Re: [PATCH v2] rust: sync: optimize Rust symbol generation for PollCondVar

[Boqun Feng]

On Mon, Mar 17, 2025 at 10:52:05AM +0800, Kunwu Chan wrote:
> 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'.*PollCondVar  | rustfilt
> ... T <kernel::sync::poll::PollCondVar>::new::{closure#0}::{closure#0}::panic_cold_explicit
> ... T <kernel::sync::poll::PollCondVar as kernel::init::PinnedDrop>::drop
> ... T <kernel::sync::poll::PollCondVar as core::ops::drop::Drop>::drop
> 
> This Rust symbol
> (<kernel::sync::poll::PollCondVar as kernel::init::PinnedDrop>::drop)
> is trivial wrappers around the C functions __wake_up_pollfree
> and synchronize_rcu. 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>
> 

Queued for future tests and reviews. Thanks!

Regards,
Boqun

> ---
> Changes in v2:
>  - Add link and Suggested-by
>  - Reword commit msg
> ---
>  rust/kernel/sync/poll.rs | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs
> index d5f17153b424..a4f92c545fec 100644
> --- a/rust/kernel/sync/poll.rs
> +++ b/rust/kernel/sync/poll.rs
> @@ -107,6 +107,7 @@ fn deref(&self) -> &CondVar {
>  
>  #[pinned_drop]
>  impl PinnedDrop for PollCondVar {
> +    #[inline]
>      fn drop(self: Pin<&mut Self>) {
>          // Clear anything registered using `register_wait`.
>          //
> -- 
> 2.43.0
>