lib min_heap: add min_heap_peek()
Add min_heap_peek() to retrieve a pointer to the smallest element. The
pointer is cast to the appropriate type of heap elements.
Link: https://lkml.kernel.org/r/20240524152958.919343-7-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index b384a4e..d9c4ae7 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -53,6 +53,16 @@ void __min_heap_init(min_heap_char *heap, void *data, int size)
#define min_heap_init(_heap, _data, _size) \
__min_heap_init((min_heap_char *)_heap, _data, _size)
+/* Get the minimum element from the heap. */
+static __always_inline
+void *__min_heap_peek(struct min_heap_char *heap)
+{
+ return heap->nr ? heap->data : NULL;
+}
+
+#define min_heap_peek(_heap) \
+ (__minheap_cast(_heap) __min_heap_peek((min_heap_char *)_heap))
+
/* Sift the element at pos down the heap. */
static __always_inline
void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
