[PATCH v2 5/6] rust: pci: io: remove overloaded Io methods of ConfigSpace

Alexandre Courbot
2026-02-06T06:00:53Z

Since `ConfigSpace` now has the relevant implementations of `IoCapable`,
the default methods of `Io` can be used in place of the overloaded ones.
Remove them as well as the macros generating them.

Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Acked-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
rust/kernel/io.rs | 3 ---
rust/kernel/pci/io.rs | 70 ---------------------------------------------------
2 files changed, 73 deletions(-)

diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index 06856d6a9b46..9874edda2b28 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -226,8 +226,6 @@ macro_rules! define_read {
}
};
}
-pub(crate) use define_read;
-
macro_rules! define_write {
(infallible, $(#[$attr:meta])* $vis:vis $name:ident, $call_macro:ident($c_fn:ident) <-
$type_name:ty) => {
@@ -259,7 +257,6 @@ macro_rules! define_write {
}
};
}
-pub(crate) use define_write;

/// Checks whether an access of type `U` at the given `offset`
/// is valid within this region.
diff --git a/rust/kernel/pci/io.rs b/rust/kernel/pci/io.rs
index 8c8aab2e3f22..ae78676c927f 100644
--- a/rust/kernel/pci/io.rs
+++ b/rust/kernel/pci/io.rs
@@ -8,8 +8,6 @@
device,
devres::Devres,
io::{
- define_read,
- define_write,
Io,
IoCapable,
IoKnownSize,
@@ -85,63 +83,6 @@ pub struct ConfigSpace<'a, S: ConfigSpaceKind = Extended> {
_marker: PhantomData,
}

-/// Internal helper macros used to invoke C PCI configuration space read functions.
-///
-/// This macro is intended to be used by higher-level PCI configuration space access macros
-/// (define_read) and provides a unified expansion for infallible vs. fallible read semantics. It
-/// emits a direct call into the corresponding C helper and performs the required cast to the Rust
-/// return type.
-///
-/// # Parameters
-///
-/// * `$c_fn` – The C function performing the PCI configuration space write.
-/// * `$self` – The I/O backend object.
-/// * `$ty` – The type of the value to read.
-/// * `$addr` – The PCI configuration space offset to read.
-///
-/// This macro does not perform any validation; all invariants must be upheld by the higher-level
-/// abstraction invoking it.
-macro_rules! call_config_read {
- (infallible, $c_fn:ident, $self:ident, $ty:ty, $addr:expr) => {{
- let mut val: $ty = 0;
- // SAFETY: By the type invariant `$self.pdev` is a valid address.
- // CAST: The offset is cast to `i32` because the C functions expect a 32-bit signed offset
- // parameter. PCI configuration space size is at most 4096 bytes, so the value always fits
- // within `i32` without truncation or sign change.
- // Return value from C function is ignored in infallible accessors.
- let _ret = unsafe { bindings::$c_fn($self.pdev.as_raw(), $addr as i32, &mut val) };
- val
- }};
-}
-
-/// Internal helper macros used to invoke C PCI configuration space write functions.
-///
-/// This macro is intended to be used by higher-level PCI configuration space access macros
-/// (define_write) and provides a unified expansion for infallible vs. fallible read semantics. It
-/// emits a direct call into the corresponding C helper and performs the required cast to the Rust
-/// return type.
-///
-/// # Parameters
-///
-/// * `$c_fn` – The C function performing the PCI configuration space write.
-/// * `$self` – The I/O backend object.
-/// * `$ty` – The type of the written value.
-/// * `$addr` – The configuration space offset to write.
-/// * `$value` – The value to write.
-///
-/// This macro does not perform any validation; all invariants must be upheld by the higher-level
-/// abstraction invoking it.
-macro_rules! call_config_write {
- (infallible, $c_fn:ident, $self:ident, $ty:ty, $addr:expr, $value:expr) => {
- // SAFETY: By the type invariant `$self.pdev` is a valid address.
- // CAST: The offset is cast to `i32` because the C functions expect a 32-bit signed offset
- // parameter. PCI configuration space size is at most 4096 bytes, so the value always fits
- // within `i32` without truncation or sign change.
- // Return value from C function is ignored in infallible accessors.
- let _ret = unsafe { bindings::$c_fn($self.pdev.as_raw(), $addr as i32, $value) };
- };
-}
-
/// Implements [`IoCapable`] on [`ConfigSpace`] for `$ty` using `$read_fn` and `$write_fn`.
macro_rules! impl_config_space_io_capable {
($ty:ty, $read_fn:ident, $write_fn:ident) => {
@@ -190,17 +131,6 @@ fn addr(&self) -> usize {
fn maxsize(&self) -> usize {
self.pdev.cfg_size().into_raw()
}
-
- // PCI configuration space does not support fallible operations.
- // The default implementations from the Io trait are not used.
-
- define_read!(infallible, read8, call_config_read(pci_read_config_byte) -> u8);
- define_read!(infallible, read16, call_config_read(pci_read_config_word) -> u16);
- define_read!(infallible, read32, call_config_read(pci_read_config_dword) -> u32);
-
- define_write!(infallible, write8, call_config_write(pci_write_config_byte) <- u8);
- define_write!(infallible, write16, call_config_write(pci_write_config_word) <- u16);
- define_write!(infallible, write32, call_config_write(pci_write_config_dword) <- u32);
}

impl<'a, S: ConfigSpaceKind> IoKnownSize for ConfigSpace<'a, S> {

--
2.53.0