[PATCH v2] rust: optimize rust symbol generation for SeqFile

From: Kunwu Chan
Date: Sun Mar 16 2025 - 23:05:20 EST


From: Kunwu Chan <kunwu.chan@xxxxxxxxxxx>

When build the kernel using the llvm-18.1.3-rust-1.85.0-x86_64
with ARCH=arm64, the following symbols are generated:

$nm vmlinux | grep ' _R'.*SeqFile | rustfilt
ffff8000805b78ac T <kernel::seq_file::SeqFile>::call_printf

This Rust symbol is trivial wrappers around the C functions seq_printf.
It doesn't make sense to go through a trivial wrapper for its functions,
so mark it inline.

Link: https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
Co-developed-by: Grace Deng <Grace.Deng006@xxxxxxxxx>
Signed-off-by: Grace Deng <Grace.Deng006@xxxxxxxxx>
Signed-off-by: Kunwu Chan <kunwu.chan@xxxxxxxxxxx>

---
Changes in v2:
- Add link and Suggested-by
- Reword commit msg
---
rust/kernel/seq_file.rs | 1 +
1 file changed, 1 insertion(+)

diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs
index 04947c672979..efc4dd09850a 100644
--- a/rust/kernel/seq_file.rs
+++ b/rust/kernel/seq_file.rs
@@ -30,6 +30,7 @@ pub unsafe fn from_raw<'a>(ptr: *mut bindings::seq_file) -> &'a SeqFile {
}

/// Used by the [`seq_print`] macro.
+ #[inline]
pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
// SAFETY: Passing a void pointer to `Arguments` is valid for `%pA`.
unsafe {
--
2.43.0