct by composing visit calls to each member. Add some common `Schema` kinds, such as `Array` which collects an array value into a fixed maximum size array, and `Required` which fails a decode if the value is not sent.
Signed-off-by: Eliot Courtney <[email protected]> --- drivers/gpu/nova-core/gsp/nvkv.rs | 11 +- drivers/gpu/nova-core/gsp/nvkv/decode.rs | 622 ++++++++++++++++++++++++++++++- 2 files changed, 628 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/nova-core/gsp/nvkv.rs b/drivers/gpu/nova-core/gsp/nvkv.rs index 7ac3a459a98b..5791df07a7fa 100644 --- a/drivers/gpu/nova-core/gsp/nvkv.rs +++ b/drivers/gpu/nova-core/gsp/nvkv.rs @@ -9,7 +9,7 @@ //! function calls will map to some struct - for example, f(GPU_NAME_STRING_KEY, 0, b"some gpu") //! naturally maps to storing a &str with the GPU name. -#![expect(unused_imports)] +#![cfg_attr(not(CONFIG_KUNIT), expect(unused_imports))] #![cfg_attr(not(CONFIG_KUNIT), expect(unused_macros))] use core::{ @@ -23,7 +23,8 @@ use kernel::{ alloc::{ allocator::KVmalloc, - Allocator, // + Allocator, + ArrayVec, // }, bitfield, num::Bounded, @@ -148,6 +149,12 @@ fn default() -> Self { } } +/// A schema field for an array value under the NVKV key `KEY_ID`. +#[repr(transparent)] +pub(crate) struct Array<T: Default + Copy, const N: usize, const KEY_ID: KeyId> { + vec: ArrayVec<T, N>, +} + bitfield! { /// The op word that starts each NVKV operation. struct Op(u64) { diff --git a/drivers/gpu/nova-core/gsp/nvkv/decode.rs b/drivers/gpu/nova-core/gsp/nvkv/decode.rs index c4c24fe1108e..24dad31296cb 100644 --- a/drivers/gpu/nova-core/gsp/nvkv/decode.rs +++ b/drivers/gpu/nova-core/gsp/nvkv/decode.rs @@ -3,11 +3,22 @@ #![cfg_attr(not(CONFIG_KUNIT), expect(dead_code))] -use kernel::prelude::*; +use core::{ + convert::Infallible, + marker::PhantomData, // +}; + +use kernel::{ + alloc::ArrayVec, + prelude::*, // +}; +use pin_init::init_array_from_fn; use crate::{ gsp::nvkv::{ + Array, Index, + Key, KeyId, Op, Opcode, // @@ -15,6 +26,353 @@ num, // }; +/// Defines a schema struct together with its [`Schema`] and [`Visit`] implementations that decode +/// into `$target`. +/// +/// Each member of the struct should implement [`Schema`] and [`Visit`]. For every (key, index, +/// value) triple decoded from the NVKV stream, the generated parent `Visit` implementation will +/// call each member in declaration order with that triple. If a member consumes that triple, it +/// will stop there. Otherwise it will keep going until all members are tried. +/// +/// The schema struct holds the state required by the schema implementation to do the decode. It's +/// recommended to use one of the existing Schema kinds (`Required`, `Accumulated`, `Key`, `Array`, +/// `Indexed`) for each member. +/// +/// Use a lifetime on the schema struct if you want to borrow data directly from the encoded stream, +/// for example, `Key<&'d [u8], KEY>`. +/// +/// # Examples +/// +/// ``` +/// nvkv_decode! { +/// struct RequestSchema => Request { +/// id: Required<u32, 0x0001>, +/// name: Array<u8, 64, 0x0002>, +/// } +/// } +/// +/// nvkv_decode! { +/// struct NameSchema<'d> => Name<'d> { +/// name: Key<&'d [u8], 0x0002>, +/// } +/// } +/// ``` +macro_rules! nvkv_decode { + // A schema which doesn't borrow from the stream. The macro uses a generic lifetime for the + // [`Visit`] implementation but not for the struct itself. This allows omitting the unused + // lifetime on the struct. + ( + $(#[$attr:meta])* + $vis:vis struct $name:ident => $target:ty { $($fields:tt)* } + ) => { + nvkv_decode!