Commit 878620c5 authored by Kunwu Chan's avatar Kunwu Chan Committed by Miguel Ojeda
Browse files

rust: page: optimize rust symbol generation for Page 

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'.*Page | rustfilt
ffff8000805b6f98 T <kernel::page::Page>::alloc_page
ffff8000805b715c T <kernel::page::Page>::fill_zero_raw
ffff8000805b720c T <kernel::page::Page>::copy_from_user_slice_raw
ffff8000805b6fb4 T <kernel::page::Page>::read_raw
ffff8000805b7088 T <kernel::page::Page>::write_raw
ffff8000805b72fc T <kernel::page::Page as core::ops::drop::Drop>::drop

These Rust symbols(alloc_page and drop) are trivial wrappers around the C
functions alloc_pages and __free_pages. It doesn't make sense to go
through a trivial wrapper for these functions, so mark them inline.

Link: https://github.com/Rust-for-Linux/linux/issues/1145


Suggested-by: default avatarAlice Ryhl <aliceryhl@google.com>
Co-developed-by: default avatarGrace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: default avatarGrace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: default avatarKunwu Chan <kunwu.chan@hotmail.com>
Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250321080124.484647-1-kunwu.chan@linux.dev


[ Removed spurious colon in title. - Miguel ]
Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent 82f2b0b9

rust/kernel/page.rs

+2 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ impl Page { 
    /// let page = Page::alloc_page(GFP_KERNEL | __GFP_ZERO)?;

    /// # Ok::<(), kernel::alloc::AllocError>(())

    /// ```

    #[inline]

    pub fn alloc_page(flags: Flags) -> Result<Self, AllocError> {

        // SAFETY: Depending on the value of `gfp_flags`, this call may sleep. Other than that, it

        // is always safe to call this method.
@@ -251,6 +252,7 @@ pub unsafe fn copy_from_user_slice_raw( 
}



impl Drop for Page {

    #[inline]

    fn drop(&mut self) {

        // SAFETY: By the type invariants, we have ownership of the page and can free it.

        unsafe { bindings::__free_pages(self.page.as_ptr(), 0) };