1 files changed, 69 insertions, 17 deletions

diff --git a/drivers/net/wireguard/queueing.c b/drivers/net/wireguard/queueing.c
index 71b8e80b58e1..48e7b982a307 100644
--- a/drivers/net/wireguard/queueing.c
+++ b/drivers/net/wireguard/queueing.c
@@ -9,8 +9,7 @@ struct multicore_worker __percpu *
 wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr)
 {
 	int cpu;
-	struct multicore_worker __percpu *worker =
-		alloc_percpu(struct multicore_worker);
+	struct multicore_worker __percpu *worker = alloc_percpu(struct multicore_worker);
 
 	if (!worker)
 		return NULL;
@@ -23,7 +22,7 @@ wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr)
 }
 
 int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
-			 bool multicore, unsigned int len)
+			 unsigned int len)
 {
 	int ret;
 
@@ -31,25 +30,78 @@ int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
 	ret = ptr_ring_init(&queue->ring, len, GFP_KERNEL);
 	if (ret)
 		return ret;
-	if (function) {
-		if (multicore) {
-			queue->worker = wg_packet_percpu_multicore_worker_alloc(
-				function, queue);
-			if (!queue->worker) {
-				ptr_ring_cleanup(&queue->ring, NULL);
-				return -ENOMEM;
-			}
-		} else {
-			INIT_WORK(&queue->work, function);
-		}
+	queue->worker = wg_packet_percpu_multicore_worker_alloc(function, queue);
+	if (!queue->worker) {
+		ptr_ring_cleanup(&queue->ring, NULL);
+		return -ENOMEM;
 	}
 	return 0;
 }
 
-void wg_packet_queue_free(struct crypt_queue *queue, bool multicore)
+void wg_packet_queue_free(struct crypt_queue *queue)
 {
-	if (multicore)
-		free_percpu(queue->worker);
+	free_percpu(queue->worker);
 	WARN_ON(!__ptr_ring_empty(&queue->ring));
 	ptr_ring_cleanup(&queue->ring, NULL);
 }
+
+#define NEXT(skb) ((skb)->prev)
+#define STUB(queue) ((struct sk_buff *)&queue->empty)
+
+void wg_prev_queue_init(struct prev_queue *queue)
+{
+	NEXT(STUB(queue)) = NULL;
+	queue->head = queue->tail = STUB(queue);
+	queue->peeked = NULL;
+	atomic_set(&queue->count, 0);
+	BUILD_BUG_ON(
+		offsetof(struct sk_buff, next) != offsetof(struct prev_queue, empty.next) -
+							offsetof(struct prev_queue, empty) ||
+		offsetof(struct sk_buff, prev) != offsetof(struct prev_queue, empty.prev) -
+							 offsetof(struct prev_queue, empty));
+}
+
+static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
+{
+	WRITE_ONCE(NEXT(skb), NULL);
+	WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
+}
+
+bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
+{
+	if (!atomic_add_unless(&queue->count, 1, MAX_QUEUED_PACKETS))
+		return false;
+	__wg_prev_queue_enqueue(queue, skb);
+	return true;
+}
+
+struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue)
+{
+	struct sk_buff *tail = queue->tail, *next = smp_load_acquire(&NEXT(tail));
+
+	if (tail == STUB(queue)) {
+		if (!next)
+			return NULL;
+		queue->tail = next;
+		tail = next;
+		next = smp_load_acquire(&NEXT(next));
+	}
+	if (next) {
+		queue->tail = next;
+		atomic_dec(&queue->count);
+		return tail;
+	}
+	if (tail != READ_ONCE(queue->head))
+		return NULL;
+	__wg_prev_queue_enqueue(queue, STUB(queue));
+	next = smp_load_acquire(&NEXT(tail));
+	if (next) {
+		queue->tail = next;
+		atomic_dec(&queue->count);
+		return tail;
+	}
+	return NULL;
+}
+
+#undef NEXT
+#undef STUB