Merge pull request #151 from wedsonaf/signal

Warn if the caller doesn't check if a signal is pending.

Author: ojeda

drivers/char/rust_example.rs

@@ -102,7 +102,7 @@ impl KernelModule for RustExample {
                 let guard = data.lock();
                 #[allow(clippy::while_immutable_condition)]
                 while *guard != 10 {
-                    cv.wait(&guard);
+                    let _ = cv.wait(&guard);
                 }
             }
             cv.notify_one();
@@ -125,7 +125,7 @@ impl KernelModule for RustExample {
                 let guard = data.lock();
                 #[allow(clippy::while_immutable_condition)]
                 while *guard != 10 {
-                    cv.wait(&guard);
+                    let _ = cv.wait(&guard);
                 }
             }
             cv.notify_one();

rust/kernel/sync/condvar.rs

@@ -64,6 +64,7 @@ impl CondVar {
     /// [`CondVar::notify_all`], or when the thread receives a signal.
     ///
     /// Returns whether there is a signal pending.
+    #[must_use = "wait returns if a signal is pending, so the caller must check the return value"]
     pub fn wait<L: Lock>(&self, guard: &Guard<L>) -> bool {
         let lock = guard.lock;
         let mut wait = MaybeUninit::<bindings::wait_queue_entry>::uninit();