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

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

[Kunwu Chan]

From: Kunwu Chan <kunwu.chan@hotmail.com>

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@google.com>
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>

---
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

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

[Alice Ryhl]

Adding Christian Brauner who picked up the original SeqFile patch.

On Mon, Mar 17, 2025 at 4:05 AM Kunwu Chan <kunwu.chan@linux.dev> wrote:
>
> From: Kunwu Chan <kunwu.chan@hotmail.com>
>
> 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@google.com>
> Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
> Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
> Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

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

[Benno Lossin]

On Mon Mar 17, 2025 at 4:04 AM CET, Kunwu Chan wrote:
> From: Kunwu Chan <kunwu.chan@hotmail.com>
>
> 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@google.com>
> Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
> Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
> Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>

Reviewed-by: Benno Lossin <benno.lossin@proton.me>

---
Cheers,
Benno

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

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

[Christian Brauner]

On Mon, 17 Mar 2025 11:04:18 +0800, Kunwu Chan wrote:
> 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.
> 
> [...]

Applied to the vfs-6.15.rust branch of the vfs/vfs.git tree.
Patches in the vfs-6.15.rust branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.15.rust

[1/1] rust: optimize rust symbol generation for SeqFile
      https://git.kernel.org/vfs/vfs/c/0b9817caac1d