Merge branch 'stmmac-xdp-zc'

Ong Boon Leong says:

====================
stmmac: add XDP ZC support

This is the v2 patch series to add XDP ZC support to stmmac driver.

Summary of v2 patch change:-

6/7: fix synchronize_rcu() is called stmmac_disable_all_queues() that is
     used by ndo_setup_tc().

 ########################################################################

Continuous burst traffics are generated by pktgen script and in the midst
of each packet processing operation by xdpsock the following tc-loop.sh
script is looped continuously:-

 #!/bin/bash
 tc qdisc del dev eth0 parent root
 tc qdisc add dev eth0 ingress
 tc qdisc add dev eth0 root mqprio num_tc 4 map 0 1 2 3 0 0 0 0 0 0 0 0 0 0 0 0 queues 1@0 1@1 1@2 1@3 hw 0
 tc filter add dev eth0 parent ffff: protocol 802.1Q flower vlan_prio 0 hw_tc 0
 tc filter add dev eth0 parent ffff: protocol 802.1Q flower vlan_prio 1 hw_tc 1
 tc filter add dev eth0 parent ffff: protocol 802.1Q flower vlan_prio 2 hw_tc 2
 tc filter add dev eth0 parent ffff: protocol 802.1Q flower vlan_prio 3 hw_tc 3
 tc qdisc list dev eth0
 tc filter show dev eth0 ingress

 On different ssh terminal
 $ while true; do ./tc-loop.sh; sleep 1; done

The v2 patch series have been tested using the xdpsock app:
 $ ./xdpsock -i eth0 -l -z

From xdpsock poller pps report and dmesg, we don't find any warning
related to rcu and the only difference when the script is executed is
the pps rate drops momentarily.

 sock0@eth0:0 l2fwd xdp-drv
                   pps            pkts           1.00
rx                 436347         191361334
tx                 436411         191361334

 sock0@eth0:0 l2fwd xdp-drv
                   pps            pkts           1.00
rx                 254117         191615476
tx                 254053         191615412

 sock0@eth0:0 l2fwd xdp-drv
                   pps            pkts           1.00
rx                 466395         192081924
tx                 466395         192081860

 sock0@eth0:0 l2fwd xdp-drv
                   pps            pkts           1.00
rx                 287410         192369365
tx                 287474         192369365

 sock0@eth0:0 l2fwd xdp-drv
                   pps            pkts           1.00
rx                 395853         192765329
tx                 395789         192765265

 sock0@eth0:0 l2fwd xdp-drv
                   pps            pkts           1.00
rx                 466132         193231514
tx                 466132         193231450

 ########################################################################

Based on the above result, the fix looks promising. Appreciate that if
community can help to review the patch series and provide me feedback
for improvement.
====================

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -40,6 +40,7 @@ enum stmmac_txbuf_type {
 	STMMAC_TXBUF_T_SKB,
 	STMMAC_TXBUF_T_XDP_TX,
 	STMMAC_TXBUF_T_XDP_NDO,
+	STMMAC_TXBUF_T_XSK_TX,
 };
 
 struct stmmac_tx_info {
@@ -69,6 +70,8 @@ struct stmmac_tx_queue {
 		struct xdp_frame **xdpf;
 	};
 	struct stmmac_tx_info *tx_skbuff_dma;
+	struct xsk_buff_pool *xsk_pool;
+	u32 xsk_frames_done;
 	unsigned int cur_tx;
 	unsigned int dirty_tx;
 	dma_addr_t dma_tx_phy;
@@ -77,9 +80,14 @@ struct stmmac_tx_queue {
 };
 
 struct stmmac_rx_buffer {
-	struct page *page;
-	dma_addr_t addr;
-	__u32 page_offset;
+	union {
+		struct {
+			struct page *page;
+			dma_addr_t addr;
+			__u32 page_offset;
+		};
+		struct xdp_buff *xdp;
+	};
 	struct page *sec_page;
 	dma_addr_t sec_addr;
 };
@@ -88,6 +96,7 @@ struct stmmac_rx_queue {
 	u32 rx_count_frames;
 	u32 queue_index;
 	struct xdp_rxq_info xdp_rxq;
+	struct xsk_buff_pool *xsk_pool;
 	struct page_pool *page_pool;
 	struct stmmac_rx_buffer *buf_pool;
 	struct stmmac_priv *priv_data;
@@ -95,6 +104,7 @@ struct stmmac_rx_queue {
 	struct dma_desc *dma_rx ____cacheline_aligned_in_smp;
 	unsigned int cur_rx;
 	unsigned int dirty_rx;
+	unsigned int buf_alloc_num;
 	u32 rx_zeroc_thresh;
 	dma_addr_t dma_rx_phy;
 	u32 rx_tail_addr;
@@ -109,6 +119,7 @@ struct stmmac_rx_queue {
 struct stmmac_channel {
 	struct napi_struct rx_napi ____cacheline_aligned_in_smp;
 	struct napi_struct tx_napi ____cacheline_aligned_in_smp;
+	struct napi_struct rxtx_napi ____cacheline_aligned_in_smp;
 	struct stmmac_priv *priv_data;
 	spinlock_t lock;
 	u32 index;
@@ -283,6 +294,7 @@ struct stmmac_priv {
 	struct stmmac_rss rss;
 
