[PATCH 0/7] add XDP support to mvneta driver

[PATCH 0/7] add XDP support to mvneta driver

[Lorenzo Bianconi]

Add XDP support to mvneta driver for devices that rely on software
buffer management. Supported verdicts are:
- XDP_DROP
- XDP_PASS
- XDP_REDIRECT
- XDP_TX
Moreover set ndo_xdp_xmit net_device_ops function pointer in order to support
redirecting from other device (e.g. virtio-net).
Convert mvneta driver to page_pool API.
This series is based on previous work done by Jesper and Ilias.

Changes since RFC:
- implement XDP_TX
- make tx pending buffer list agnostic
- code refactoring
- check if device is running in mvneta_xdp_setup

Lorenzo Bianconi (7):
  net: mvneta: introduce mvneta_update_stats routine
  net: mvneta: introduce page pool API for sw buffer manager
  net: mvneta: rely on build_skb in mvneta_rx_swbm poll routine
  net: mvneta: add basic XDP support
  net: mvneta: move header prefetch in mvneta_swbm_rx_frame
  net: mvneta: make tx buffer array agnostic
  net: mvneta: add XDP_TX support

 drivers/net/ethernet/marvell/Kconfig  |   1 +
 drivers/net/ethernet/marvell/mvneta.c | 627 +++++++++++++++++++-------
 2 files changed, 468 insertions(+), 160 deletions(-)

-- 
2.21.0

[PATCH 1/7] net: mvneta: introduce mvneta_update_stats routine

[Lorenzo Bianconi]

Introduce mvneta_update_stats routine to collect {rx/tx} statistics
(packets and bytes). This is a preliminary patch to add XDP support to
mvneta driver

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 41 +++++++++++++--------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index e49820675c8c..128b9fded959 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -1900,6 +1900,23 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp,
 	}
 }
 
+static void
+mvneta_update_stats(struct mvneta_port *pp, u32 pkts,
+		    u32 len, bool tx)
+{
+	struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
+
+	u64_stats_update_begin(&stats->syncp);
+	if (tx) {
+		stats->tx_packets += pkts;
+		stats->tx_bytes += len;
+	} else {
+		stats->rx_packets += pkts;
+		stats->rx_bytes += len;
+	}
+	u64_stats_update_end(&stats->syncp);
+}
+
 static inline
 int mvneta_rx_refill_queue(struct mvneta_port *pp, struct mvneta_rx_queue *rxq)
 {
@@ -2075,14 +2092,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 		rxq->left_size = 0;
 	}
 
-	if (rcvd_pkts) {
-		struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
-
-		u64_stats_update_begin(&stats->syncp);
-		stats->rx_packets += rcvd_pkts;
-		stats->rx_bytes   += rcvd_bytes;
-		u64_stats_update_end(&stats->syncp);
-	}
+	mvneta_update_stats(pp, rcvd_pkts, rcvd_bytes, false);
 
 	/* return some buffers to hardware queue, one at a time is too slow */
 	refill = mvneta_rx_refill_queue(pp, rxq);
@@ -2206,14 +2216,7 @@ static int mvneta_rx_hwbm(struct napi_struct *napi,
 		napi_gro_receive(napi, skb);
 	}
 
-	if (rcvd_pkts) {
-		struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
-
-		u64_stats_update_begin(&stats->syncp);
-		stats->rx_packets += rcvd_pkts;
-		stats->rx_bytes   += rcvd_bytes;
-		u64_stats_update_end(&stats->syncp);
-	}
+	mvneta_update_stats(pp, rcvd_pkts, rcvd_bytes, false);
 
 	/* Update rxq management counters */
 	mvneta_rxq_desc_num_update(pp, rxq, rx_done, rx_done);
@@ -2459,7 +2462,6 @@ static netdev_tx_t mvneta_tx(struct sk_buff *skb, struct net_device *dev)
 
 out:
 	if (frags > 0) {
-		struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
 		struct netdev_queue *nq = netdev_get_tx_queue(dev, txq_id);
 
 		netdev_tx_sent_queue(nq, len);
@@ -2474,10 +2476,7 @@ static netdev_tx_t mvneta_tx(struct sk_buff *skb, struct net_device *dev)
 		else
 			txq->pending += frags;
 
-		u64_stats_update_begin(&stats->syncp);
-		stats->tx_packets++;
-		stats->tx_bytes  += len;
-		u64_stats_update_end(&stats->syncp);
+		mvneta_update_stats(pp, 1, len, true);
 	} else {
 		dev->stats.tx_dropped++;
 		dev_kfree_skb_any(skb);
-- 
2.21.0

[PATCH 2/7] net: mvneta: introduce page pool API for sw buffer manager

[Lorenzo Bianconi]

Use the page_pool api for allocations and DMA handling instead of
__dev_alloc_page()/dma_map_page() and free_page()/dma_unmap_page().
Pages are unmapped using page_pool_release_page before packets
go into the network stack.

The page_pool API offers buffer recycling capabilities for XDP but
allocates one page per packet, unless the driver splits and manages
the allocated page.
This is a preliminary patch to add XDP support to mvneta driver

Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/Kconfig  |  1 +
 drivers/net/ethernet/marvell/mvneta.c | 76 ++++++++++++++++++++-------
 2 files changed, 58 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/marvell/Kconfig b/drivers/net/ethernet/marvell/Kconfig
index fb942167ee54..3d5caea096fb 100644
--- a/drivers/net/ethernet/marvell/Kconfig
+++ b/drivers/net/ethernet/marvell/Kconfig
@@ -61,6 +61,7 @@ config MVNETA
 	depends on ARCH_MVEBU || COMPILE_TEST
 	select MVMDIO
 	select PHYLINK
+	select PAGE_POOL
 	---help---
 	  This driver supports the network interface units in the
 	  Marvell ARMADA XP, ARMADA 370, ARMADA 38x and
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 128b9fded959..8beae0e1eda7 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -37,6 +37,7 @@
 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <net/tso.h>
+#include <net/page_pool.h>
 
 /* Registers */
 #define MVNETA_RXQ_CONFIG_REG(q)                (0x1400 + ((q) << 2))
@@ -603,6 +604,10 @@ struct mvneta_rx_queue {
 	u32 pkts_coal;
 	u32 time_coal;
 
+	/* page_pool */
+	struct page_pool *page_pool;
+	struct xdp_rxq_info xdp_rxq;
+
 	/* Virtual address of the RX buffer */
 	void  **buf_virt_addr;
 
@@ -1815,19 +1820,12 @@ static int mvneta_rx_refill(struct mvneta_port *pp,
 	dma_addr_t phys_addr;
 	struct page *page;
 
-	page = __dev_alloc_page(gfp_mask);
+	page = page_pool_alloc_pages(rxq->page_pool,
+				     gfp_mask | __GFP_NOWARN);
 	if (!page)
 		return -ENOMEM;
 
-	/* map page for use */
-	phys_addr = dma_map_page(pp->dev->dev.parent, page, 0, PAGE_SIZE,
-				 DMA_FROM_DEVICE);
-	if (unlikely(dma_mapping_error(pp->dev->dev.parent, phys_addr))) {
-		__free_page(page);
-		return -ENOMEM;
-	}
-
-	phys_addr += pp->rx_offset_correction;
+	phys_addr = page_pool_get_dma_addr(page) + pp->rx_offset_correction;
 	mvneta_rx_desc_fill(rx_desc, phys_addr, page, rxq);
 	return 0;
 }
@@ -1894,10 +1892,11 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp,
 		if (!data || !(rx_desc->buf_phys_addr))
 			continue;
 
-		dma_unmap_page(pp->dev->dev.parent, rx_desc->buf_phys_addr,
-			       PAGE_SIZE, DMA_FROM_DEVICE);
-		__free_page(data);
+		page_pool_put_page(rxq->page_pool, data, false);
 	}
+	if (xdp_rxq_info_is_reg(&rxq->xdp_rxq))
+		xdp_rxq_info_unreg(&rxq->xdp_rxq);
+	page_pool_destroy(rxq->page_pool);
 }
 
 static void
@@ -2029,8 +2028,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 				skb_add_rx_frag(rxq->skb, frag_num, page,
 						frag_offset, frag_size,
 						PAGE_SIZE);
-				dma_unmap_page(dev->dev.parent, phys_addr,
-					       PAGE_SIZE, DMA_FROM_DEVICE);
+				page_pool_release_page(rxq->page_pool, page);
 				rxq->left_size -= frag_size;
 			}
 		} else {
@@ -2060,9 +2058,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 						frag_offset, frag_size,
 						PAGE_SIZE);
 
-				dma_unmap_page(dev->dev.parent, phys_addr,
-					       PAGE_SIZE, DMA_FROM_DEVICE);
-
+				page_pool_release_page(rxq->page_pool, page);
 				rxq->left_size -= frag_size;
 			}
 		} /* Middle or Last descriptor */
@@ -2829,11 +2825,53 @@ static int mvneta_poll(struct napi_struct *napi, int budget)
 	return rx_done;
 }
 
