usb: rust: mark Device and Interface methods as inline

When building the kernel using llvm-19.1.7-rust-1.85.1-x86_64, the
following symbols are generated:

$ nm vmlinux | grep ' _R'.*usb.*Device | rustfilt
...
ffffffff823f2490 T <kernel::usb::Device as kernel::sync::aref::AlwaysRefCounted>::dec_ref
ffffffff823f2470 T <kernel::usb::Device as kernel::sync::aref::AlwaysRefCounted>::inc_ref
...

$ nm vmlinux | grep ' _R'.*usb.*Interface | rustfilt
ffffffff823f2450 T <kernel::usb::Interface as kernel::sync::aref::AlwaysRefCounted>::dec_ref
ffffffff823f2430 T <kernel::usb::Interface as kernel::sync::aref::AlwaysRefCounted>::inc_ref
...

However, these Rust symbols are trivial wrappers around the
`usb_get_dev`, `usb_put_dev`, `usb_get_intf` and `usb_put_intf`
functions. It doesn't make sense to go through a trivial wrapper
for these functions.

Link: https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Nicolás Antinori <nico.antinori.7@gmail.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260616223614.16444-1-nico.antinori.7@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index bbf85366d2c9..6dfdd64dd617 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -382,6 +382,7 @@ impl<Ctx: device::DeviceContext> AsRef<Device> for Interface<Ctx> {
 
 // SAFETY: Instances of `Interface` are always reference-counted.
 unsafe impl AlwaysRefCounted for Interface {
+    #[inline]
     fn inc_ref(&self) {
         // SAFETY: The invariants of `Interface` guarantee that `self.as_raw()`
         // returns a valid `struct usb_interface` pointer, for which we will
@@ -389,6 +390,7 @@ unsafe impl AlwaysRefCounted for Interface {
         unsafe { bindings::usb_get_intf(self.as_raw()) };
     }
 
+    #[inline]
     unsafe fn dec_ref(obj: NonNull<Self>) {
         // SAFETY: The safety requirements guarantee that the refcount is non-zero.
         unsafe { bindings::usb_put_intf(obj.cast().as_ptr()) }
@@ -433,6 +435,7 @@ kernel::impl_device_context_into_aref!(Device);
 
 // SAFETY: Instances of `Device` are always reference-counted.
 unsafe impl AlwaysRefCounted for Device {
+    #[inline]
     fn inc_ref(&self) {
         // SAFETY: The invariants of `Device` guarantee that `self.as_raw()`
         // returns a valid `struct usb_device` pointer, for which we will
@@ -440,6 +443,7 @@ unsafe impl AlwaysRefCounted for Device {
         unsafe { bindings::usb_get_dev(self.as_raw()) };
     }
 
+    #[inline]
     unsafe fn dec_ref(obj: NonNull<Self>) {
         // SAFETY: The safety requirements guarantee that the refcount is non-zero.
         unsafe { bindings::usb_put_dev(obj.cast().as_ptr()) }