 	/* XDP BPF Program */
+	unsigned long *af_xdp_zc_qps;
 	struct bpf_prog *xdp_prog;
 };
 
@@ -328,6 +340,12 @@ static inline unsigned int stmmac_rx_offset(struct stmmac_priv *priv)
 	return 0;
 }
 
+void stmmac_disable_rx_queue(struct stmmac_priv *priv, u32 queue);
+void stmmac_enable_rx_queue(struct stmmac_priv *priv, u32 queue);
+void stmmac_disable_tx_queue(struct stmmac_priv *priv, u32 queue);
+void stmmac_enable_tx_queue(struct stmmac_priv *priv, u32 queue);
+int stmmac_xsk_wakeup(struct net_device *dev, u32 queue, u32 flags);
+
 #if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
 void stmmac_selftest_run(struct net_device *dev,
 			 struct ethtool_test *etest, u64 *buf);

drivers/net/ethernet/stmicro/stmmac/stmmac_xdp.c

 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2021, Intel Corporation. */
 
+#include <net/xdp_sock_drv.h>
+
 #include "stmmac.h"
 #include "stmmac_xdp.h"
 
+static int stmmac_xdp_enable_pool(struct stmmac_priv *priv,
+				  struct xsk_buff_pool *pool, u16 queue)
+{
+	struct stmmac_channel *ch = &priv->channel[queue];
+	bool need_update;
+	u32 frame_size;
+	int err;
+
+	if (queue >= priv->plat->rx_queues_to_use ||
+	    queue >= priv->plat->tx_queues_to_use)
+		return -EINVAL;
+
+	frame_size = xsk_pool_get_rx_frame_size(pool);
+	/* XDP ZC does not span multiple frame, make sure XSK pool buffer
+	 * size can at least store Q-in-Q frame.
+	 */
+	if (frame_size < ETH_FRAME_LEN + VLAN_HLEN * 2)
+		return -EOPNOTSUPP;
+
+	err = xsk_pool_dma_map(pool, priv->device, STMMAC_RX_DMA_ATTR);
+	if (err) {
+		netdev_err(priv->dev, "Failed to map xsk pool\n");
+		return err;
+	}
+
+	need_update = netif_running(priv->dev) && stmmac_xdp_is_enabled(priv);
+
+	if (need_update) {
+		stmmac_disable_rx_queue(priv, queue);
+		stmmac_disable_tx_queue(priv, queue);
+		napi_disable(&ch->rx_napi);
+		napi_disable(&ch->tx_napi);
+	}
+
+	set_bit(queue, priv->af_xdp_zc_qps);
+
+	if (need_update) {
+		napi_enable(&ch->rxtx_napi);
+		stmmac_enable_rx_queue(priv, queue);
+		stmmac_enable_tx_queue(priv, queue);
+
+		err = stmmac_xsk_wakeup(priv->dev, queue, XDP_WAKEUP_RX);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int stmmac_xdp_disable_pool(struct stmmac_priv *priv, u16 queue)
+{
+	struct stmmac_channel *ch = &priv->channel[queue];
+	struct xsk_buff_pool *pool;
+	bool need_update;
+
+	if (queue >= priv->plat->rx_queues_to_use ||
+	    queue >= priv->plat->tx_queues_to_use)
+		return -EINVAL;
+
+	pool = xsk_get_pool_from_qid(priv->dev, queue);
+	if (!pool)
+		return -EINVAL;
+
+	need_update = netif_running(priv->dev) && stmmac_xdp_is_enabled(priv);
+
+	if (need_update) {
+		stmmac_disable_rx_queue(priv, queue);
+		stmmac_disable_tx_queue(priv, queue);
+		synchronize_rcu();
+		napi_disable(&ch->rxtx_napi);
+	}
+
+	xsk_pool_dma_unmap(pool, STMMAC_RX_DMA_ATTR);
+
+	clear_bit(queue, priv->af_xdp_zc_qps);
+
+	if (need_update) {
+		napi_enable(&ch->rx_napi);
+		napi_enable(&ch->tx_napi);
+		stmmac_enable_rx_queue(priv, queue);
+		stmmac_enable_tx_queue(priv, queue);
+	}
+
+	return 0;
+}
+
+int stmmac_xdp_setup_pool(struct stmmac_priv *priv, struct xsk_buff_pool *pool,
+			  u16 queue)
+{
+	return pool ? stmmac_xdp_enable_pool(priv, pool, queue) :
+		      stmmac_xdp_disable_pool(priv, queue);
+}
+
 int stmmac_xdp_set_prog(struct stmmac_priv *priv, struct bpf_prog *prog,
 			struct netlink_ext_ack *extack)
 {

drivers/net/ethernet/stmicro/stmmac/stmmac_xdp.h

@@ -5,7 +5,10 @@
 #define _STMMAC_XDP_H_
 
 #define STMMAC_MAX_RX_BUF_SIZE(num)	(((num) * PAGE_SIZE) - XDP_PACKET_HEADROOM)
+#define STMMAC_RX_DMA_ATTR	(DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)
 
+int stmmac_xdp_setup_pool(struct stmmac_priv *priv, struct xsk_buff_pool *pool,
+			  u16 queue);
 int stmmac_xdp_set_prog(struct stmmac_priv *priv, struct bpf_prog *prog,
 			struct netlink_ext_ack *extack);