( + @impl ['data] [] $(#[$attr])* $vis struct $name => $target { $($fields)* } + ); + }; + // A schema which borrows from the stream for lifetime `$datalt`. The macro connects the + // [`Visit`] lifetime with the struct lifetime. + ( + $(#[$attr:meta])* + $vis:vis struct $name:ident<$datalt:lifetime> => $target:ty { $($fields:tt)* } + ) => { + nvkv_decode!( + @impl [$datalt] [<$datalt>] $(#[$attr])* $vis struct $name => $target { $($fields)* } + ); + }; + (@impl [$datalt:lifetime] [$($generics:tt)*] + $(#[$attr:meta])* + $vis:vis struct $name:ident => $target:ty { + $( + $(#[$field_attr:meta])* + $field_vis:vis $field:ident : $ty:ty + ),* $(,)? + } + ) => { + $(#[$attr])* + $vis struct $name $($generics)* { + $( + $(#[$field_attr])* + $field_vis $field: $ty, + )* + } + + impl $($generics)* $crate::gsp::nvkv::Schema for $name $($generics)* { + type Target = $target; + + #[inline] + fn init() -> impl ::kernel::prelude::Init<Self> { + ::pin_init::init!(Self { + $( $field <- <$ty as $crate::gsp::nvkv::Schema>::init(), )* + }) + } + + #[inline] + fn finish( + &mut self, + ) -> impl ::kernel::prelude::Init<Self::Target, ::kernel::error::Error> + '_ { + let Self { $($field,)* } = self; + ::kernel::try_init!(Self::Target { + $( $field <- $crate::gsp::nvkv::Schema::finish($field), )* + }? ::kernel::error::Error) + } + } + + impl<$datalt> $crate::gsp::nvkv::Visit<$datalt> for $name $($generics)* { + fn visit( + &mut self, + key: $crate::gsp::nvkv::KeyId, + index: $crate::gsp::nvkv::Index, + value: $crate::gsp::nvkv::DecoderValue<$datalt>, + ) -> ::kernel::error::Result<bool> { + // TODO: This performs worst-case O(#fields) visit calls. Consider optimising this + // if it becomes a problem. + Ok(false + $( || $crate::gsp::nvkv::Visit::visit(&mut self.$field, key, index, value)? )*) + } + } + }; +} + +impl<T: Default, const KEY_ID: KeyId> Schema for Key<T, KEY_ID> { + type Target = T; + + #[inline] + fn init() -> impl Init<Self> { + Self::default() + } + + #[inline] + fn finish(&mut self) -> impl Init<Self::Target, Error> + '_ { + Ok(core::mem::take(&mut self.0)) + } +} + +impl<'data, T: TryFrom<DecoderValue<'data>, Error = Error>, const KEY_ID: KeyId> Visit<'data> + for Key<T, KEY_ID> +{ + #[inline] + fn visit(&mut self, key: KeyId, index: Index, value: DecoderValue<'data>) -> Result<bool> { + if key != KEY_ID { + Ok(false) + } else if index != Index::new::<0>() { + // Single values being set must be at index 0. + Err(EINVAL) + } else { + // Overwrite and take the latest value here. + self.0 = value.try_into()?; + Ok(true) + } + } +} + +impl<T: Default + Copy, const N: usize, const KEY_ID: KeyId> Schema for Array<T, N, KEY_ID> { + type Target = ArrayVec<T, N>; + + #[inline] + fn init() -> impl Init<Self> { + init!(Self { + vec <- ArrayVec::init_with::<Infallible>(|_| Ok(())), + }) + } + + #[inline] + fn finish(&mut self) -> impl Init<Self::Target, Error> + '_ { + ArrayVec::init_with(move |dst| { + dst.extend_from_slice(&self.vec)?; + self.vec.clear(); + Ok(()) + }) + } +} + +impl<'data, T: Default + Copy + 'data, const N: usize, const KEY_ID: KeyId> Visit<'data> + for Array<T, N, KEY_ID> +where + &'data [T]: TryFrom<DecoderValue<'data>, Error = Error>, +{ + fn visit(&mut self, key: KeyId, index: Index, value: DecoderValue<'data>) -> Result<bool> { + if key != KEY_ID { + return Ok(false); + } + // Require to be at index 0 + if index != Index::new::<0>() { + return Err(EINVAL); + } + // Reject oversized and take the latest value. + self.vec.clear(); + self.vec.extend_from_slice(value.try_into()?)