rust: time: add msecs to jiffies conversion

Defines type aliases and conversions for msecs and jiffies.

This is used by Rust Binder for process freezing. There, we want to
sleep until the freeze operation completes, but we want to be able to
abort the process freezing if it doesn't complete within some timeout.
The freeze timeout is supplied in msecs.

Note that we need to convert to jiffies in Binder. It is not enough to
introduce a variant of `CondVar::wait_timeout` that takes the timeout in
msecs because we need to be able to restart the sleep with the remaining
sleep duration if it is interrupted, and if the API takes msecs rather
than jiffies, then that would require a conversion roundtrip jiffies->
msecs->jiffies that is best avoided.

Suggested-by: Boqun Feng <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Tiago Lam <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index cb2d024db51f..b89ecf4e97a0 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -48,6 +48,7 @@ pub mod std_vendor;
 pub mod str;
 pub mod sync;
 pub mod task;
+pub mod time;
 pub mod types;
 pub mod workqueue;