[PATCH v6 7/7] add KUnit coverage on ww_mutex/exec implementation

Onur Özkan
2025-09-03T13:14:07Z

Adds coverage for `ww_mutex/exec.rs` implementation.

Signed-off-by: Onur Özkan <work@onurozkan.dev>
---
rust/kernel/sync/lock/ww_mutex/exec.rs | 148 +++++++++++++++++++++++++
1 file changed, 148 insertions(+)

diff --git a/rust/kernel/sync/lock/ww_mutex/exec.rs b/rust/kernel/sync/lock/ww_mutex/exec.rs
index 2f1fc540f0b8..543c5218232a 100644
--- a/rust/kernel/sync/lock/ww_mutex/exec.rs
+++ b/rust/kernel/sync/lock/ww_mutex/exec.rs
@@ -174,3 +174,151 @@ fn cleanup_on_deadlock(&mut self) -> Result {
Ok(())
}
}
+
+#[kunit_tests(rust_kernel_ww_exec)]
+mod tests {
+ use crate::c_str;
+ use crate::prelude::*;
+ use crate::sync::Arc;
+ use pin_init::stack_pin_init;
+
+ use super::*;
+
+ #[test]
+ fn test_exec_context_basic_lock_unlock() -> Result {
+ stack_pin_init!(let class = WwClass::new_wound_wait(c_str!("exec_ctx_basic")));
+
+ let mutex = Arc::pin_init(WwMutex::new(10, &class), GFP_KERNEL)?;
+ let mut ctx = KBox::pin_init(ExecContext::new(&class)?, GFP_KERNEL)?;
+
+ ctx.lock(&mutex)?;
+ ctx.with_locked(&mutex, |v| {
+ assert_eq!(*v, 10);
+ })?;
+
+ ctx.release_all_locks();
+ assert!(!mutex.is_locked());
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_exec_context_with_locked_mutates_data() -> Result {
+ stack_pin_init!(let class = WwClass::new_wound_wait(c_str!("exec_ctx_with_locked")));
+
+ let mutex = Arc::pin_init(WwMutex::new(5, &class), GFP_KERNEL)?;
+ let mut ctx = KBox::pin_init(ExecContext::new(&class)?, GFP_KERNEL)?;
+
+ ctx.lock(&mutex)?;
+
+ ctx.with_locked(&mutex, |v| {
+ assert_eq!(*v, 5);
+ // Increment the value.
+ *v += 7;
+ })?;
+
+ ctx.with_locked(&mutex, |v| {
+ // Check that mutation took effect.
+ assert_eq!(*v, 12);
+ })?;
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_lock_all_success() -> Result {
+ stack_pin_init!(let class = WwClass::new_wound_wait(c_str!("lock_all_ok")));
+
+ let mutex1 = Arc::pin_init(WwMutex::new(1, &class), GFP_KERNEL)?;
+ let mutex2 = Arc::pin_init(WwMutex::new(2, &class), GFP_KERNEL)?;
+ let mut ctx = KBox::pin_init(ExecContext::new(&class)?, GFP_KERNEL)?;
+
+ let res = ctx.lock_all(
+ |ctx| {
+ let _ = ctx.lock(&mutex1)?;
+ let _ = ctx.lock(&mutex2)?;
+ Ok(())
+ },
+ |ctx| {
+ ctx.with_locked(&mutex1, |v| *v += 10)?;
+ ctx.with_locked(&mutex2, |v| *v += 20)?;
+ Ok((
+ ctx.with_locked(&mutex1, |v| *v)?,
+ ctx.with_locked(&mutex2, |v| *v)?,
+ ))
+ },
+ )?;
+
+ assert_eq!(res, (11, 22));
+ assert!(!mutex1.is_locked());
+ assert!(!mutex2.is_locked());
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_with_different_input_type() -> Result {
+ stack_pin_init!(let class = WwClass::new_wound_wait(c_str!("lock_all_ok")));
+
+ let mutex1 = Arc::pin_init(WwMutex::new(1, &class), GFP_KERNEL)?;
+ let mutex2 = Arc::pin_init(WwMutex::new("hello", &class), GFP_KERNEL)?;
+ let mut ctx = KBox::pin_init(ExecContext::new(&class)?, GFP_KERNEL)?;
+
+ ctx.lock_all(
+ |ctx| {
+ ctx.lock(&mutex1)?;
+ ctx.lock(&mutex2)?;
+ Ok(())
+ },
+ |ctx| {
+ ctx.with_locked(&mutex1, |v| assert_eq!(*v, 1))?;
+ ctx.with_locked(&mutex2, |v| assert_eq!(*v, "hello"))?;
+ Ok(())
+ },
+ )?;
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_lock_all_retries_on_deadlock() -> Result {
+ stack_pin_init!(let class = WwClass::new_wound_wait(c_str!("lock_all_retry")));
+
+ let mutex = Arc::pin_init(WwMutex::new(99, &class), GFP_KERNEL)?;
+ let mut ctx = KBox::pin_init(ExecContext::new(&class)?, GFP_KERNEL)?;
+ let mut first_try = true;
+
+ let res = ctx.lock_all(
+ |ctx| {
+ if first_try {
+ first_try = false;
+ // Simulate deadlock on first attempt.
+ return Err(EDEADLK);
+ }
+ ctx.lock(&mutex)
+ },
+ |ctx| {
+ ctx.with_locked(&mutex, |v| {
+ *v += 1;
+ *v
+ })
+ },
+ )?;
+
+ assert_eq!(res, 100);
+ Ok(())
+ }
+
+ #[test]
+ fn test_with_locked_on_unlocked_mutex() -> Result {
+ stack_pin_init!(let class = WwClass::new_wound_wait(c_str!("with_unlocked_mutex")));
+
+ let mutex = Arc::pin_init(WwMutex::new(5, &class), GFP_KERNEL)?;
+ let mut ctx = KBox::pin_init(ExecContext::new(&class)?, GFP_KERNEL)?;
+
+ let ecode = ctx.with_locked(&mutex, |_v| {}).unwrap_err();
+ assert_eq!(EINVAL, ecode);
+
+ Ok(())
+ }
+}
--
2.50.0