Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Wei Liu <wei.liu@kernel.org>
To:     rust-for-linux@vger.kernel.org,
        Linux Kernel List <linux-kernel@vger.kernel.org>
Cc:     Wei Liu <wei.liu@kernel.org>, Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= <bjorn3_gh@protonmail.com>
Subject: [PATCH] rust: kernel: drop repetition in offset_of macro
Date:   Fri, 16 Dec 2022 17:49:27 +0000
Message-Id: <20221216174927.1008629-1-wei.liu@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@kernel.org>
---
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
---
 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