linux-toradex.git/rust/kernel/error.rs, branch v6.4-rc1

rust: error: Add from_result() helper

2023-04-12T16:41:04+00:00

Add a helper function to easily return C result codes from a Rust function
that calls functions which return a Result.

Lina: Imported from rust-for-linux/rust, originally developed by Wedson
as part of file_operations.rs. Added the allow() flags since there is no
user in the kernel crate yet and fixed a typo in a comment. Replaced the
macro with a function taking a closure, per discussion on the ML.

Co-developed-by: Fox Chen 
Signed-off-by: Fox Chen 
Co-developed-by: Miguel Ojeda 
Signed-off-by: Miguel Ojeda 
Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Asahi Lina 
Link: https://lore.kernel.org/r/20230224-rust-error-v3-6-03779bddc02b@asahilina.net
Signed-off-by: Miguel Ojeda

rust: error: Add a helper to convert a C ERR_PTR to a `Result`

2023-04-12T16:41:04+00:00

Some kernel C API functions return a pointer which embeds an optional
`errno`. Callers are supposed to check the returned pointer with
`IS_ERR()` and if this returns `true`, retrieve the `errno` using
`PTR_ERR()`.

Create a Rust helper function to implement the Rust equivalent:
transform a `*mut T` to `Result<*mut T>`.

Lina: Imported from rust-for-linux/linux, with subsequent refactoring
and contributions squashed in and attributed below. Renamed the function
to from_err_ptr().

Co-developed-by: Boqun Feng 
Signed-off-by: Boqun Feng 
Co-developed-by: Miguel Ojeda 
Signed-off-by: Miguel Ojeda 
Co-developed-by: Fox Chen 
Signed-off-by: Fox Chen 
Co-developed-by: Gary Guo 
Signed-off-by: Gary Guo 
Signed-off-by: Sven Van Asbroeck 
Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Asahi Lina 
Link: https://lore.kernel.org/r/20230224-rust-error-v3-5-03779bddc02b@asahilina.net
[ Add a removal of `#[allow(dead_code)]`. ]
Signed-off-by: Miguel Ojeda

rust: error: Add to_result() helper

2023-04-12T16:41:04+00:00

Add a to_result() helper to convert kernel C return values to a Rust
Result, mapping >=0 values to Ok(()) and negative values to Err(...),
with Error::from_errno() ensuring that the errno is within range.

Lina: Imported from rust-for-linux/rust, originally developed by Wedson
as part of the AMBA device driver support.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Gary Guo 
Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Asahi Lina 
Link: https://lore.kernel.org/r/20230224-rust-error-v3-4-03779bddc02b@asahilina.net
[ Add a removal of `#[allow(dead_code)]`. ]
Signed-off-by: Miguel Ojeda

rust: error: Add Error::from_errno{_unchecked}()

2023-04-12T16:41:04+00:00

Add a function to create `Error` values out of a kernel error return,
which safely upholds the invariant that the error code is well-formed
(negative and greater than -MAX_ERRNO). If a malformed code is passed
in, it will be converted to EINVAL.

Lina: Imported from rust-for-linux/rust as authored by Miguel and Fox
with refactoring from Wedson, renamed from_kernel_errno() to
from_errno().

Co-developed-by: Fox Chen 
Signed-off-by: Fox Chen 
Co-developed-by: Wedson Almeida Filho 
Signed-off-by: Wedson Almeida Filho 
Signed-off-by: Miguel Ojeda 
Reviewed-by: Andreas Hindborg 
Reviewed-by: Gary Guo 
Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Asahi Lina 
Link: https://lore.kernel.org/r/20230224-rust-error-v3-3-03779bddc02b@asahilina.net
[ Mark the new associated functions as `#[allow(dead_code)]`. ]
Signed-off-by: Miguel Ojeda

rust: error: Add Error::to_ptr()

2023-04-12T16:41:04+00:00

This is the Rust equivalent to ERR_PTR(), for use in C callbacks.
Marked as #[allow(dead_code)] for now, since it does not have any
consumers yet.

Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Asahi Lina 
Reviewed-by: Gary Guo 
Link: https://lore.kernel.org/r/20230224-rust-error-v3-2-03779bddc02b@asahilina.net
Signed-off-by: Miguel Ojeda

rust: error: Rename to_kernel_errno() -> to_errno()

2023-04-12T16:41:04+00:00

This is kernel code, so specifying "kernel" is redundant. Let's simplify
things and just call it to_errno().

