rust: error: Add a helper to convert a C ERR_PTR to a `Result`
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 <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Co-developed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
Co-developed-by: Fox Chen <[email protected]>
Signed-off-by: Fox Chen <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Signed-off-by: Sven Van Asbroeck <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Asahi Lina <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Add a removal of `#[allow(dead_code)]`. ]
Signed-off-by: Miguel Ojeda <[email protected]>
diff --git a/rust/helpers.c b/rust/helpers.c
index 89f4cd1..04b9be46 100644
--- a/rust/helpers.c
+++ b/rust/helpers.c
@@ -53,6 +53,18 @@ __force void *rust_helper_ERR_PTR(long err)
}
EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+ return IS_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+ return PTR_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
+
/*
* We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
* as the Rust `usize` type, so we can use it in contexts where Rust
