[PATCH v2 06/15] lib min_heap: Add min_heap_peek()

[Kuan-Wei Chiu <visitorckw@gmail.com>]

Add min_heap_peek() function to retrieve a pointer to the smallest
element. The pointer is cast to the appropriate type of heap elements.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
---
 include/linux/min_heap.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index ed462f194b88..7c1fd1ddc71a 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -56,6 +56,16 @@ void __min_heap_init(struct __min_heap *heap, void *data, int size)
 #define min_heap_init(_heap, _data, _size)	\
 	__min_heap_init(&(_heap)->heap, _data, _size)
 
+/* Get the minimum element from the heap. */
+static __always_inline
+void *__min_heap_peek(struct __min_heap *heap)
+{
+	return heap->nr ? heap->data : NULL;
+}
+
+#define min_heap_peek(_heap)	\
+	(__minheap_cast(_heap) __min_heap_peek(&(_heap)->heap))
+
 /* Sift the element at pos down the heap. */
 static __always_inline
 void __min_heapify(struct __min_heap *heap, int pos, size_t elem_size,
-- 
2.34.1