Reviewed-by: Gary Guo 
Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Asahi Lina 
Link: https://lore.kernel.org/r/20230224-rust-error-v3-1-03779bddc02b@asahilina.net
Signed-off-by: Miguel Ojeda

rust: error: add `From` implementations for `Error`

2022-12-04T00:59:15+00:00

Add a set of `From` implementations for the `Error` kernel type.

These implementations allow to easily convert from standard Rust
error types to the usual kernel errors based on one of the `E*`
integer codes.

On top of that, the question mark Rust operator (`?`) implicitly
performs a conversion on the error value using the `From` trait
when propagating. Thus it is extra convenient to use.

For instance, a kernel function that needs to convert a `i64` into
a `i32` and to bubble up the error as a kernel error may write:

    fn f(x: i64) -> Result<...> {
        ...
        let y = i32::try_from(x)?;
        ...
    }

which will transform the `TryFromIntError` into an `Err(EINVAL)`.

Co-developed-by: Adam Bratschi-Kaye 
Signed-off-by: Adam Bratschi-Kaye 
Co-developed-by: Nándor István Krácser 
Signed-off-by: Nándor István Krácser 
Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Finn Behrens 
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda

rust: error: add codes from `errno-base.h`

2022-12-04T00:59:15+00:00

Only a few codes were added so far. With the `declare_err!`
macro in place, add the remaining ones (which is most of them)
from `include/uapi/asm-generic/errno-base.h`.

Co-developed-by: Wedson Almeida Filho 
Signed-off-by: Wedson Almeida Filho 
Signed-off-by: Viktor Garske 
Reviewed-by: Gary Guo 
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda

rust: error: declare errors using macro

2022-12-04T00:59:15+00:00

Add a macro to declare errors, which simplifies the work needed to
add each one, avoids repetition of the code and makes it easier to
change the way they are declared.

Signed-off-by: Finn Behrens 
Reviewed-by: Gary Guo 
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda

rust: add `kernel` crate

2022-09-28T06:58:24+00:00

The `kernel` crate currently includes all the abstractions that wrap
kernel features written in C.

These abstractions call the C side of the kernel via the generated
bindings with the `bindgen` tool. Modules developed in Rust should
never call the bindings themselves.

In the future, as the abstractions grow in number, we may need
to split this crate into several, possibly following a similar
subdivision in subsystems as the kernel itself and/or moving
the code to the actual subsystems.

Reviewed-by: Greg Kroah-Hartman 
Co-developed-by: Alex Gaynor 
Signed-off-by: Alex Gaynor 
Co-developed-by: Geoffrey Thomas 
Signed-off-by: Geoffrey Thomas 
Co-developed-by: Finn Behrens 
Signed-off-by: Finn Behrens 
Co-developed-by: Adam Bratschi-Kaye 
Signed-off-by: Adam Bratschi-Kaye 
Co-developed-by: Sven Van Asbroeck 
Signed-off-by: Sven Van Asbroeck 
Co-developed-by: Gary Guo 
Signed-off-by: Gary Guo 
Co-developed-by: Boris-Chengbiao Zhou 
Signed-off-by: Boris-Chengbiao Zhou 
Co-developed-by: Boqun Feng 
Signed-off-by: Boqun Feng 
Co-developed-by: Fox Chen 
Signed-off-by: Fox Chen 
Co-developed-by: Viktor Garske 
Signed-off-by: Viktor Garske 
Co-developed-by: Dariusz Sosnowski 
Signed-off-by: Dariusz Sosnowski 
Co-developed-by: Léo Lanteri Thauvin 
Signed-off-by: Léo Lanteri Thauvin 
Co-developed-by: Niklas Mohrin 
Signed-off-by: Niklas Mohrin 
Co-developed-by: Milan Landaverde 
Signed-off-by: Milan Landaverde 
Co-developed-by: Morgan Bartlett 
Signed-off-by: Morgan Bartlett 
Co-developed-by: Maciej Falkowski 
Signed-off-by: Maciej Falkowski 
Co-developed-by: Nándor István Krácser 
Signed-off-by: Nándor István Krácser 
Co-developed-by: David Gow 
Signed-off-by: David Gow 
Co-developed-by: John Baublitz 
Signed-off-by: John Baublitz 
Co-developed-by: Björn Roy Baron 
Signed-off-by: Björn Roy Baron 
Signed-off-by: Wedson Almeida Filho 
Co-developed-by: Miguel Ojeda 
Signed-off-by: Miguel Ojeda