+static int mvneta_create_page_pool(struct mvneta_port *pp,
+				   struct mvneta_rx_queue *rxq, int size)
+{
+	struct page_pool_params pp_params = {
+		.order = 0,
+		.flags = PP_FLAG_DMA_MAP,
+		.pool_size = size,
+		.nid = cpu_to_node(0),
+		.dev = pp->dev->dev.parent,
+		.dma_dir = DMA_FROM_DEVICE,
+	};
+	int err;
+
+	rxq->page_pool = page_pool_create(&pp_params);
+	if (IS_ERR(rxq->page_pool)) {
+		err = PTR_ERR(rxq->page_pool);
+		rxq->page_pool = NULL;
+		return err;
+	}
+
+	err = xdp_rxq_info_reg(&rxq->xdp_rxq, pp->dev, 0);
+	if (err < 0)
+		goto err_free_pp;
+
+	err = xdp_rxq_info_reg_mem_model(&rxq->xdp_rxq, MEM_TYPE_PAGE_POOL,
+					 rxq->page_pool);
+	if (err)
+		goto err_unregister_rxq;
+
+	return 0;
+
+err_unregister_rxq:
+	xdp_rxq_info_unreg(&rxq->xdp_rxq);
+err_free_pp:
+	page_pool_destroy(rxq->page_pool);
+	return err;
+}
+
 /* Handle rxq fill: allocates rxq skbs; called when initializing a port */
 static int mvneta_rxq_fill(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
 			   int num)
 {
-	int i;
+	int i, err;
+
+	err = mvneta_create_page_pool(pp, rxq, num);
+	if (err < 0)
+		return err;
 
 	for (i = 0; i < num; i++) {
 		memset(rxq->descs + i, 0, sizeof(struct mvneta_rx_desc));
-- 
2.21.0

[PATCH 3/7] net: mvneta: rely on build_skb in mvneta_rx_swbm poll routine

[Lorenzo Bianconi]

Refactor mvneta_rx_swbm code introducing mvneta_swbm_rx_frame and
mvneta_swbm_add_rx_fragment routines. Rely on build_skb in order to
allocate skb since the previous patch introduced buffer recycling using
the page_pool API

Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 198 ++++++++++++++------------
 1 file changed, 104 insertions(+), 94 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 8beae0e1eda7..d775fcae9353 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -323,6 +323,11 @@
 	      ETH_HLEN + ETH_FCS_LEN,			     \
 	      cache_line_size())
 
+#define MVNETA_SKB_PAD	(SKB_DATA_ALIGN(sizeof(struct skb_shared_info) + \
+			 NET_SKB_PAD))
+#define MVNETA_SKB_SIZE(len)	(SKB_DATA_ALIGN(len) + MVNETA_SKB_PAD)
+#define MVNETA_MAX_RX_BUF_SIZE	(PAGE_SIZE - MVNETA_SKB_PAD)
+
 #define IS_TSO_HEADER(txq, addr) \
 	((addr >= txq->tso_hdrs_phys) && \
 	 (addr < txq->tso_hdrs_phys + txq->size * TSO_HEADER_SIZE))
@@ -646,7 +651,6 @@ static int txq_number = 8;
 static int rxq_def;
 
 static int rx_copybreak __read_mostly = 256;
-static int rx_header_size __read_mostly = 128;
 
 /* HW BM need that each port be identify by a unique ID */
 static int global_port_id;
@@ -1941,30 +1945,102 @@ int mvneta_rx_refill_queue(struct mvneta_port *pp, struct mvneta_rx_queue *rxq)
 	return i;
 }
 
+static int
+mvneta_swbm_rx_frame(struct mvneta_port *pp,
+		     struct mvneta_rx_desc *rx_desc,
+		     struct mvneta_rx_queue *rxq,
+		     struct page *page)
+{
+	unsigned char *data = page_address(page);
+	int data_len = -MVNETA_MH_SIZE, len;
+	struct net_device *dev = pp->dev;
+	enum dma_data_direction dma_dir;
+
+	if (MVNETA_SKB_SIZE(rx_desc->data_size) > PAGE_SIZE) {
+		len = MVNETA_MAX_RX_BUF_SIZE;
+		data_len += len;
+	} else {
+		len = rx_desc->data_size;
+		data_len += len - ETH_FCS_LEN;
+	}
+
+	dma_dir = page_pool_get_dma_dir(rxq->page_pool);
+	dma_sync_single_range_for_cpu(dev->dev.parent,
+				      rx_desc->buf_phys_addr, 0,
+				      len, dma_dir);
+
+	rxq->skb = build_skb(data, PAGE_SIZE);
+	if (unlikely(!rxq->skb)) {
+		netdev_err(dev,
+			   "Can't allocate skb on queue %d\n",
+			   rxq->id);
+		dev->stats.rx_dropped++;
+		rxq->skb_alloc_err++;
+		return -ENOMEM;
+	}
+	page_pool_release_page(rxq->page_pool, page);
+
+	skb_reserve(rxq->skb, MVNETA_MH_SIZE + NET_SKB_PAD);
+	skb_put(rxq->skb, data_len);
+	mvneta_rx_csum(pp, rx_desc->status, rxq->skb);
+
+	rxq->left_size = rx_desc->data_size - len;
+	rx_desc->buf_phys_addr = 0;
+
+	return 0;
+}
+
+static void
+mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
+			    struct mvneta_rx_desc *rx_desc,
+			    struct mvneta_rx_queue *rxq,
+			    struct page *page)
+{
+	struct net_device *dev = pp->dev;
+	enum dma_data_direction dma_dir;
+	int data_len, len;
+
+	if (rxq->left_size > MVNETA_MAX_RX_BUF_SIZE) {
+		len = MVNETA_MAX_RX_BUF_SIZE;
+		data_len = len;
+	} else {
+		len = rxq->left_size;
+		data_len = len - ETH_FCS_LEN;
+	}
+	dma_dir = page_pool_get_dma_dir(rxq->page_pool);
+	dma_sync_single_range_for_cpu(dev->dev.parent,
+				      rx_desc->buf_phys_addr, 0,
+				      len, dma_dir);
+	if (data_len > 0) {
+		/* refill descriptor with new buffer later */
+		skb_add_rx_frag(rxq->skb,
+				skb_shinfo(rxq->skb)->nr_frags,
+				page, NET_SKB_PAD, data_len,
+				PAGE_SIZE);
+
+		page_pool_release_page(rxq->page_pool, page);
+		rx_desc->buf_phys_addr = 0;
+	}
+	rxq->left_size -= len;
+}
+
 /* Main rx processing when using software buffer management */
 static int mvneta_rx_swbm(struct napi_struct *napi,
 			  struct mvneta_port *pp, int budget,
 			  struct mvneta_rx_queue *rxq)
 {
-	struct net_device *dev = pp->dev;
-	int rx_todo, rx_proc;
-	int refill = 0;
-	u32 rcvd_pkts = 0;
-	u32 rcvd_bytes = 0;
+	int rcvd_pkts = 0, rcvd_bytes = 0;
+	int rx_pending, refill, done = 0;
 
 	/* Get number of received packets */
-	rx_todo = mvneta_rxq_busy_desc_num_get(pp, rxq);
-	rx_proc = 0;
+	rx_pending = mvneta_rxq_busy_desc_num_get(pp, rxq);
 
 	/* Fairness NAPI loop */
-	while ((rcvd_pkts < budget) && (rx_proc < rx_todo)) {
+	while (done < budget && done < rx_pending) {
 		struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq);
 		unsigned char *data;
 		struct page *page;
-		dma_addr_t phys_addr;
-		u32 rx_status, index;
-		int rx_bytes, skb_size, copy_size;
-		int frag_num, frag_size, frag_offset;
+		int index;
 
 		index = rx_desc - rxq->descs;
 		page = (struct page *)rxq->buf_virt_addr[index];
@@ -1972,98 +2048,33 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 		/* Prefetch header */
 		prefetch(data);
 
-		phys_addr = rx_desc->buf_phys_addr;
-		rx_status = rx_desc->status;
-		rx_proc++;
 		rxq->refill_num++;
+		done++;
+
+		if (rx_desc->status & MVNETA_RXD_FIRST_DESC) {
+			int err;
 
-		if (rx_status & MVNETA_RXD_FIRST_DESC) {
 			/* Check errors only for FIRST descriptor */
-			if (rx_status & MVNETA_RXD_ERR_SUMMARY) {
+			if (rx_desc->status & MVNETA_RXD_ERR_SUMMARY) {
 				mvneta_rx_error(pp, rx_desc);
-				dev->stats.rx_errors++;
+				pp->dev->stats.rx_errors++;
 				/* leave the descriptor untouched */
 				continue;
 			}
-			rx_bytes = rx_desc->data_size -
-				   (ETH_FCS_LEN + MVNETA_MH_SIZE);
 
