[PATCH] rust: kernel: drop repetition in offset_of macro

From: Wei Liu
Date: Fri Dec 16 2022 - 12:49:53 EST


It doesn't make sense to allow multiple fields to be specified in
offset_of.

No functional change.

Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
---
Cc: Miguel Ojeda <ojeda@xxxxxxxxxx>
Cc: Alex Gaynor <alex.gaynor@xxxxxxxxx>
Cc: Wedson Almeida Filho <wedsonaf@xxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Gary Guo <gary@xxxxxxxxxxx>
Cc: Björn Roy Baron <bjorn3_gh@xxxxxxxxxxxxxx>
---
rust/kernel/lib.rs | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 6a322effa60c..2f3601e4e27e 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -208,7 +208,7 @@ impl<'a> Drop for KParamGuard<'a> {
/// ```
#[macro_export]
macro_rules! offset_of {
- ($type:ty, $($f:tt)*) => {{
+ ($type:ty, $f:tt) => {{
let tmp = core::mem::MaybeUninit::<$type>::uninit();
let outer = tmp.as_ptr();
// To avoid warnings when nesting `unsafe` blocks.
@@ -216,12 +216,14 @@ macro_rules! offset_of {
// SAFETY: The pointer is valid and aligned, just not initialised; `addr_of` ensures that
// we don't actually read from `outer` (which would be UB) nor create an intermediate
// reference.
- let inner = unsafe { core::ptr::addr_of!((*outer).$($f)*) } as *const u8;
+ let inner = unsafe { core::ptr::addr_of!((*outer).$f) } as *const u8;
// To avoid warnings when nesting `unsafe` blocks.
#[allow(unused_unsafe)]
// SAFETY: The two pointers are within the same allocation block.
- unsafe { inner.offset_from(outer as *const u8) }
- }}
+ unsafe {
+ inner.offset_from(outer as *const u8)
+ }
+ }};
}

/// Produces a pointer to an object from a pointer to one of its fields.
--
2.35.1