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rust: file: optimize rust symbol generation for FileDescriptorReservation

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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
... T <kernel::fs::file::FileDescriptorReservation>::fd_install
... T <kernel::fs::file::FileDescriptorReservation>::get_unused_fd_flags
... 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.

Link: https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Link: https://lore.kernel.org/r/20250317023702.2360726-1-kunwu.chan@linux.dev
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Kunwu Chan 2025-03-17 10:37:02 +08:00 committed by Christian Brauner
parent 2014c95afe
commit e27b0e3c54
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1 changed files with 4 additions and 0 deletions
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4
rust/kernel/fs/file.rs
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@ -392,6 +392,7 @@ pub struct FileDescriptorReservation {
impl FileDescriptorReservation {
/// Creates a new file descriptor reservation.
#[inline]
pub fn get_unused_fd_flags(flags: u32) -> Result<Self> {
// SAFETY: FFI call, there are no safety requirements on `flags`.
let fd: i32 = unsafe { bindings::get_unused_fd_flags(flags) };
@ -405,6 +406,7 @@ impl FileDescriptorReservation {
}
/// Returns the file descriptor number that was reserved.
#[inline]
pub fn reserved_fd(&self) -> u32 {
self.fd
}
@ -413,6 +415,7 @@ impl FileDescriptorReservation {
///
/// The previously reserved file descriptor is bound to `file`. This method consumes the
/// [`FileDescriptorReservation`], so it will not be usable after this call.
#[inline]
pub fn fd_install(self, file: ARef<File>) {
// SAFETY: `self.fd` was previously returned by `get_unused_fd_flags`. We have not yet used
// the fd, so it is still valid, and `current` still refers to the same task, as this type
@ -433,6 +436,7 @@ impl FileDescriptorReservation {
}
impl Drop for FileDescriptorReservation {
#[inline]
fn drop(&mut self) {
// SAFETY: By the type invariants of this type, `self.fd` was previously returned by
// `get_unused_fd_flags`. We have not yet used the fd, so it is still valid, and `current`