-			/* Allocate small skb for each new packet */
-			skb_size = max(rx_copybreak, rx_header_size);
-			rxq->skb = netdev_alloc_skb_ip_align(dev, skb_size);
-			if (unlikely(!rxq->skb)) {
-				netdev_err(dev,
-					   "Can't allocate skb on queue %d\n",
-					   rxq->id);
-				dev->stats.rx_dropped++;
-				rxq->skb_alloc_err++;
+			err = mvneta_swbm_rx_frame(pp, rx_desc, rxq, page);
+			if (err)
 				continue;
-			}
-			copy_size = min(skb_size, rx_bytes);
-
-			/* Copy data from buffer to SKB, skip Marvell header */
-			memcpy(rxq->skb->data, data + MVNETA_MH_SIZE,
-			       copy_size);
-			skb_put(rxq->skb, copy_size);
-			rxq->left_size = rx_bytes - copy_size;
-
-			mvneta_rx_csum(pp, rx_status, rxq->skb);
-			if (rxq->left_size == 0) {
-				int size = copy_size + MVNETA_MH_SIZE;
-
-				dma_sync_single_range_for_cpu(dev->dev.parent,
-							      phys_addr, 0,
-							      size,
-							      DMA_FROM_DEVICE);
-
-				/* leave the descriptor and buffer untouched */
-			} else {
-				/* refill descriptor with new buffer later */
-				rx_desc->buf_phys_addr = 0;
-
-				frag_num = 0;
-				frag_offset = copy_size + MVNETA_MH_SIZE;
-				frag_size = min(rxq->left_size,
-						(int)(PAGE_SIZE - frag_offset));
-				skb_add_rx_frag(rxq->skb, frag_num, page,
-						frag_offset, frag_size,
-						PAGE_SIZE);
-				page_pool_release_page(rxq->page_pool, page);
-				rxq->left_size -= frag_size;
-			}
 		} else {
-			/* Middle or Last descriptor */
 			if (unlikely(!rxq->skb)) {
 				pr_debug("no skb for rx_status 0x%x\n",
-					 rx_status);
+					 rx_desc->status);
 				continue;
 			}
-			if (!rxq->left_size) {
-				/* last descriptor has only FCS */
-				/* and can be discarded */
-				dma_sync_single_range_for_cpu(dev->dev.parent,
-							      phys_addr, 0,
-							      ETH_FCS_LEN,
-							      DMA_FROM_DEVICE);
-				/* leave the descriptor and buffer untouched */
-			} else {
-				/* refill descriptor with new buffer later */
-				rx_desc->buf_phys_addr = 0;
-
-				frag_num = skb_shinfo(rxq->skb)->nr_frags;
-				frag_offset = 0;
-				frag_size = min(rxq->left_size,
-						(int)(PAGE_SIZE - frag_offset));
-				skb_add_rx_frag(rxq->skb, frag_num, page,
-						frag_offset, frag_size,
-						PAGE_SIZE);
-
-				page_pool_release_page(rxq->page_pool, page);
-				rxq->left_size -= frag_size;
-			}
+			mvneta_swbm_add_rx_fragment(pp, rx_desc, rxq, page);
 		} /* Middle or Last descriptor */
 
-		if (!(rx_status & MVNETA_RXD_LAST_DESC))
+		if (!(rx_desc->status & MVNETA_RXD_LAST_DESC))
 			/* no last descriptor this time */
 			continue;
 
@@ -2079,13 +2090,12 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 		rcvd_bytes += rxq->skb->len;
 
 		/* Linux processing */
-		rxq->skb->protocol = eth_type_trans(rxq->skb, dev);
+		rxq->skb->protocol = eth_type_trans(rxq->skb, pp->dev);
 
 		napi_gro_receive(napi, rxq->skb);
 
 		/* clean uncomplete skb pointer in queue */
 		rxq->skb = NULL;
-		rxq->left_size = 0;
 	}
 
 	mvneta_update_stats(pp, rcvd_pkts, rcvd_bytes, false);
@@ -2094,7 +2104,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 	refill = mvneta_rx_refill_queue(pp, rxq);
 
 	/* Update rxq management counters */
-	mvneta_rxq_desc_num_update(pp, rxq, rx_proc, refill);
+	mvneta_rxq_desc_num_update(pp, rxq, done, refill);
 
 	return rcvd_pkts;
 }
@@ -2945,7 +2955,7 @@ static void mvneta_rxq_hw_init(struct mvneta_port *pp,
 		/* Set Offset */
 		mvneta_rxq_offset_set(pp, rxq, 0);
 		mvneta_rxq_buf_size_set(pp, rxq, PAGE_SIZE < SZ_64K ?
-					PAGE_SIZE :
+					MVNETA_MAX_RX_BUF_SIZE :
 					MVNETA_RX_BUF_SIZE(pp->pkt_size));
 		mvneta_rxq_bm_disable(pp, rxq);
 		mvneta_rxq_fill(pp, rxq, rxq->size);
@@ -4655,7 +4665,7 @@ static int mvneta_probe(struct platform_device *pdev)
 	SET_NETDEV_DEV(dev, &pdev->dev);
 
 	pp->id = global_port_id++;
-	pp->rx_offset_correction = 0; /* not relevant for SW BM */
+	pp->rx_offset_correction = NET_SKB_PAD;
 
 	/* Obtain access to BM resources if enabled and already initialized */
 	bm_node = of_parse_phandle(dn, "buffer-manager", 0);
-- 
2.21.0

[PATCH 4/7] net: mvneta: add basic XDP support

[Lorenzo Bianconi]

Add basic XDP support to mvneta driver for devices that rely on software
buffer management. Currently supported verdicts are:
- XDP_DROP
- XDP_PASS
- XDP_REDIRECT
- XDP_ABORTED

Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 146 ++++++++++++++++++++++++--
 1 file changed, 137 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index d775fcae9353..7cbcf1b54da6 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -38,6 +38,7 @@
 #include <net/ipv6.h>
 #include <net/tso.h>
 #include <net/page_pool.h>
+#include <linux/bpf_trace.h>
 
 /* Registers */
 #define MVNETA_RXQ_CONFIG_REG(q)                (0x1400 + ((q) << 2))
@@ -323,8 +324,10 @@
 	      ETH_HLEN + ETH_FCS_LEN,			     \
 	      cache_line_size())
 
+#define MVNETA_SKB_HEADROOM	(max(XDP_PACKET_HEADROOM, NET_SKB_PAD) + \
+				 NET_IP_ALIGN)
 #define MVNETA_SKB_PAD	(SKB_DATA_ALIGN(sizeof(struct skb_shared_info) + \
-			 NET_SKB_PAD))
+			 MVNETA_SKB_HEADROOM))
 #define MVNETA_SKB_SIZE(len)	(SKB_DATA_ALIGN(len) + MVNETA_SKB_PAD)
 #define MVNETA_MAX_RX_BUF_SIZE	(PAGE_SIZE - MVNETA_SKB_PAD)
 
@@ -352,6 +355,11 @@ struct mvneta_statistic {
 #define T_REG_64	64
 #define T_SW		1
 
+#define MVNETA_XDP_PASS		BIT(0)
+#define MVNETA_XDP_CONSUMED	BIT(1)
+#define MVNETA_XDP_TX		BIT(2)
+#define MVNETA_XDP_REDIR	BIT(3)
+
 static const struct mvneta_statistic mvneta_statistics[] = {
 	{ 0x3000, T_REG_64, "good_octets_received", },
 	{ 0x3010, T_REG_32, "good_frames_received", },
@@ -431,6 +439,8 @@ struct mvneta_port {
 	u32 cause_rx_tx;
 	struct napi_struct napi;
 
+	struct bpf_prog *xdp_prog;
+
 	/* Core clock */
 	struct clk *clk;
 	/* AXI clock */
@@ -1945,16 +1955,60 @@ int mvneta_rx_refill_queue(struct mvneta_port *pp, struct mvneta_rx_queue *rxq)
 	return i;
 }
 
