Received-SPF: pass (google.com: domain of linux-kernel+bounces-109040-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Kuan-Wei Chiu <visitorckw@gmail.com>
To: colyli@suse.de,
	kent.overstreet@linux.dev,
	msakai@redhat.com,
	peterz@infradead.org,
	mingo@redhat.com,
	acme@kernel.org,
	namhyung@kernel.org,
	akpm@linux-foundation.org
Cc: bfoster@redhat.com,
	mark.rutland@arm.com,
	alexander.shishkin@linux.intel.com,
	jolsa@kernel.org,
	irogers@google.com,
	adrian.hunter@intel.com,
	jserv@ccns.ncku.edu.tw,
	dm-devel@lists.linux.dev,
	linux-bcache@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-bcachefs@vger.kernel.org,
	linux-perf-users@vger.kernel.org,
	Kuan-Wei Chiu <visitorckw@gmail.com>
Subject: [PATCH v2 06/15] lib min_heap: Add min_heap_peek()
Date: Wed, 20 Mar 2024 22:54:08 +0800
Message-Id: <20240320145417.336208-7-visitorckw@gmail.com>
In-Reply-To: <20240320145417.336208-1-visitorckw@gmail.com>
References: <20240320145417.336208-1-visitorckw@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

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