Subject: [PATCH v3 02/12] rust: error: improve unsafe code in example

From: Valentin Obst <[email protected]>

The `from_err_ptr` function is safe. There is no need for the call to it
to be inside the unsafe block.

Reword the SAFETY comment to provide a better justification of why the
FFI call is safe.

Signed-off-by: Valentin Obst <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
---
rust/kernel/error.rs | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 4f0c1edd63b7..4786d3ee1e92 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -264,13 +264,9 @@ pub fn to_result(err: core::ffi::c_int) -> Result {
/// pdev: &mut PlatformDevice,
/// index: u32,
/// ) -> Result<*mut core::ffi::c_void> {
-/// // SAFETY: FFI call.
-/// unsafe {
-/// from_err_ptr(bindings::devm_platform_ioremap_resource(
-/// pdev.to_ptr(),
-/// index,
-/// ))
-/// }
+/// // SAFETY: `pdev` points to a valid platform device. There are no safety requirements
+/// // on `index`.
+/// from_err_ptr(unsafe { bindings::devm_platform_ioremap_resource(pdev.to_ptr(), index) })
/// }
/// ```
// TODO: Remove `dead_code` marker once an in-kernel client is available.

--
2.43.0



2024-02-01 02:24:26

by Trevor Gross

[permalink] [raw]
Subject: Re: [PATCH v3 02/12] rust: error: improve unsafe code in example

On Wed, Jan 31, 2024 at 3:24 PM Valentin Obst via B4 Relay
<[email protected]> wrote:
>
> From: Valentin Obst <[email protected]>
>
> The `from_err_ptr` function is safe. There is no need for the call to it
> to be inside the unsafe block.
>
> Reword the SAFETY comment to provide a better justification of why the
> FFI call is safe.
>
> Signed-off-by: Valentin Obst <[email protected]>
> Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
> Reviewed-by: Alice Ryhl <[email protected]>

Reviewed-by: Trevor Gross <[email protected]>

> ---
> rust/kernel/error.rs | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> index 4f0c1edd63b7..4786d3ee1e92 100644
> --- a/rust/kernel/error.rs
> +++ b/rust/kernel/error.rs
> @@ -264,13 +264,9 @@ pub fn to_result(err: core::ffi::c_int) -> Result {
> /// pdev: &mut PlatformDevice,
> /// index: u32,
> /// ) -> Result<*mut core::ffi::c_void> {
> -/// // SAFETY: FFI call.
> -/// unsafe {
> -/// from_err_ptr(bindings::devm_platform_ioremap_resource(
> -/// pdev.to_ptr(),
> -/// index,
> -/// ))
> -/// }
> +/// // SAFETY: `pdev` points to a valid platform device. There are no safety requirements
> +/// // on `index`.
> +/// from_err_ptr(unsafe { bindings::devm_platform_ioremap_resource(pdev.to_ptr(), index) })
> /// }
> /// ```
> // TODO: Remove `dead_code` marker once an in-kernel client is available.
>
> --
> 2.43.0
>
>