+static int
+mvneta_run_xdp(struct mvneta_port *pp, struct bpf_prog *prog,
+	       struct xdp_buff *xdp)
+{
+	u32 ret, act = bpf_prog_run_xdp(prog, xdp);
+
+	switch (act) {
+	case XDP_PASS:
+		ret = MVNETA_XDP_PASS;
+		break;
+	case XDP_REDIRECT: {
+		int err;
+
+		err = xdp_do_redirect(pp->dev, xdp, prog);
+		if (err) {
+			ret = MVNETA_XDP_CONSUMED;
+			xdp_return_buff(xdp);
+		} else {
+			ret = MVNETA_XDP_REDIR;
+		}
+		break;
+	}
+	default:
+		bpf_warn_invalid_xdp_action(act);
+		/* fall through */
+	case XDP_ABORTED:
+		trace_xdp_exception(pp->dev, prog, act);
+		/* fall through */
+	case XDP_DROP:
+		ret = MVNETA_XDP_CONSUMED;
+		xdp_return_buff(xdp);
+		break;
+	}
+
+	return ret;
+}
+
 static int
 mvneta_swbm_rx_frame(struct mvneta_port *pp,
 		     struct mvneta_rx_desc *rx_desc,
 		     struct mvneta_rx_queue *rxq,
-		     struct page *page)
+		     struct bpf_prog *xdp_prog,
+		     struct page *page, u32 *xdp_ret)
 {
 	unsigned char *data = page_address(page);
 	int data_len = -MVNETA_MH_SIZE, len;
 	struct net_device *dev = pp->dev;
 	enum dma_data_direction dma_dir;
+	struct xdp_buff xdp = {
+		.data_hard_start = data,
+		.data = data + MVNETA_SKB_HEADROOM + MVNETA_MH_SIZE,
+		.rxq = &rxq->xdp_rxq,
+	};
+	xdp_set_data_meta_invalid(&xdp);
 
 	if (MVNETA_SKB_SIZE(rx_desc->data_size) > PAGE_SIZE) {
 		len = MVNETA_MAX_RX_BUF_SIZE;
@@ -1963,13 +2017,29 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
 		len = rx_desc->data_size;
 		data_len += len - ETH_FCS_LEN;
 	}
+	xdp.data_end = xdp.data + data_len;
 
 	dma_dir = page_pool_get_dma_dir(rxq->page_pool);
 	dma_sync_single_range_for_cpu(dev->dev.parent,
 				      rx_desc->buf_phys_addr, 0,
 				      len, dma_dir);
 
-	rxq->skb = build_skb(data, PAGE_SIZE);
+	if (xdp_prog) {
+		u32 ret;
+
+		ret = mvneta_run_xdp(pp, xdp_prog, &xdp);
+		if (ret == MVNETA_XDP_REDIR ||
+		    ret == MVNETA_XDP_TX)
+			mvneta_update_stats(pp, 1, xdp.data_end - xdp.data,
+					    false);
+		if (ret != MVNETA_XDP_PASS) {
+			rx_desc->buf_phys_addr = 0;
+			*xdp_ret |= ret;
+			return ret;
+		}
+	}
+
+	rxq->skb = build_skb(xdp.data_hard_start, PAGE_SIZE);
 	if (unlikely(!rxq->skb)) {
 		netdev_err(dev,
 			   "Can't allocate skb on queue %d\n",
@@ -1980,8 +2050,9 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
 	}
 	page_pool_release_page(rxq->page_pool, page);
 
-	skb_reserve(rxq->skb, MVNETA_MH_SIZE + NET_SKB_PAD);
-	skb_put(rxq->skb, data_len);
+	skb_reserve(rxq->skb,
+		    xdp.data - xdp.data_hard_start);
+	skb_put(rxq->skb, xdp.data_end - xdp.data);
 	mvneta_rx_csum(pp, rx_desc->status, rxq->skb);
 
 	rxq->left_size = rx_desc->data_size - len;
@@ -2015,7 +2086,7 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
 		/* refill descriptor with new buffer later */
 		skb_add_rx_frag(rxq->skb,
 				skb_shinfo(rxq->skb)->nr_frags,
-				page, NET_SKB_PAD, data_len,
+				page, MVNETA_SKB_HEADROOM, data_len,
 				PAGE_SIZE);
 
 		page_pool_release_page(rxq->page_pool, page);
@@ -2031,10 +2102,15 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 {
 	int rcvd_pkts = 0, rcvd_bytes = 0;
 	int rx_pending, refill, done = 0;
+	struct bpf_prog *xdp_prog;
+	u32 xdp_ret = 0;
 
 	/* Get number of received packets */
 	rx_pending = mvneta_rxq_busy_desc_num_get(pp, rxq);
 
+	rcu_read_lock();
+	xdp_prog = READ_ONCE(pp->xdp_prog);
+
 	/* Fairness NAPI loop */
 	while (done < budget && done < rx_pending) {
 		struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq);
@@ -2062,7 +2138,8 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 				continue;
 			}
 
-			err = mvneta_swbm_rx_frame(pp, rx_desc, rxq, page);
+			err = mvneta_swbm_rx_frame(pp, rx_desc, rxq,
+						   xdp_prog, page, &xdp_ret);
 			if (err)
 				continue;
 		} else {
@@ -2097,6 +2174,10 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 		/* clean uncomplete skb pointer in queue */
 		rxq->skb = NULL;
 	}
+	rcu_read_unlock();
+
+	if (xdp_ret & MVNETA_XDP_REDIR)
+		xdp_do_flush_map();
 
 	mvneta_update_stats(pp, rcvd_pkts, rcvd_bytes, false);
 
@@ -2838,13 +2919,14 @@ static int mvneta_poll(struct napi_struct *napi, int budget)
 static int mvneta_create_page_pool(struct mvneta_port *pp,
 				   struct mvneta_rx_queue *rxq, int size)
 {
+	struct bpf_prog *xdp_prog = READ_ONCE(pp->xdp_prog);
 	struct page_pool_params pp_params = {
 		.order = 0,
 		.flags = PP_FLAG_DMA_MAP,
 		.pool_size = size,
 		.nid = cpu_to_node(0),
 		.dev = pp->dev->dev.parent,
-		.dma_dir = DMA_FROM_DEVICE,
+		.dma_dir = xdp_prog ? DMA_BIDIRECTIONAL : DMA_FROM_DEVICE,
 	};
 	int err;
 
@@ -3310,6 +3392,11 @@ static int mvneta_change_mtu(struct net_device *dev, int mtu)
 		mtu = ALIGN(MVNETA_RX_PKT_SIZE(mtu), 8);
 	}
 
+	if (pp->xdp_prog && mtu > MVNETA_MAX_RX_BUF_SIZE) {
+		netdev_info(dev, "Illegal MTU value %d for XDP mode\n", mtu);
+		return -EINVAL;
+	}
+
 	dev->mtu = mtu;
 
 	if (!netif_running(dev)) {
@@ -3979,6 +4066,46 @@ static int mvneta_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	return phylink_mii_ioctl(pp->phylink, ifr, cmd);
 }
 
+static int mvneta_xdp_setup(struct net_device *dev, struct bpf_prog *prog,
+			    struct netlink_ext_ack *extack)
+{
+	struct mvneta_port *pp = netdev_priv(dev);
+	struct bpf_prog *old_prog;
+
+	if (prog && dev->mtu > MVNETA_MAX_RX_BUF_SIZE) {
+		NL_SET_ERR_MSG_MOD(extack, "Jumbo frames not supported on XDP");
+		return -EOPNOTSUPP;
+	}
+
+	if (netif_running(dev))
+		mvneta_stop(dev);
+
+	old_prog = xchg(&pp->xdp_prog, prog);
+	if (old_prog)
+		bpf_prog_put(old_prog);
+
+	if (netif_running(dev))
+		mvneta_open(dev);
+
+	return 0;
+}
+
+static int mvneta_xdp(struct net_device *dev, struct netdev_bpf *xdp)
+{
+	struct mvneta_port *pp = netdev_priv(dev);
+
+	switch (xdp->command) {
+	case XDP_SETUP_PROG:
+		return mvneta_xdp_setup(dev, xdp->prog, xdp->extack);
+	case XDP_QUERY_PROG:
+		xdp->prog_id = pp->xdp_prog ? pp->xdp_prog->aux->id : 0;
+		return 0;
+	default:
+		NL_SET_ERR_MSG_MOD(xdp->extack, "unknown XDP command");
+		return -EINVAL;
+	}
+}
+
 /* Ethtool methods */
 
 /* Set link ksettings (phy address, speed) for ethtools */
@@ -4375,6 +4502,7 @@ static const struct net_device_ops mvneta_netdev_ops = {
 	.ndo_fix_features    = mvneta_fix_features,
 	.ndo_get_stats64     = mvneta_get_stats64,
 	.ndo_do_ioctl        = mvneta_ioctl,
+	.ndo_bpf	     = mvneta_xdp,
 };
 
 static const struct ethtool_ops mvneta_eth_tool_ops = {
@@ -4665,7 +4793,7 @@ static int mvneta_probe(struct platform_device *pdev)
 	SET_NETDEV_DEV(dev, &pdev->dev);
 
 	pp->id = global_port_id++;
-	pp->rx_offset_correction = NET_SKB_PAD;
+	pp->rx_offset_correction = MVNETA_SKB_HEADROOM;
 
 	/* Obtain access to BM resources if enabled and already initialized */
 	bm_node = of_parse_phandle(dn, "buffer-manager", 0);
-- 
2.21.0