?; + Ok(true) + } +} + +/// A schema field for a key that must be present. +/// +/// `finish` fails with `EINVAL` if no value arrived for the key. +#[repr(transparent)] +pub(crate) struct Required<T, const KEY_ID: KeyId>(Key<Option<T>, KEY_ID>); + +impl<T, const KEY_ID: KeyId> Schema for Required<T, KEY_ID> { + type Target = T; + + #[inline] + fn init() -> impl Init<Self> { + Self(None.into()) + } + + #[inline] + fn finish(&mut self) -> impl Init<Self::Target, Error> + '_ { + (self.0).0.take().ok_or(EINVAL) + } +} + +impl<'data, T: TryFrom<DecoderValue<'data>, Error = Error>, const KEY_ID: KeyId> Visit<'data> + for Required<T, KEY_ID> +{ + #[inline] + fn visit(&mut self, key: KeyId, index: Index, value: DecoderValue<'data>) -> Result<bool> { + self.0.visit(key, index, value) + } +} + +/// Expects objects specified sequentially with index starting from zero. +/// +/// This stores two `Schema`s which are initially empty. A `Schema` is expected to be complete when +/// we get the next index. +pub(crate) struct Accumulated<S: Schema> { + // Tracks the current index (starting from 0). When this advances, the schema `current` must be + // finished. + current_index: Index, + + // The current `Schema` being constructed now. + current: S, + + // Tracks empty schemas (one that has never consumed a key via `visit`), so we don't call + // `finish` on them. + current_started: bool, + + // The next `Schema` to be constructed. This is required because we must consume a key intended + // for this Schema from the next index to know we can try calling `finish` on `current`. + next: S, + + // The set of results generated by the completed schemas so far. + accumulated: KVVec<S::Target>, +} + +impl<S: Schema> Schema for Accumulated<S> { + type Target = KVVec<S::Target>; + + #[inline] + fn init() -> impl Init<Self> { + init!(Self { + current_index: Index::new::<0>(), + current <- S::init(), + current_started: false, + next <- S::init(), + accumulated: KVVec::new(), + }) + } + + #[inline] + fn finish(&mut self) -> impl Init<Self::Target, Error> + '_ { + if self.current_started { + self.accumulated + .try_push_init(self.current.finish(), GFP_KERNEL)?; + self.current_started = false; + } + self.current_index = Index::new::<0>(); + Ok(core::mem::take(&mut self.accumulated)) + } +} + +impl<'data, S: Schema + Visit<'data>> Visit<'data> for Accumulated<S> { + fn visit(&mut self, key: KeyId, index: Index, value: DecoderValue<'data>) -> Result<bool> { + if index != self.current_index { + if !self.next.visit(key, Index::new::<0>(), value)? { + // Unrelated key to us. + return Ok(false); + } + + // Require that objects at index k have all their keys sent before the k + 1 th object + // can be completed. Require that objects are sent contiguously in order from index 0. + if !self.current_started || index != self.current_index + 1 { + return Err(EINVAL); + } + + // The current value must be finished. Push it and swap in `next`. + self.accumulated + .try_push_init(self.current.finish(), GFP_KERNEL)?; + core::mem::swap(&mut self.current, &mut self.next); + self.current_started = true; + self.current_index = index; + Ok(true) + } else { + let consumed = self.current.visit(key, Index::new::<0>(), value)?; + self.current_started |= consumed; + Ok(consumed) + } + } +} + +/// A schema field that scatters indexed values into an array of `N` slots. +/// +/// Values are decoded from the encoded stream using the type `As`, but then converted into `T` with +/// [`From`], like the `As` parameter of [`Key`]. +#[repr(transparent)] +pub(crate) struct Indexed<T, const N: usize, const KEY_ID: KeyId, As = T> { + slots: [T; N], + _as: PhantomData<As>, +} + +/// Copies `elems`, converted to `T`, into `slots` at `start`. +/// +/// Fails with `EINVAL` if the window does not fit in `slots`. +fn scatter_window<T: From<As>, As: Copy>(slots: &mut [T], start: usize, elems: &[As]) -> Result { + let end = start.checked_add(elems.len()).ok_or(EINVAL)?; + // Reject indices outside of the declared array size. + let dst = slots.get_mut(start..end).ok_or(EINVAL)?; + for (d, &e) in dst.iter_mut().zip(elems) { + *d = T::from(e); + } + Ok(()) +} + +impl<T: Default, const N: usize, const KEY_ID: KeyId, As> Schema for Indexed<T, N, KEY_ID, As> { + type Target = [T; N]; + + #[inline] + fn init() -> impl Init<Self> { + init!(Self { + slots <- init_array_from_fn(|_| T::default()), + _as: PhantomData, + }) + } + + #[inline] + fn finish(&mut self) -> impl Init<Self::Target, Error> + '_ { + init_array_from_fn(|i| Ok::<_, Error>(core::mem::take(&mut self.slots[i]))) + } +} + +impl<'data, T, const N: usize, const KEY_ID: KeyId, As> Visit<'data> for Indexed<T, N, KEY_ID, As> +where + T: From<As>, + As: Copy + TryFrom<DecoderValue<'data>, Error = Error> + 'data, + &'data [As]: TryFrom<DecoderValue<'data>, Error = Error>, +{ + fn visit(&mut self, key: KeyId, index: Index, value: DecoderValue<'data>) -> Result<bool> { + if key != KEY_ID { + return Ok(false); + } + let start = index.cast::<usize>().get(); + // Accept both scalar vs scattered array setting for flexibility. + match <&[As]>::try_from(value) { + Ok(elems) => scatter_window(&mut self.slots, start, elems)?, + Err(_) => scatter_window(&mut self.slots, start, &[As::try_from(value)?])?, + } + Ok(true) + } +} + /// A decoded NVKV value. #[derive(Copy, Clone, Debug, PartialEq, Eq)] pub(crate) enum DecoderValue<'a> { @@ -51,7 +409,16 @@ fn try_from(value: DecoderValue<'a>) -> Result<Self> { impl_try_from_decoder_value!(&'a [u32], Array32); impl_try_from_decoder_value!(&'a [u64], Array64); -/// A visitor that consumes decoded NVKV and produces a `Target`. +/// Lets `Key<Option<T>, KEY_ID>` accept whatever `Key<T, KEY_ID>` accepts. +impl<'a, T: TryFrom<DecoderValue<'a>, Error = Error>> TryFrom<DecoderValue<'a>> for Option<T> { + type Error = Error; + + fn try_from(value: DecoderValue<'a>) -> Result<Self> { + T::try_from(value).map(Some) + } +} + +/// The state of one NVKV decode operation which produces a target value `Target`. pub(crate) trait Schema { type Target; @@ -65,7 +432,12 @@ fn init() -> impl Init<Self> /// Returns an initializer that makes the decoded `Target`. /// - /// After the returned initializer runs, the schema should be empty again. + /// After the returned initializer runs successfully, the schema must be empty again. For + /// example, this is required by [`Accumulated`] which finishes one object and then decodes the + /// next one with the same schema. Implementations generated by `nvkv_decode!` meet this + /// requirement. If the initializer fails, the `Schema` can be in a valid but non-fresh state. + /// Taking `self` instead of `&mut self` would avoid this contract, but it forces a copy of the + /// schema onto the stack. fn finish(&mut self) -> impl Init<Self::Target, Error> + '_; } @@ -295,6 +667,133 @@ fn visit(&mut self, key: KeyId, index: Index, value: DecoderValue<'d>) -> Result Ok(()) } + // Tests that decoding via the `nvkv_decode!