Add missing #[inline] markers to trivial wrappers around C functions

When writing abstractions around core C apis, we often have Rust functions that do nothing other than call a C function. In those cases, we don't want the generated code to have a trivial Rust wrapper around the C function — Rust should inline it and generate a direct call into C.

However, in some cases that requires an #[inline] marker. Many methods in the kernel is missing it, and so this issue tracks such additions.

A few cases where I know that this is happening:

rust/kernel/task.rs
rust/kernel/page.rs
rust/kernel/sync/condvar.rs
rust/kernel/fs.rs specifically FileDescriptorReservation
rust/kernel/seq_file.rs
rust/kernel/uaccess.rs

To find these, you can inspect the Rust symbols yourself by building the kernel and running this command:

nm vmlinux | grep ' _R' | rustfilt

Examples of good patches that make this kind of change:

If you submit a patch that makes this kind of change, please make sure to have a good commit message (see the examples above).

This requires submitting a proper patch to the LKML and the Rust for Linux mailing list. Please recall to test your changes (including generating the documentation if changed, running the Rust doctests if changed, etc.), to use a proper title for the commit, to sign your commit under the Developer's Certificate of Origin and to add a Suggested-by: tag and a Link: tag to this issue. Please see https://docs.kernel.org/process/submitting-patches.html and https://rust-for-linux.com/contributing for details.

Please take this issue only if you are new to the kernel development process and you would like to use it as a test to submit your first patch to the kernel. Please do not take it if you do not plan to make other contributions to the kernel.

Hello! I would like to tackle this issue

Thanks, please go ahead!

I recommend that you don't try to tackle every single method in one go. Start with one or two files and send a patch just for those, like the example patches did.

Sounds good!

Giving it a try: https://lkml.org/lkml/2025/3/9/512

rust/kernel/faux: mark Registration methods inline

rust: task: mark Task methods inline

@ethancedwards8

Thanks both for the patches!

By the way, please prefer lore.kernel.org for links, e.g. @ethancedwards8's patch is: https://lore.kernel.org/rust-for-linux/20250309-faux-inline-v1-1-c1b692862433@ethancedwards.com/

rust/kernel/faux: mark Registration methods inline

Thanks both for the patches!

By the way, please prefer lore.kernel.org for links, e.g. @ethancedwards8's patch is: https://lore.kernel.org/rust-for-linux/20250309-faux-inline-v1-1-c1b692862433@ethancedwards.com/

Yeah, I typically use lore.kernel.org, but last night when I was sending the patch lore.kernel.org was having some issues (I was getting 504 errors), so I used lkml.org instead. I will use lore.kernel.org exclusively in the future, however

Giving a try for methods in uaccess.

https://lore.kernel.org/all/0100019582fc6956-3b420cce-f122-4a26-8fea-94000b22bc90-000000@email.amazonses.com

#1147

When writing abstractions around core C apis, we often have Rust functions that do nothing other than call a C function. In those cases, we don't want the generated code to have a trivial Rust wrapper around the C function — Rust should inline it and generate a direct call into C.在围绕核心 C API 编写抽象时，我们经常会有 Rust 函数，它们除了调用 C 函数之外什么都不做。在这些情况下，我们不希望生成的代码在 C 函数周围有一个简单的 Rust 包装器——Rust 应该内联它并生成对 C 的直接调用。

However, in some cases that requires an #[inline] marker. Many methods in the kernel is missing it, and so this issue tracks such additions.但是，在某些情况下，这需要 #[inline] 标记。内核中的许多方法都缺少它，因此 issue 跟踪此类添加。

A few cases where I know that this is happening:我知道这种情况正在发生的一些情况：

rust/kernel/task.rs``rust/内核/task.rs

rust/kernel/page.rs

rust/kernel/sync/condvar.rs

rust/kernel/fs.rs specifically FileDescriptorReservation``rust/kernel/fs.rs，特别是 FileDescriptorReservation

rust/kernel/seq_file.rs``rust/内核/seq_file.rs

rust/kernel/uaccess.rs``rust/内核/uaccess.rs

To find these, you can inspect the Rust symbols yourself by building the kernel and running this command:要找到这些，您可以通过构建内核并运行以下命令来自己检查 Rust 符号：
nm vmlinux | grep ' _R' | rustfilt
Examples of good patches that make this kind of change:进行此类更改的良好补丁示例：