[PATCH 5/7] net: mvneta: move header prefetch in mvneta_swbm_rx_frame

[Lorenzo Bianconi]

Move data buffer prefetch in mvneta_swbm_rx_frame after
dma_sync_single_range_for_cpu

Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 7cbcf1b54da6..45dcae52f34b 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2004,11 +2004,8 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
 	struct net_device *dev = pp->dev;
 	enum dma_data_direction dma_dir;
 	struct xdp_buff xdp = {
-		.data_hard_start = data,
-		.data = data + MVNETA_SKB_HEADROOM + MVNETA_MH_SIZE,
 		.rxq = &rxq->xdp_rxq,
 	};
-	xdp_set_data_meta_invalid(&xdp);
 
 	if (MVNETA_SKB_SIZE(rx_desc->data_size) > PAGE_SIZE) {
 		len = MVNETA_MAX_RX_BUF_SIZE;
@@ -2017,13 +2014,20 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
 		len = rx_desc->data_size;
 		data_len += len - ETH_FCS_LEN;
 	}
-	xdp.data_end = xdp.data + data_len;
 
 	dma_dir = page_pool_get_dma_dir(rxq->page_pool);
 	dma_sync_single_range_for_cpu(dev->dev.parent,
 				      rx_desc->buf_phys_addr, 0,
 				      len, dma_dir);
 
+	/* Prefetch header */
+	prefetch(data);
+
+	xdp.data_hard_start = data;
+	xdp.data = data + MVNETA_SKB_HEADROOM + MVNETA_MH_SIZE;
+	xdp.data_end = xdp.data + data_len;
+	xdp_set_data_meta_invalid(&xdp);
+
 	if (xdp_prog) {
 		u32 ret;
 
@@ -2114,15 +2118,11 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 	/* Fairness NAPI loop */
 	while (done < budget && done < rx_pending) {
 		struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq);
-		unsigned char *data;
 		struct page *page;
 		int index;
 
 		index = rx_desc - rxq->descs;
 		page = (struct page *)rxq->buf_virt_addr[index];
-		data = page_address(page);
-		/* Prefetch header */
-		prefetch(data);
 
 		rxq->refill_num++;
 		done++;
-- 
2.21.0

[PATCH 6/7] net: mvneta: make tx buffer array agnostic

[Lorenzo Bianconi]

Allow tx buffer array to contain both skb and xdp buffers in order to
enable xdp frame recycling adding XDP_TX verdict support

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 66 +++++++++++++++++----------
 1 file changed, 43 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 45dcae52f34b..28b35e55aa35 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -561,6 +561,20 @@ struct mvneta_rx_desc {
 };
 #endif
 
+enum mvneta_tx_buf_type {
+	MVNETA_TYPE_SKB,
+	MVNETA_TYPE_XDP_TX,
+	MVNETA_TYPE_XDP_NDO,
+};
+
+struct mvneta_tx_buf {
+	enum mvneta_tx_buf_type type;
+	union {
+		struct xdp_frame *xdpf;
+		struct sk_buff *skb;
+	};
+};
+
 struct mvneta_tx_queue {
 	/* Number of this TX queue, in the range 0-7 */
 	u8 id;
@@ -576,8 +590,8 @@ struct mvneta_tx_queue {
 	int tx_stop_threshold;
 	int tx_wake_threshold;
 
-	/* Array of transmitted skb */
-	struct sk_buff **tx_skb;
+	/* Array of transmitted buffers */
+	struct mvneta_tx_buf *buf;
 
 	/* Index of last TX DMA descriptor that was inserted */
 	int txq_put_index;
@@ -1780,14 +1794,9 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp,
 	int i;
 
 	for (i = 0; i < num; i++) {
+		struct mvneta_tx_buf *buf = &txq->buf[txq->txq_get_index];
 		struct mvneta_tx_desc *tx_desc = txq->descs +
 			txq->txq_get_index;
-		struct sk_buff *skb = txq->tx_skb[txq->txq_get_index];
-
-		if (skb) {
-			bytes_compl += skb->len;
-			pkts_compl++;
-		}
 
 		mvneta_txq_inc_get(txq);
 
@@ -1795,9 +1804,12 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp,
 			dma_unmap_single(pp->dev->dev.parent,
 					 tx_desc->buf_phys_addr,
 					 tx_desc->data_size, DMA_TO_DEVICE);
-		if (!skb)
+		if (!buf->skb)
 			continue;
-		dev_kfree_skb_any(skb);
+
+		bytes_compl += buf->skb->len;
+		pkts_compl++;
+		dev_kfree_skb_any(buf->skb);
 	}
 
 	netdev_tx_completed_queue(nq, pkts_compl, bytes_compl);
@@ -2315,16 +2327,19 @@ static inline void
 mvneta_tso_put_hdr(struct sk_buff *skb,
 		   struct mvneta_port *pp, struct mvneta_tx_queue *txq)
 {
-	struct mvneta_tx_desc *tx_desc;
 	int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
+	struct mvneta_tx_buf *buf = &txq->buf[txq->txq_put_index];
+	struct mvneta_tx_desc *tx_desc;
 
-	txq->tx_skb[txq->txq_put_index] = NULL;
 	tx_desc = mvneta_txq_next_desc_get(txq);
 	tx_desc->data_size = hdr_len;
 	tx_desc->command = mvneta_skb_tx_csum(pp, skb);
 	tx_desc->command |= MVNETA_TXD_F_DESC;
 	tx_desc->buf_phys_addr = txq->tso_hdrs_phys +
 				 txq->txq_put_index * TSO_HEADER_SIZE;
+	buf->type = MVNETA_TYPE_SKB;
+	buf->skb = NULL;
+
 	mvneta_txq_inc_put(txq);
 }
 
@@ -2333,6 +2348,7 @@ mvneta_tso_put_data(struct net_device *dev, struct mvneta_tx_queue *txq,
 		    struct sk_buff *skb, char *data, int size,
 		    bool last_tcp, bool is_last)
 {
+	struct mvneta_tx_buf *buf = &txq->buf[txq->txq_put_index];
 	struct mvneta_tx_desc *tx_desc;
 
 	tx_desc = mvneta_txq_next_desc_get(txq);
@@ -2346,7 +2362,8 @@ mvneta_tso_put_data(struct net_device *dev, struct mvneta_tx_queue *txq,
 	}
 
 	tx_desc->command = 0;
-	txq->tx_skb[txq->txq_put_index] = NULL;
+	buf->type = MVNETA_TYPE_SKB;
+	buf->skb = NULL;
 
 	if (last_tcp) {
 		/* last descriptor in the TCP packet */
@@ -2354,7 +2371,7 @@ mvneta_tso_put_data(struct net_device *dev, struct mvneta_tx_queue *txq,
 
 		/* last descriptor in SKB */
 		if (is_last)
-			txq->tx_skb[txq->txq_put_index] = skb;
+			buf->skb = skb;
 	}
 	mvneta_txq_inc_put(txq);
 	return 0;
@@ -2439,6 +2456,7 @@ static int mvneta_tx_frag_process(struct mvneta_port *pp, struct sk_buff *skb,
 	int i, nr_frags = skb_shinfo(skb)->nr_frags;
 
 	for (i = 0; i < nr_frags; i++) {
+		struct mvneta_tx_buf *buf = &txq->buf[txq->txq_put_index];
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		void *addr = skb_frag_address(frag);
 
@@ -2458,12 +2476,13 @@ static int mvneta_tx_frag_process(struct mvneta_port *pp, struct sk_buff *skb,
 		if (i == nr_frags - 1) {
 			/* Last descriptor */
 			tx_desc->command = MVNETA_TXD_L_DESC | MVNETA_TXD_Z_PAD;
-			txq->tx_skb[txq->txq_put_index] = skb;
+			buf->skb = skb;
 		} else {
 			/* Descriptor in the middle: Not First, Not Last */
 			tx_desc->command = 0;
-			txq->tx_skb[txq->txq_put_index] = NULL;
+			buf->skb = NULL;
 		}
+		buf->type = MVNETA_TYPE_SKB;
 		mvneta_txq_inc_put(txq);
 	}
 
@@ -2491,6 +2510,7 @@ static netdev_tx_t mvneta_tx(struct sk_buff *skb, struct net_device *dev)
 	struct mvneta_port *pp = netdev_priv(dev);
 	u16 txq_id = skb_get_queue_mapping(skb);
 	struct mvneta_tx_queue *txq = &pp->txqs[txq_id];
+	struct mvneta_tx_buf *buf = &txq->buf[txq->txq_put_index];
 	struct mvneta_tx_desc *tx_desc;
 	int len = skb->len;
 	int frags = 0;
@@ -2523,16 +2543,17 @@ static netdev_tx_t mvneta_tx(struct sk_buff *skb, struct net_device *dev)
 		goto out;
 	}
 
