Re: [PATCH] rust: file: optimize rust symbol generation for FileDescriptorReservation

[Kunwu Chan]

On 2025/3/13 18:47, Alice Ryhl wrote:
> On Thu, Mar 13, 2025 at 04:45:25PM +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'.*FileDescriptorReservation | rustfilt
> > ffff8000805b6ef0 T <kernel::fs::file::FileDescriptorReservation>
> > 						::fd_install
> > ffff8000805b6e60 T <kernel::fs::file::FileDescriptorReservation>
> > 						::get_unused_fd_flags
> > ffff8000805b6f08 T <kernel::fs::file::FileDescriptorReservation
> > 					 as core::ops::drop::Drop>::drop
> >
> > These Rust symbols are trivial wrappers around the C functions
> > fd_install, put_unused_fd and put_task_struct.It
> > doesn't make sense to go through a trivial wrapper for these
> > functions, so mark them inline.
> >
> > After doing so, the above symbol will not in output.
> >
> > Signed-off-by: Kunwu Chan <kunwu.chan@xxxxxxxxxxx>
> > Co-developed-by: Grace Deng <Grace.Deng006@xxxxxxxxx>
> > Signed-off-by: Grace Deng <Grace.Deng006@xxxxxxxxx>
> A few notes:
>
> * Your own Signed-off-by must always be last.
> * You're missing Link: and Suggested-by: tags.

Thanks for the reply.

I'll change my own Signed-off-by be last and add Link and Suggested-by 
as the following:

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>

> * There are some grammar issues, e.g. a missing space before "It" and
>    the phrase "will not in output" is not good.
I'll  add a space before "It" and remove the last line.
> * Let's also add the marker to `reserved_fd` to be on the safe side.
Sure, I'll make 'reserved_fd ' inline in v2.
> * I think it is easier to read the symbols if you list each sybmol on
>    one line like this:
>
> ffff8000805b6ef0 T <kernel::fs::file::FileDescriptorReservation>::fd_install
> ffff8000805b6e60 T <kernel::fs::file::FileDescriptorReservation>::get_unused_fd_flags
> ffff8000805b6f08 T <kernel::fs::file::FileDescriptorReservation as core::ops::drop::Drop>::drop

If in one line, checkpatch.pl will report a warning:

WARNING:Prefer a maximum 75 chars per line (possible unwrapped commit 
description?)

If no need to  bother with the warning, I'll change it to one line in v2.

> Alice



--
Thanks,
  Kunwu.Chan(Tao.chan)