[PATCH v2 09/15] lib min_heap: Add min_heap_sift_up()

[Kuan-Wei Chiu]

Add min_heap_sift_up() to sift up the element at index 'idx' in the
heap.

Signed-off-by: Kuan-Wei Chiu <visitor...@gmail.com>
---
 include/linux/min_heap.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 36023e0be232..af12531474a4 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -194,6 +194,26 @@ void __min_heap_push(struct __min_heap *heap, const void 
*element, size_t elem_s
 #define min_heap_push(_heap, _element, _func)  \
        __min_heap_push(&(_heap)->heap, _element, __minheap_obj_size(_heap), 
_func)
 
+/* Sift up ith element from the heap, O(log2(nr)). */
+static __always_inline
+void __min_heap_sift_up(struct __min_heap *heap, size_t elem_size, size_t idx,
+               const struct min_heap_callbacks *func, void *args)
+{
+       void *data = heap->data;
+       size_t parent;
+
+       while (idx) {
+               parent = (idx - 1) / 2;
+               if (func->less(data + parent * elem_size, data + idx * 
elem_size, args))
+                       break;
+               func->swp(data + parent * elem_size, data + idx * elem_size, 
args);
+               idx = parent;
+       }
+}
+
+#define min_heap_sift_up(_heap, _idx, _func, _args)    \
+       __min_heap_sift_up(&(_heap)->heap, __minheap_obj_size(_heap), _idx, 
_func, _args)
+
 /* Remove ith element from the heap, O(log2(nr)). */
 static __always_inline
 bool __min_heap_del(struct __min_heap *heap, size_t elem_size, size_t idx,
-- 
2.34.1