[PATCH v4 1/7] rust: alloc: add Vec::clear

[Alice Ryhl <aliceryhl@google.com>]

Our custom Vec type is missing the stdlib method `clear`, thus add it.
It will be used in the miscdevice sample.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Tamir Duberstein <tamird@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/alloc/kvec.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index 5798e2c890a2140a12303706578ffa2a85423167..412a2fe3ce79a0681175bf358e8e0f628e77e875 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -413,6 +413,26 @@ pub fn into_raw_parts(self) -> (*mut T, usize, usize) {
         (ptr, len, capacity)
     }
 
+    /// Clears the vector, removing all values.
+    ///
+    /// Note that this method has no effect on the allocated capacity
+    /// of the vector.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = kernel::kvec![1, 2, 3]?;
+    ///
+    /// v.clear();
+    ///
+    /// assert!(v.is_empty());
+    /// # Ok::<(), Error>(())
+    /// ```
+    #[inline]
+    pub fn clear(&mut self) {
+        self.truncate(0);
+    }
+
     /// Ensures that the capacity exceeds the length by at least `additional` elements.
     ///
     /// # Examples

-- 
2.49.0.901.g37484f566f-goog