1 files changed, 138 insertions, 0 deletions
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c
new file mode 100644
index 000000000..ed5ec5de4
--- /dev/null
+++ b/net/core/gro_cells.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <net/gro_cells.h>
+
+struct gro_cell {
+	struct sk_buff_head	napi_skbs;
+	struct napi_struct	napi;
+};
+
+int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev;
+	struct gro_cell *cell;
+	int res;
+
+	rcu_read_lock();
+	if (unlikely(!(dev->flags & IFF_UP)))
+		goto drop;
+
+	if (!gcells->cells || skb_cloned(skb) || netif_elide_gro(dev)) {
+		res = netif_rx(skb);
+		goto unlock;
+	}
+
+	cell = this_cpu_ptr(gcells->cells);
+
+	if (skb_queue_len(&cell->napi_skbs) > READ_ONCE(netdev_max_backlog)) {
+drop:
+		dev_core_stats_rx_dropped_inc(dev);
+		kfree_skb(skb);
+		res = NET_RX_DROP;
+		goto unlock;
+	}
+
+	__skb_queue_tail(&cell->napi_skbs, skb);
+	if (skb_queue_len(&cell->napi_skbs) == 1)
+		napi_schedule(&cell->napi);
+
+	res = NET_RX_SUCCESS;
+
+unlock:
+	rcu_read_unlock();
+	return res;
+}
+EXPORT_SYMBOL(gro_cells_receive);
+
+/* called under BH context */
+static int gro_cell_poll(struct napi_struct *napi, int budget)
+{
+	struct gro_cell *cell = container_of(napi, struct gro_cell, napi);
+	struct sk_buff *skb;
+	int work_done = 0;
+
+	while (work_done < budget) {
+		skb = __skb_dequeue(&cell->napi_skbs);
+		if (!skb)
+			break;
+		napi_gro_receive(napi, skb);
+		work_done++;
+	}
+
+	if (work_done < budget)
+		napi_complete_done(napi, work_done);
+	return work_done;
+}
+
+int gro_cells_init(struct gro_cells *gcells, struct net_device *dev)
+{
+	int i;
+
+	gcells->cells = alloc_percpu(struct gro_cell);
+	if (!gcells->cells)
+		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
+
+		__skb_queue_head_init(&cell->napi_skbs);
+
+		set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state);
+
+		netif_napi_add(dev, &cell->napi, gro_cell_poll);
+		napi_enable(&cell->napi);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(gro_cells_init);
+
+struct percpu_free_defer {
+	struct rcu_head rcu;
+	void __percpu	*ptr;
+};
+
+static void percpu_free_defer_callback(struct rcu_head *head)
+{
+	struct percpu_free_defer *defer;
+
+	defer = container_of(head, struct percpu_free_defer, rcu);
+	free_percpu(defer->ptr);
+	kfree(defer);
+}
+
+void gro_cells_destroy(struct gro_cells *gcells)
+{
+	struct percpu_free_defer *defer;
+	int i;
+
+	if (!gcells->cells)
+		return;
+	for_each_possible_cpu(i) {
+		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
+
+		napi_disable(&cell->napi);
+		__netif_napi_del(&cell->napi);
+		__skb_queue_purge(&cell->napi_skbs);
+	}
+	/* We need to observe an rcu grace period before freeing ->cells,
+	 * because netpoll could access dev->napi_list under rcu protection.
+	 * Try hard using call_rcu() instead of synchronize_rcu(),
+	 * because we might be called from cleanup_net(), and we
+	 * definitely do not want to block this critical task.
+	 */
+	defer = kmalloc(sizeof(*defer), GFP_KERNEL | __GFP_NOWARN);
+	if (likely(defer)) {
+		defer->ptr = gcells->cells;
+		call_rcu(&defer->rcu, percpu_free_defer_callback);
+	} else {
+		/* We do not hold RTNL at this point, synchronize_net()
+		 * would not be able to expedite this sync.
+		 */
+		synchronize_rcu_expedited();
+		free_percpu(gcells->cells);
+	}
+	gcells->cells = NULL;
+}
+EXPORT_SYMBOL(gro_cells_destroy);