linux/rust
Gary Guo 38c3cbf507 rust: ptr: add panicking index projection variant
There have been a few cases where the programmer knows that the indices are
in bounds but the compiler cannot deduce that. This is also
compiler-version-dependent, so using build indexing here can be
problematic. On the other hand, it is also not ideal to use the fallible
variant, as it adds an error handling path that is never hit.

Add a new panicking index projection for this scenario. Like all panicking
operations, this should be used carefully only in cases where the user
knows the index is going to be in bounds, and panicking would indicate
something is catastrophically wrong.

To signify this, require users to explicitly denote the type of index being
used. The existing two types of index projections also gain the keyworded
version, which will be the recommended way going forward.

The keyworded syntax also paves the way of perhaps adding more flavors in
the future, e.g. `unsafe` index projection. However, unless the code is
extremely performance sensitive and bounds checking cannot be tolerated,
the panicking variant is safer and should be preferred, so it will be left
to the future when demand arises.

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260602-projection-syntax-rework-v2-3-6989470f5440@garyguo.net
[ Fixed broken intra-doc link. Added a few extra intra-doc links. Reworded
  some docs slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-06-05 10:16:11 +02:00
..
bindings drm for v7.1-rc1 2026-04-15 08:45:00 -07:00
helpers drm for v7.1-rc1 2026-04-15 08:45:00 -07:00
kernel rust: ptr: add panicking index projection variant 2026-06-05 10:16:11 +02:00
macros rust: macros: simplify code using feature(extract_if) 2026-04-07 10:00:24 +02:00
pin-init rust: pin-init: fix incorrect accessor reference lifetime 2026-04-30 22:43:32 +02:00
proc-macro2 rust: proc-macro2: rebuild if the version text changes 2026-01-23 10:44:27 +01:00
quote rust: quote: add README.md 2025-11-24 17:15:43 +01:00
syn rust: syn: add README.md 2025-11-24 17:15:47 +01:00
uapi rust: declare cfi_encoding for lru_status 2026-04-07 10:00:25 +02:00
.gitignore
.kunitconfig rust: add kunitconfig 2025-03-19 23:22:21 +01:00
bindgen_parameters rust: declare cfi_encoding for lru_status 2026-04-07 10:00:25 +02:00
build_error.rs
compiler_builtins.rs ARM: 9441/1: rust: Enable Rust support for ARMv7 2025-03-26 13:31:16 +00:00
exports.c kbuild: rust: provide an option to inline C helpers into Rust 2026-03-30 02:03:52 +02:00
ffi.rs rust: replace CStr with core::ffi::CStr 2025-10-22 07:47:27 +02:00
Makefile rust: arch: um: Fix building 32-bit UML with GCC 2026-04-30 22:40:57 +02:00