+	buf->type = MVNETA_TYPE_SKB;
 	if (frags == 1) {
 		/* First and Last descriptor */
 		tx_cmd |= MVNETA_TXD_FLZ_DESC;
 		tx_desc->command = tx_cmd;
-		txq->tx_skb[txq->txq_put_index] = skb;
+		buf->skb = skb;
 		mvneta_txq_inc_put(txq);
 	} else {
 		/* First but not Last */
 		tx_cmd |= MVNETA_TXD_F_DESC;
-		txq->tx_skb[txq->txq_put_index] = NULL;
+		buf->skb = NULL;
 		mvneta_txq_inc_put(txq);
 		tx_desc->command = tx_cmd;
 		/* Continue with other skb fragments */
@@ -3118,9 +3139,8 @@ static int mvneta_txq_sw_init(struct mvneta_port *pp,
 
 	txq->last_desc = txq->size - 1;
 
-	txq->tx_skb = kmalloc_array(txq->size, sizeof(*txq->tx_skb),
-				    GFP_KERNEL);
-	if (!txq->tx_skb) {
+	txq->buf = kmalloc_array(txq->size, sizeof(*txq->buf), GFP_KERNEL);
+	if (!txq->buf) {
 		dma_free_coherent(pp->dev->dev.parent,
 				  txq->size * MVNETA_DESC_ALIGNED_SIZE,
 				  txq->descs, txq->descs_phys);
@@ -3132,7 +3152,7 @@ static int mvneta_txq_sw_init(struct mvneta_port *pp,
 					   txq->size * TSO_HEADER_SIZE,
 					   &txq->tso_hdrs_phys, GFP_KERNEL);
 	if (!txq->tso_hdrs) {
-		kfree(txq->tx_skb);
+		kfree(txq->buf);
 		dma_free_coherent(pp->dev->dev.parent,
 				  txq->size * MVNETA_DESC_ALIGNED_SIZE,
 				  txq->descs, txq->descs_phys);
@@ -3185,7 +3205,7 @@ static void mvneta_txq_sw_deinit(struct mvneta_port *pp,
 {
 	struct netdev_queue *nq = netdev_get_tx_queue(pp->dev, txq->id);
 
-	kfree(txq->tx_skb);
+	kfree(txq->buf);
 
 	if (txq->tso_hdrs)
 		dma_free_coherent(pp->dev->dev.parent,
-- 
2.21.0

[PATCH 7/7] net: mvneta: add XDP_TX support

[Lorenzo Bianconi]

Implement XDP_TX verdict and ndo_xdp_xmit net_device_ops function
pointer

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 126 ++++++++++++++++++++++++--
 1 file changed, 119 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 28b35e55aa35..9ec97086f991 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -1800,16 +1800,19 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp,
 
 		mvneta_txq_inc_get(txq);
 
-		if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr))
+		if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr) &&
+		    buf->type != MVNETA_TYPE_XDP_TX)
 			dma_unmap_single(pp->dev->dev.parent,
 					 tx_desc->buf_phys_addr,
 					 tx_desc->data_size, DMA_TO_DEVICE);
-		if (!buf->skb)
-			continue;
-
-		bytes_compl += buf->skb->len;
-		pkts_compl++;
-		dev_kfree_skb_any(buf->skb);
+		if (buf->type == MVNETA_TYPE_SKB && buf->skb) {
+			bytes_compl += buf->skb->len;
+			pkts_compl++;
+			dev_kfree_skb_any(buf->skb);
+		} else if (buf->type == MVNETA_TYPE_XDP_TX ||
+			   buf->type == MVNETA_TYPE_XDP_NDO) {
+			xdp_return_frame(buf->xdpf);
+		}
 	}
 
 	netdev_tx_completed_queue(nq, pkts_compl, bytes_compl);
@@ -1967,6 +1970,109 @@ int mvneta_rx_refill_queue(struct mvneta_port *pp, struct mvneta_rx_queue *rxq)
 	return i;
 }
 
+static int
+mvneta_xdp_submit_frame(struct mvneta_port *pp, struct mvneta_tx_queue *txq,
+			struct xdp_frame *xdpf, bool dma_map)
+{
+	struct mvneta_tx_desc *tx_desc;
+	struct mvneta_tx_buf *buf;
+	dma_addr_t dma_addr;
+
+	if (txq->count >= txq->tx_stop_threshold)
+		return MVNETA_XDP_CONSUMED;
+
+	tx_desc = mvneta_txq_next_desc_get(txq);
+
+	buf = &txq->buf[txq->txq_put_index];
+	if (dma_map) {
+		/* ndo_xdp_xmit */
+		dma_addr = dma_map_single(pp->dev->dev.parent, xdpf->data,
+					  xdpf->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(pp->dev->dev.parent, dma_addr)) {
+			mvneta_txq_desc_put(txq);
+			return MVNETA_XDP_CONSUMED;
+		}
+		buf->type = MVNETA_TYPE_XDP_NDO;
+	} else {
+		struct page *page = virt_to_page(xdpf->data);
+
+		dma_addr = page_pool_get_dma_addr(page) +
+			   pp->rx_offset_correction + MVNETA_MH_SIZE;
+		dma_sync_single_for_device(pp->dev->dev.parent, dma_addr,
+					   xdpf->len, DMA_BIDIRECTIONAL);
+		buf->type = MVNETA_TYPE_XDP_TX;
+	}
+	buf->xdpf = xdpf;
+
+	tx_desc->command = MVNETA_TXD_FLZ_DESC;
+	tx_desc->buf_phys_addr = dma_addr;
+	tx_desc->data_size = xdpf->len;
+
+	mvneta_update_stats(pp, 1, xdpf->len, true);
+	mvneta_txq_inc_put(txq);
+	txq->pending++;
+	txq->count++;
+
+	return MVNETA_XDP_TX;
+}
+
+static int
+mvneta_xdp_xmit_back(struct mvneta_port *pp, struct xdp_buff *xdp)
+{
+	struct xdp_frame *xdpf = convert_to_xdp_frame(xdp);
+	int cpu = smp_processor_id();
+	struct mvneta_tx_queue *txq;
+	struct netdev_queue *nq;
+	u32 ret;
+
+	if (unlikely(!xdpf))
+		return MVNETA_XDP_CONSUMED;
+
+	txq = &pp->txqs[cpu % txq_number];
+	nq = netdev_get_tx_queue(pp->dev, txq->id);
+
+	__netif_tx_lock(nq, cpu);
+	ret = mvneta_xdp_submit_frame(pp, txq, xdpf, false);
+	if (ret == MVNETA_XDP_TX)
+		mvneta_txq_pend_desc_add(pp, txq, 0);
+	__netif_tx_unlock(nq);
+
+	return ret;
+}
+
+static int
+mvneta_xdp_xmit(struct net_device *dev, int num_frame,
+		struct xdp_frame **frames, u32 flags)
+{
+	struct mvneta_port *pp = netdev_priv(dev);
+	int cpu = smp_processor_id();
+	struct mvneta_tx_queue *txq;
+	struct netdev_queue *nq;
+	int i, drops = 0;
+	u32 ret;
+
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+		return -EINVAL;
+
+	txq = &pp->txqs[cpu % txq_number];
+	nq = netdev_get_tx_queue(pp->dev, txq->id);
+
+	__netif_tx_lock(nq, cpu);
+	for (i = 0; i < num_frame; i++) {
+		ret = mvneta_xdp_submit_frame(pp, txq, frames[i], true);
+		if (ret != MVNETA_XDP_TX) {
+			xdp_return_frame_rx_napi(frames[i]);
+			drops++;
+		}
+	}
+
+	if (unlikely(flags & XDP_XMIT_FLUSH))
+		mvneta_txq_pend_desc_add(pp, txq, 0);
+	__netif_tx_unlock(nq);
+
+	return num_frame - drops;
+}
+
 static int
 mvneta_run_xdp(struct mvneta_port *pp, struct bpf_prog *prog,
 	       struct xdp_buff *xdp)
@@ -1989,6 +2095,11 @@ mvneta_run_xdp(struct mvneta_port *pp, struct bpf_prog *prog,
 		}
 		break;
 	}
+	case XDP_TX:
+		ret = mvneta_xdp_xmit_back(pp, xdp);
+		if (ret != MVNETA_XDP_TX)
+			xdp_return_buff(xdp);
+		break;
 	default:
 		bpf_warn_invalid_xdp_action(act);
 		/* fall through */
@@ -4523,6 +4634,7 @@ static const struct net_device_ops mvneta_netdev_ops = {
 	.ndo_get_stats64     = mvneta_get_stats64,
 	.ndo_do_ioctl        = mvneta_ioctl,
 	.ndo_bpf	     = mvneta_xdp,
+	.ndo_xdp_xmit        = mvneta_xdp_xmit,
 };
 
 static const struct ethtool_ops mvneta_eth_tool_ops = {
-- 
2.21.0

Re: [PATCH 0/7] add XDP support to mvneta driver

[Lorenzo Bianconi]

