[PATCH] cred: rust: mark Credential methods inline

Alice Ryhl
2025-03-03T15:29:28Z

I'm seeing Binder generating calls to methods on Credential such as
get_secid, inc_ref, and dec_ref without inlining. Since these methods
are really simple wrappers around C functions, mark the methods to
inline to avoid generating these useless small functions.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
rust/kernel/cred.rs | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/rust/kernel/cred.rs b/rust/kernel/cred.rs
index 81d67789b16f..2599f01e8b28 100644
--- a/rust/kernel/cred.rs
+++ b/rust/kernel/cred.rs
@@ -47,6 +47,7 @@ impl Credential {
///
/// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
/// returned [`Credential`] reference.
+ #[inline]
pub unsafe fn from_ptr<'a>(ptr: *const bindings::cred) -> &'a Credential {
// SAFETY: The safety requirements guarantee the validity of the dereference, while the
// `Credential` type being transparent makes the cast ok.
@@ -54,6 +55,7 @@ pub unsafe fn from_ptr<'a>(ptr: *const bindings::cred) -> &'a Credential {
}

/// Get the id for this security context.
+ #[inline]
pub fn get_secid(&self) -> u32 {
let mut secid = 0;
// SAFETY: The invariants of this type ensures that the pointer is valid.
@@ -62,6 +64,7 @@ pub fn get_secid(&self) -> u32 {
}

/// Returns the effective UID of the given credential.
+ #[inline]
pub fn euid(&self) -> Kuid {
// SAFETY: By the type invariant, we know that `self.0` is valid. Furthermore, the `euid`
// field of a credential is never changed after initialization, so there is no potential
@@ -72,11 +75,13 @@ pub fn euid(&self) -> Kuid {

// SAFETY: The type invariants guarantee that `Credential` is always ref-counted.
unsafe impl AlwaysRefCounted for Credential {
+ #[inline]
fn inc_ref(&self) {
// SAFETY: The existence of a shared reference means that the refcount is nonzero.
unsafe { bindings::get_cred(self.0.get()) };
}

+ #[inline]
unsafe fn dec_ref(obj: core::ptr::NonNull<Credential>) {
// SAFETY: The safety requirements guarantee that the refcount is nonzero. The cast is okay
// because `Credential` has the same representation as `struct cred`.

---
base-commit: a64dcfb451e254085a7daee5fe51bf22959d52d3
change-id: 20250303-inline-cred-1d1050785e5c

Best regards,
--
Alice Ryhl <aliceryhl@google.com>