[PATCH RFC net-next v4 05/14] xsk: add direct xmit in batch function

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

Add batch xmit logic.

Only grabbing the lock and disable bottom half once and sent all
the aggregated packets in one loop. Via skb->list, the already built
skbs can be handled one by one.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/net/xdp_sock.h |  1 +
 net/core/dev.c         | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 2151aab8f0a1..0609e3b04279 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -141,6 +141,7 @@ struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 			      struct sk_buff *allocated_skb,
 			      struct xdp_desc *desc);
 int xsk_alloc_batch_skb(struct xdp_sock *xs, u32 nb_pkts, u32 nb_descs, int *err);
+int xsk_direct_xmit_batch(struct xdp_sock *xs, struct net_device *dev);
 
 /**
  *  xsk_tx_metadata_to_compl - Save enough relevant metadata information
diff --git a/net/core/dev.c b/net/core/dev.c
index 4519f0e59beb..e33a2406d8ca 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -163,6 +163,7 @@
 #include <net/page_pool/memory_provider.h>
 #include <net/rps.h>
 #include <linux/phy_link_topology.h>
+#include <net/xdp_sock.h>
 
 #include "dev.h"
 #include "devmem.h"
@@ -4893,6 +4894,46 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
 }
 EXPORT_SYMBOL(__dev_queue_xmit);
 
+int xsk_direct_xmit_batch(struct xdp_sock *xs, struct net_device *dev)
+{
+	u16 queue_id = xs->queue_id;
+	struct netdev_queue *txq = netdev_get_tx_queue(dev, queue_id);
+	struct sk_buff_head *send_queue = &xs->batch.send_queue;
+	int ret = NETDEV_TX_BUSY;
+	struct sk_buff *skb;
+
+	local_bh_disable();
+	HARD_TX_LOCK(dev, txq, smp_processor_id());
+	while ((skb = __skb_dequeue(send_queue)) != NULL) {
+		struct sk_buff *orig_skb = skb;
+		bool again = false;
+
+		skb = validate_xmit_skb_list(skb, dev, &again);
+		if (skb != orig_skb) {
+			dev_core_stats_tx_dropped_inc(dev);
+			kfree_skb_list(skb);
+			ret = NET_XMIT_DROP;
+			break;
+		}
+
+		if (netif_xmit_frozen_or_drv_stopped(txq)) {
+			__skb_queue_head(send_queue, skb);
+			break;
+		}
+		skb_set_queue_mapping(skb, queue_id);
+		ret = netdev_start_xmit(skb, dev, txq, false);
+		if (ret != NETDEV_TX_OK) {
+			if (ret == NETDEV_TX_BUSY)
+				__skb_queue_head(send_queue, skb);
+			break;
+		}
+	}
+	HARD_TX_UNLOCK(dev, txq);
+	local_bh_enable();
+
+	return ret;
+}
+
 int __dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
 {
 	struct net_device *dev = skb->dev;
-- 
2.41.3