` macro works correctly. + #[test] + fn decode_typed_struct() -> Result { + const SCALAR32_KEY: KeyId = 0x1234; + const SCALAR64_KEY: KeyId = 0x1235; + const ARRAY8_KEY: KeyId = 0x1236; + const ARRAY32_KEY: KeyId = 0x1237; + const ARRAY64_KEY: KeyId = 0x1238; + const OPT_PRESENT_KEY: KeyId = 0x1239; + const OPT_ABSENT_KEY: KeyId = 0x123a; + const X_KEY: KeyId = 0x0100; + const Y_KEY: KeyId = 0x0101; + const SLOT_KEY: KeyId = 0x0200; + + const SCALAR32_VALUE: u32 = 0x89ab_cdef; + const SCALAR64_VALUE: u64 = 0x0123_4567_89ab_cdef; + const ARRAY8_VALUE: &[u8] = &[0x12, 0x34, 0x56]; + const ARRAY32_VALUE: &[u32] = &[0x0123_4567, 0x89ab_cdef]; + const ARRAY64_VALUE: &[u64] = &[0x0123_4567_89ab_cdef, 0xfedc_ba98_7654_3210]; + const OPT_PRESENT_VALUE: u32 = 0x55; + + nvkv_decode! { + struct PairSchema => Pair { + x: Required<u32, X_KEY>, + y: Required<u32, Y_KEY>, + } + } + + struct Pair { + x: u32, + y: u32, + } + + nvkv_decode! { + struct TestSchema => TestDecodeable { + scalar32: Required<u32, SCALAR32_KEY>, + scalar64: Required<u64, SCALAR64_KEY>, + array8: Array<u8, 64, ARRAY8_KEY>, + array32: Array<u32, 64, ARRAY32_KEY>, + array64: Array<u64, 32, ARRAY64_KEY>, + opt_present: Key<Option<u32>, OPT_PRESENT_KEY>, + opt_absent: Key<Option<u32>, OPT_ABSENT_KEY>, + pairs: Accumulated<PairSchema>, + slots: Indexed<u32, 4, SLOT_KEY>, + } + } + + struct TestDecodeable { + scalar32: u32, + scalar64: u64, + array8: ArrayVec<u8, 64>, + array32: ArrayVec<u32, 64>, + array64: ArrayVec<u64, 32>, + opt_present: Option<u32>, + opt_absent: Option<u32>, + pairs: KVVec<Pair>, + slots: [u32; 4], + } + + let index0 = Index::new::<0>(); + let index1 = Index::new::<1>(); + let index2 = Index::new::<2>(); + let mut encoder = Encoder::new(); + encoder.encode_u32(SCALAR32_KEY, index0, SCALAR32_VALUE)?; + encoder.encode_u64(SCALAR64_KEY, index0, SCALAR64_VALUE)?; + encoder.encode_array8(ARRAY8_KEY, index0, ARRAY8_VALUE)?; + encoder.encode_array32(ARRAY32_KEY, index0, ARRAY32_VALUE)?; + encoder.encode_array64(ARRAY64_KEY, index0, ARRAY64_VALUE)?; + encoder.encode_u32(OPT_PRESENT_KEY, index0, OPT_PRESENT_VALUE)?; + encoder.encode_u32(X_KEY, index0, 1)?; + encoder.encode_u32(Y_KEY, index0, 2)?; + encoder.encode_u32(SLOT_KEY, index1, 20)?; + encoder.encode_u32(X_KEY, index1, 3)?; + encoder.encode_u32(Y_KEY, index1, 4)?; + encoder.encode_u32(SLOT_KEY, index0, 10)?; + encoder.encode_array32(SLOT_KEY, index2, &[30, 40])?; + let serialized = encoder.finish(); + + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(TestSchema::init(), GFP_KERNEL)?; + let decoded = KBox::try_init(decoder.decode(&mut *schema)?, GFP_KERNEL)?; + + assert_eq!(decoded.scalar32, SCALAR32_VALUE); + assert_eq!(decoded.scalar64, SCALAR64_VALUE); + assert_eq!(*decoded.array8, *ARRAY8_VALUE); + assert_eq!(*decoded.array32, *ARRAY32_VALUE); + assert_eq!(*decoded.array64, *ARRAY64_VALUE); + assert_eq!(decoded.opt_present, Some(OPT_PRESENT_VALUE)); + assert_eq!(decoded.opt_absent, None); + assert_eq!(decoded.pairs.len(), 2); + assert_eq!(decoded.pairs[0].x, 1); + assert_eq!(decoded.pairs[0].y, 2); + assert_eq!(decoded.pairs[1].x, 3); + assert_eq!(decoded.pairs[1].y, 4); + assert_eq!(decoded.slots, [10, 20, 30, 40]); + + Ok(()) + } + + // Tests that a schema too large for the stack decodes on the heap. + #[test] + fn decode_large_schema_on_heap() -> Result { + const BLOB_KEY: KeyId = 0x1400; + const BLOB_VALUE: &[u8] = &[0xab; 100]; + + nvkv_decode! { + struct BigSchema => BigDecodeable { + blob: Array<u8, 2048, BLOB_KEY>, + } + } + + struct BigDecodeable { + blob: ArrayVec<u8, 2048>, + } + + let mut encoder = Encoder::new(); + encoder.encode_array8(BLOB_KEY, Index::new::<0>(), BLOB_VALUE)?; + let serialized = encoder.finish(); + + let mut schema = KBox::init(BigSchema::init(), GFP_KERNEL)?; + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let decoded = KBox::try_init(decoder.decode(&mut *schema)?, GFP_KERNEL)?; + + assert_eq!