When building the kernel using the llvm-22.1.0-rust-1.93.1-x86_64
toolchain provided by kernel.org with ARCH=x86_64, the following symbols
are generated:

$ nm vmlinux | grep ' _R'.*Completion | rustfilt
ffffffff81827930 T <kernel::sync::completion::Completion>::complete_all
ffffffff81827950 T <kernel::sync::completion::Completion>::wait_for_completion

These Rust methods are thin wrappers around the C completion helpers
`complete_all` and `wait_for_completion`. Mark them `#[inline]` to keep
the wrapper pattern consistent with other small Rust helper methods.

After applying this patch, the above command will produce no output.

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Fabricio Parra <a@alice0.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://github.com/Rust-for-Linux/linux/issues/1145
Link: https://patch.msgid.link/20260316151056.287-1-a@alice0.com
Link: https://patch.msgid.link/20260605052331.1628-4-boqun@kernel.org

Implement a minimal abstraction for the completion synchronization
primitive.

This initial abstraction only adds complete_all() and
wait_for_completion(), since that is what is required for the subsequent
Devres patch.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250612121817.1621-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>