>
> Add XDP support to mvneta driver for devices that rely on software
> buffer management. Supported verdicts are:
> - XDP_DROP
> - XDP_PASS
> - XDP_REDIRECT
> - XDP_TX
> Moreover set ndo_xdp_xmit net_device_ops function pointer in order to support
> redirecting from other device (e.g. virtio-net).
> Convert mvneta driver to page_pool API.
> This series is based on previous work done by Jesper and Ilias.
>
> Changes since RFC:
> - implement XDP_TX
> - make tx pending buffer list agnostic
> - code refactoring
> - check if device is running in mvneta_xdp_setup
>

This series is clearly intended for net-next :)

Regards,
Lorenzo

> Lorenzo Bianconi (7):
>   net: mvneta: introduce mvneta_update_stats routine
>   net: mvneta: introduce page pool API for sw buffer manager
>   net: mvneta: rely on build_skb in mvneta_rx_swbm poll routine
>   net: mvneta: add basic XDP support
>   net: mvneta: move header prefetch in mvneta_swbm_rx_frame
>   net: mvneta: make tx buffer array agnostic
>   net: mvneta: add XDP_TX support
>
>  drivers/net/ethernet/marvell/Kconfig  |   1 +
>  drivers/net/ethernet/marvell/mvneta.c | 627 +++++++++++++++++++-------
>  2 files changed, 468 insertions(+), 160 deletions(-)
>
> --
> 2.21.0
>

Re: [PATCH 2/7] net: mvneta: introduce page pool API for sw buffer manager

[Ilias Apalodimas]

Hi Lorenzo, 

On Sat, Oct 05, 2019 at 10:44:35PM +0200, Lorenzo Bianconi wrote:
> Use the page_pool api for allocations and DMA handling instead of
> __dev_alloc_page()/dma_map_page() and free_page()/dma_unmap_page().
> Pages are unmapped using page_pool_release_page before packets
> go into the network stack.
> 
> The page_pool API offers buffer recycling capabilities for XDP but
> allocates one page per packet, unless the driver splits and manages
> the allocated page.
> This is a preliminary patch to add XDP support to mvneta driver
> 
> Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  drivers/net/ethernet/marvell/Kconfig  |  1 +
>  drivers/net/ethernet/marvell/mvneta.c | 76 ++++++++++++++++++++-------
>  2 files changed, 58 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/Kconfig b/drivers/net/ethernet/marvell/Kconfig
> index fb942167ee54..3d5caea096fb 100644
> --- a/drivers/net/ethernet/marvell/Kconfig
> +++ b/drivers/net/ethernet/marvell/Kconfig
> @@ -61,6 +61,7 @@ config MVNETA
>  	depends on ARCH_MVEBU || COMPILE_TEST
>  	select MVMDIO
>  	select PHYLINK
> +	select PAGE_POOL
>  	---help---
>  	  This driver supports the network interface units in the
>  	  Marvell ARMADA XP, ARMADA 370, ARMADA 38x and
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index 128b9fded959..8beae0e1eda7 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -37,6 +37,7 @@
>  #include <net/ip.h>
>  #include <net/ipv6.h>
>  #include <net/tso.h>
> +#include <net/page_pool.h>
>  
>  /* Registers */
>  #define MVNETA_RXQ_CONFIG_REG(q)                (0x1400 + ((q) << 2))
> @@ -603,6 +604,10 @@ struct mvneta_rx_queue {
>  	u32 pkts_coal;
>  	u32 time_coal;
>  
> +	/* page_pool */
> +	struct page_pool *page_pool;
> +	struct xdp_rxq_info xdp_rxq;
> +
>  	/* Virtual address of the RX buffer */
>  	void  **buf_virt_addr;
>  
> @@ -1815,19 +1820,12 @@ static int mvneta_rx_refill(struct mvneta_port *pp,
>  	dma_addr_t phys_addr;
>  	struct page *page;
>  
> -	page = __dev_alloc_page(gfp_mask);
> +	page = page_pool_alloc_pages(rxq->page_pool,
> +				     gfp_mask | __GFP_NOWARN);
>  	if (!page)
>  		return -ENOMEM;

Is the driver syncing the buffer somewhere else? (for_device)
If not you'll have to do this here. 

On a non-cache coherent machine (and i think this one is) you may get dirty
cache lines handed to the device. Those dirty cache lines might get written back
*after* the device has DMA'ed it's data. You need to flush those first to avoid
any data corruption

>  
> -	/* map page for use */
> -	phys_addr = dma_map_page(pp->dev->dev.parent, page, 0, PAGE_SIZE,
> -				 DMA_FROM_DEVICE);
> -	if (unlikely(dma_mapping_error(pp->dev->dev.parent, phys_addr))) {
> -		__free_page(page);
> -		return -ENOMEM;
> -	}
> -
> -	phys_addr += pp->rx_offset_correction;
> +	phys_addr = page_pool_get_dma_addr(page) + pp->rx_offset_correction;
>  	mvneta_rx_desc_fill(rx_desc, phys_addr, page, rxq);
>  	return 0;
>  }
> @@ -1894,10 +1892,11 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp,
>  		if (!data || !(rx_desc->buf_phys_addr))
>  			continue;
>  
> -		dma_unmap_page(pp->dev->dev.parent, rx_desc->buf_phys_addr,
> -			       PAGE_SIZE, DMA_FROM_DEVICE);
> -		__free_page(data);
> +		page_pool_put_page(rxq->page_pool, data, false);
>  	}
> +	if (xdp_rxq_info_is_reg(&rxq->xdp_rxq))
> +		xdp_rxq_info_unreg(&rxq->xdp_rxq);
> +	page_pool_destroy(rxq->page_pool);
>  }
>  
>  static void
> @@ -2029,8 +2028,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
>  				skb_add_rx_frag(rxq->skb, frag_num, page,
>  						frag_offset, frag_size,
>  						PAGE_SIZE);
> -				dma_unmap_page(dev->dev.parent, phys_addr,
> -					       PAGE_SIZE, DMA_FROM_DEVICE);
> +				page_pool_release_page(rxq->page_pool, page);
>  				rxq->left_size -= frag_size;
>  			}
>  		} else {
> @@ -2060,9 +2058,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
>  						frag_offset, frag_size,
>  						PAGE_SIZE);
>  
> -				dma_unmap_page(dev->dev.parent, phys_addr,
> -					       PAGE_SIZE, DMA_FROM_DEVICE);
> -
> +				page_pool_release_page(rxq->page_pool, page);
>  				rxq->left_size -= frag_size;
>  			}
>  		} /* Middle or Last descriptor */
> @@ -2829,11 +2825,53 @@ static int mvneta_poll(struct napi_struct *napi, int budget)
>  	return rx_done;
>  }
>  
> +static int mvneta_create_page_pool(struct mvneta_port *pp,
> +				   struct mvneta_rx_queue *rxq, int size)
> +{
> +	struct page_pool_params pp_params = {
> +		.order = 0,
> +		.flags = PP_FLAG_DMA_MAP,
> +		.pool_size = size,
> +		.nid = cpu_to_node(0),
> +		.dev = pp->dev->dev.parent,
> +		.dma_dir = DMA_FROM_DEVICE,
> +	};
> +	int err;
> +
> +	rxq->page_pool = page_pool_create(&pp_params);
> +	if (IS_ERR(rxq->page_pool)) {
> +		err = PTR_ERR(rxq->page_pool);
> +		rxq->page_pool = NULL;
> +		return err;
> +	}
> +
> +	err = xdp_rxq_info_reg(&rxq->xdp_rxq, pp->dev, 0);
> +	if (err < 0)
> +		goto err_free_pp;
> +
> +	err = xdp_rxq_info_reg_mem_model(&rxq->xdp_rxq, MEM_TYPE_PAGE_POOL,
> +					 rxq->page_pool);
> +	if (err)
> +		goto err_unregister_rxq;
> +
> +	return 0;
> +
> +err_unregister_rxq:
> +	xdp_rxq_info_unreg(&rxq->xdp_rxq);
> +err_free_pp:
> +	page_pool_destroy(rxq->page_pool);
> +	return err;
> +}
> +
>  /* Handle rxq fill: allocates rxq skbs; called when initializing a port */
>  static int mvneta_rxq_fill(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
>  			   int num)
>  {
> -	int i;
> +	int i, err;
> +
> +	err = mvneta_create_page_pool(pp, rxq, num);
> +	if (err < 0)
> +		return err;
>  
>  	for (i = 0; i < num; i++) {
>  		memset(rxq->descs + i, 0, sizeof(struct mvneta_rx_desc));
> -- 
> 2.21.0
> 


Thanks
/Ilias

Re: [PATCH 3/7] net: mvneta: rely on build_skb in mvneta_rx_swbm poll routine

[Ilias Apalodimas]