(*decoded.blob, *BLOB_VALUE); + Ok(()) + } + /// Records each visit as (key, index, value), for tests on hand-built streams. #[derive(Default)] struct Recorder<'d> { @@ -484,4 +983,121 @@ fn decode_raw_words_malformed() -> Result { Ok(()) } + + // Tests the error paths of the schema kinds. + #[test] + fn decode_typed_struct_errors() -> Result { + const VALUE_KEY: KeyId = 0x2200; + const SLOT_KEY: KeyId = 0x2201; + const BLOB_KEY: KeyId = 0x2202; + const X_KEY: KeyId = 0x2203; + const Y_KEY: KeyId = 0x2204; + + let index0 = Index::new::<0>(); + let index1 = Index::new::<1>(); + let index2 = Index::new::<2>(); + + nvkv_decode! { + struct ValueSchema => Value { + value: Key<u32, VALUE_KEY>, + } + } + + struct Value { + value: u32, + } + + // A single value at a non-zero index. + let mut encoder = Encoder::new(); + encoder.encode_u32(VALUE_KEY, index1, 1)?; + let serialized = encoder.finish(); + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(ValueSchema::init(), GFP_KERNEL)?; + assert!(decoder.decode(&mut *schema).is_err()); + + // A 64-bit value for a 32-bit key. + let mut encoder = Encoder::new(); + encoder.encode_u64(VALUE_KEY, index0, 1)?; + let serialized = encoder.finish(); + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(ValueSchema::init(), GFP_KERNEL)?; + assert!(decoder.decode(&mut *schema).is_err()); + + nvkv_decode! { + struct SlotsSchema => Slots { + slots: Indexed<u32, 2, SLOT_KEY>, + } + } + + struct Slots { + slots: [u32; 2], + } + + // An index past the declared slots. + let mut encoder = Encoder::new(); + encoder.encode_u32(SLOT_KEY, index2, 1)?; + let serialized = encoder.finish(); + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(SlotsSchema::init(), GFP_KERNEL)?; + assert!(decoder.decode(&mut *schema).is_err()); + + nvkv_decode! { + struct BlobSchema => Blob { + blob: Array<u8, 4, BLOB_KEY>, + } + } + + struct Blob { + blob: ArrayVec<u8, 4>, + } + + // An array longer than the declared capacity. + let mut encoder = Encoder::new(); + encoder.encode_array8(BLOB_KEY, index0, &[0; 5])?; + let serialized = encoder.finish(); + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(BlobSchema::init(), GFP_KERNEL)?; + assert!(decoder.decode(&mut *schema).is_err()); + + nvkv_decode! { + struct PairSchema => Pair { + x: Required<u32, X_KEY>, + y: Required<u32, Y_KEY>, + } + } + + struct Pair { + x: u32, + y: u32, + } + + nvkv_decode! { + struct PairsSchema => Pairs { + pairs: Accumulated<PairSchema>, + } + } + + struct Pairs { + pairs: KVVec<Pair>, + } + + // Accumulated objects must start at index 0. + let mut encoder = Encoder::new(); + encoder.encode_u32(X_KEY, index1, 1)?; + let serialized = encoder.finish(); + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(PairsSchema::init(), GFP_KERNEL)?; + assert!(decoder.decode(&mut *schema).is_err()); + + // Accumulated objects must be complete before the next one starts. + let mut encoder = Encoder::new(); + encoder.encode_u32(X_KEY, index0, 1)?; + encoder.encode_u32(X_KEY, index1, 2)?; + let serialized = encoder.finish(); + let decoder = Decoder::new(&serialized, UnknownKeyPolicy::Error); + let mut schema = KBox::init(PairsSchema::init(), GFP_KERNEL)?; + assert!(decoder.decode(&mut *schema).is_err()); + + Ok(()) + } } -- 2.55.0