Example that fixes rust/kernel/cred.rs修复 rust/kernel/cred.rs 的示例

Example that fixes rust/kernel/security.rs修复 rust/kernel/security.rs 的示例

If you submit a patch that makes this kind of change, please make sure to have a good commit message (see the examples above).如果您提交的补丁进行了此类更改，请确保有一个好的提交消息（请参阅上面的示例）。

This requires submitting a proper patch to the LKML and the Rust for Linux mailing list. Please recall to test your changes (including generating the documentation if changed, running the Rust doctests if changed, etc.), to use a proper title for the commit, to sign your commit under the Developer's Certificate of Origin and to add a Suggested-by: tag and a Link: tag to this issue. Please see https://docs.kernel.org/process/submitting-patches.html and https://rust-for-linux.com/contributing for details.这需要向 LKML 和 Rust for Linux 邮件列表提交适当的补丁。请回想测试您的更改（包括更改后生成文档，如果更改则运行 Rust 文档测试等），为提交使用适当的标题，在开发者的原产地证书下签署您的提交，并为此问题添加 Suggested-by：标签和 Link： 标签。有关详细信息，请参阅 https://docs.kernel.org/process/submitting-patches.html 和 https://rust-for-linux.com/contributing。

Please take this issue only if you are new to the kernel development process and you would like to use it as a test to submit your first patch to the kernel. Please do not take it if you do not plan to make other contributions to the kernel.仅当您不熟悉内核开发过程，并且希望将其用作测试以向内核提交您的第一个补丁时，才请关注此问题。如果您不打算对内核做出其他贡献，请不要接受它。

When writing abstractions around core C apis, we often have Rust functions that do nothing other than call a C function. In those cases, we don't want the generated code to have a trivial Rust wrapper around the C function — Rust should inline it and generate a direct call into C.

However, in some cases that requires an #[inline] marker. Many methods in the kernel is missing it, and so this issue tracks such additions.

A few cases where I know that this is happening:

rust/kernel/task.rs

rust/kernel/page.rs

rust/kernel/sync/condvar.rs

rust/kernel/fs.rs specifically FileDescriptorReservation

rust/kernel/seq_file.rs

rust/kernel/uaccess.rs

To find these, you can inspect the Rust symbols yourself by building the kernel and running this command:
nm vmlinux | grep ' _R' | rustfilt
Examples of good patches that make this kind of change:

Example that fixes rust/kernel/cred.rs

Example that fixes rust/kernel/security.rs

If you submit a patch that makes this kind of change, please make sure to have a good commit message (see the examples above).

This requires submitting a proper patch to the LKML and the Rust for Linux mailing list. Please recall to test your changes (including generating the documentation if changed, running the Rust doctests if changed, etc.), to use a proper title for the commit, to sign your commit under the Developer's Certificate of Origin and to add a Suggested-by: tag and a Link: tag to this issue. Please see https://docs.kernel.org/process/submitting-patches.html and https://rust-for-linux.com/contributing for details.

Please take this issue only if you are new to the kernel development process and you would like to use it as a test to submit your first patch to the kernel. Please do not take it if you do not plan to make other contributions to the kernel.

Thanks for the hint, I'll submit for the unfinished part, allow me to add a Suggested-by tag.

@KunWuChan

Thanks for the hint, I'll submit for the unfinished part, allow me to add a Suggested-by tag.

Hi @KunWuChan, please note the following regarding issues labeled as "good-first-issue":

Please take this issue only if you are new to the kernel development process and you would like to use it as a test to submit your first patch to the kernel.

rust: page: mark Page::nid as inline

rust: sync: completion: Mark inline complete_all and wait_for_completion

usb: rust: mark Device and Interface methods as inline

rust: pci: Mark Device refcount methods inline

i2c: rust: mark I2cAdapter methods as inline

rust: sync: rcu: Mark Guard methods as inline

rust: sync: Mark CondVar::notify_*() inline

rust: sync: Mark PollCondVar::drop() inline

rust: task: Mark Task methods inline

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Add missing `#[inline]` markers to trivial wrappers around C functions #1145

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panosfol commented on Mar 5, 2025

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ethancedwards8 commented on Mar 10, 2025

ojeda commented on Mar 10, 2025

ethancedwards8 commented on Mar 11, 2025

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Add missing `#[inline]` markers to trivial wrappers around C functions #1145