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rust: optimize rust symbol generation for SeqFile

PATCH Applied Kunwu Chan 4 participants 4 messages Mar 17, 2025 – Mar 18, 2025

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Kunwu Chan

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#0 lore raw

PATCH v2 1/1 rust: optimize rust symbol generation for SeqFile

From: Kunwu Chan <[email protected]>

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 <[email protected]>
Co-developed-by Grace Deng <[email protected]>
Signed-off-by Grace Deng <[email protected]>
Signed-off-by Kunwu Chan <[email protected]>

---
Changes in v2:
- Add link and Suggested-by
- Reword commit msg

---
 rust/kernel/seq_file.rs | 1 +
 1 file changed, 1 insertion(+)
rust/kernel/seq_file.rs +1 -0
index 04947c672979..efc4dd09850a 100644
@@ -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 {
Signature · 1 line
2.43.0
reviewer Reviewed-by on v2 1/1
#1 lore raw

Adding Christian Brauner who picked up the original SeqFile patch.

Quoted 13 lines · Kunwu Chan

From: Kunwu Chan <[email protected]>

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.

Quoted 5 lines
Link https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by Alice Ryhl <[email protected]>
Co-developed-by Grace Deng <[email protected]>
Signed-off-by Grace Deng <[email protected]>
Signed-off-by Kunwu Chan <[email protected]>
Reviewed-by Alice Ryhl <[email protected]>
Reviewed-by on v2 1/1
#2 lore raw
In reply to Kunwu Chan
Quoted 12 lines · Kunwu Chan

From: Kunwu Chan <[email protected]>

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.

Quoted 5 lines
Link https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by Alice Ryhl <[email protected]>
Co-developed-by Grace Deng <[email protected]>
Signed-off-by Grace Deng <[email protected]>
Signed-off-by Kunwu Chan <[email protected]>
Reviewed-by Benno Lossin <[email protected]>

---
Cheers,
Benno

Quoted 7 lines

---
Changes in v2:
- Add link and Suggested-by
- Reword commit msg

---
 rust/kernel/seq_file.rs | 1 +
 1 file changed, 1 insertion(+)
maintainer Applied
#3 lore raw
In reply to Kunwu Chan
Quoted 11 lines · Kunwu Chan

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