Hi Lorenzo,

On Sat, Oct 05, 2019 at 10:44:36PM +0200, Lorenzo Bianconi wrote:
> Refactor mvneta_rx_swbm code introducing mvneta_swbm_rx_frame and
> mvneta_swbm_add_rx_fragment routines. Rely on build_skb in order to
> allocate skb since the previous patch introduced buffer recycling using
> the page_pool API
> 
> Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  drivers/net/ethernet/marvell/mvneta.c | 198 ++++++++++++++------------
>  1 file changed, 104 insertions(+), 94 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index 8beae0e1eda7..d775fcae9353 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -323,6 +323,11 @@
>  	      ETH_HLEN + ETH_FCS_LEN,			     \
>  	      cache_line_size())
>  
> +#define MVNETA_SKB_PAD	(SKB_DATA_ALIGN(sizeof(struct skb_shared_info) + \
> +			 NET_SKB_PAD))
> +#define MVNETA_SKB_SIZE(len)	(SKB_DATA_ALIGN(len) + MVNETA_SKB_PAD)
> +#define MVNETA_MAX_RX_BUF_SIZE	(PAGE_SIZE - MVNETA_SKB_PAD)
> +
>  #define IS_TSO_HEADER(txq, addr) \
>  	((addr >= txq->tso_hdrs_phys) && \
>  	 (addr < txq->tso_hdrs_phys + txq->size * TSO_HEADER_SIZE))
> @@ -646,7 +651,6 @@ static int txq_number = 8;
>  static int rxq_def;
>  
>  static int rx_copybreak __read_mostly = 256;
> -static int rx_header_size __read_mostly = 128;
>  
>  /* HW BM need that each port be identify by a unique ID */
>  static int global_port_id;
> @@ -1941,30 +1945,102 @@ int mvneta_rx_refill_queue(struct mvneta_port *pp, struct mvneta_rx_queue *rxq)
>  	return i;
>  }
>  
> +static int
> +mvneta_swbm_rx_frame(struct mvneta_port *pp,
> +		     struct mvneta_rx_desc *rx_desc,
> +		     struct mvneta_rx_queue *rxq,
> +		     struct page *page)
> +{
> +	unsigned char *data = page_address(page);
> +	int data_len = -MVNETA_MH_SIZE, len;
> +	struct net_device *dev = pp->dev;
> +	enum dma_data_direction dma_dir;
> +
> +	if (MVNETA_SKB_SIZE(rx_desc->data_size) > PAGE_SIZE) {
> +		len = MVNETA_MAX_RX_BUF_SIZE;
> +		data_len += len;
> +	} else {
> +		len = rx_desc->data_size;
> +		data_len += len - ETH_FCS_LEN;
> +	}
> +
> +	dma_dir = page_pool_get_dma_dir(rxq->page_pool);
> +	dma_sync_single_range_for_cpu(dev->dev.parent,
> +				      rx_desc->buf_phys_addr, 0,
> +				      len, dma_dir);
> +
> +	rxq->skb = build_skb(data, PAGE_SIZE);
> +	if (unlikely(!rxq->skb)) {
> +		netdev_err(dev,
> +			   "Can't allocate skb on queue %d\n",
> +			   rxq->id);
> +		dev->stats.rx_dropped++;
> +		rxq->skb_alloc_err++;
> +		return -ENOMEM;
> +	}
> +	page_pool_release_page(rxq->page_pool, page);
> +
> +	skb_reserve(rxq->skb, MVNETA_MH_SIZE + NET_SKB_PAD);
> +	skb_put(rxq->skb, data_len);
> +	mvneta_rx_csum(pp, rx_desc->status, rxq->skb);
> +
> +	rxq->left_size = rx_desc->data_size - len;
> +	rx_desc->buf_phys_addr = 0;
> +
> +	return 0;
> +}
> +
> +static void
> +mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
> +			    struct mvneta_rx_desc *rx_desc,
> +			    struct mvneta_rx_queue *rxq,
> +			    struct page *page)
> +{
> +	struct net_device *dev = pp->dev;
> +	enum dma_data_direction dma_dir;
> +	int data_len, len;
> +
> +	if (rxq->left_size > MVNETA_MAX_RX_BUF_SIZE) {
> +		len = MVNETA_MAX_RX_BUF_SIZE;
> +		data_len = len;
> +	} else {
> +		len = rxq->left_size;
> +		data_len = len - ETH_FCS_LEN;
> +	}
> +	dma_dir = page_pool_get_dma_dir(rxq->page_pool);
> +	dma_sync_single_range_for_cpu(dev->dev.parent,
> +				      rx_desc->buf_phys_addr, 0,
> +				      len, dma_dir);
> +	if (data_len > 0) {
> +		/* refill descriptor with new buffer later */
> +		skb_add_rx_frag(rxq->skb,
> +				skb_shinfo(rxq->skb)->nr_frags,
> +				page, NET_SKB_PAD, data_len,
> +				PAGE_SIZE);
> +
> +		page_pool_release_page(rxq->page_pool, page);
> +		rx_desc->buf_phys_addr = 0;
> +	}
> +	rxq->left_size -= len;
> +}
> +
>  /* Main rx processing when using software buffer management */
>  static int mvneta_rx_swbm(struct napi_struct *napi,
>  			  struct mvneta_port *pp, int budget,
>  			  struct mvneta_rx_queue *rxq)
>  {
> -	struct net_device *dev = pp->dev;
> -	int rx_todo, rx_proc;
> -	int refill = 0;
> -	u32 rcvd_pkts = 0;
> -	u32 rcvd_bytes = 0;
> +	int rcvd_pkts = 0, rcvd_bytes = 0;
> +	int rx_pending, refill, done = 0;
>  
>  	/* Get number of received packets */
> -	rx_todo = mvneta_rxq_busy_desc_num_get(pp, rxq);
> -	rx_proc = 0;
> +	rx_pending = mvneta_rxq_busy_desc_num_get(pp, rxq);
>  
>  	/* Fairness NAPI loop */
> -	while ((rcvd_pkts < budget) && (rx_proc < rx_todo)) {
> +	while (done < budget && done < rx_pending) {
>  		struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq);
>  		unsigned char *data;
>  		struct page *page;
> -		dma_addr_t phys_addr;
> -		u32 rx_status, index;
> -		int rx_bytes, skb_size, copy_size;
> -		int frag_num, frag_size, frag_offset;
> +		int index;
>  
>  		index = rx_desc - rxq->descs;
>  		page = (struct page *)rxq->buf_virt_addr[index];
> @@ -1972,98 +2048,33 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
>  		/* Prefetch header */
>  		prefetch(data);
>  
> -		phys_addr = rx_desc->buf_phys_addr;
> -		rx_status = rx_desc->status;
> -		rx_proc++;
>  		rxq->refill_num++;
> +		done++;
> +
> +		if (rx_desc->status & MVNETA_RXD_FIRST_DESC) {
> +			int err;
>  
> -		if (rx_status & MVNETA_RXD_FIRST_DESC) {
>  			/* Check errors only for FIRST descriptor */
> -			if (rx_status & MVNETA_RXD_ERR_SUMMARY) {
> +			if (rx_desc->status & MVNETA_RXD_ERR_SUMMARY) {
>  				mvneta_rx_error(pp, rx_desc);
> -				dev->stats.rx_errors++;
> +				pp->dev->stats.rx_errors++;
>  				/* leave the descriptor untouched */
>  				continue;
>  			}
> -			rx_bytes = rx_desc->data_size -
> -				   (ETH_FCS_LEN + MVNETA_MH_SIZE);
>  
> -			/* Allocate small skb for each new packet */
> -			skb_size = max(rx_copybreak, rx_header_size);
> -			rxq->skb = netdev_alloc_skb_ip_align(dev, skb_size);
> -			if (unlikely(!rxq->skb)) {
> -				netdev_err(dev,
> -					   "Can't allocate skb on queue %d\n",
> -					   rxq->id);
> -				dev->stats.rx_dropped++;
> -				rxq->skb_alloc_err++;
> +			err = mvneta_swbm_rx_frame(pp, rx_desc, rxq, page);
> +			if (err)
>  				continue;

The error is practically a build_skb failure probably due to low memory. 
I think it's better to break the loop and let the system reclaim some of it's
free memory instead of continuing to process (and allocate more skb's)

> -			}
> -			copy_size = min(skb_size, rx_bytes);
> -
> -			/* Copy data from buffer to SKB, skip Marvell header */
> -			memcpy(rxq->skb->data, data + MVNETA_MH_SIZE,
> -			       copy_size);
> -			skb_put(rxq->skb, copy_size);
> -			rxq->left_size = rx_bytes - copy_size;
> -
> -			mvneta_rx_csum(pp, rx_status, rxq->skb);
> -			if (rxq->left_size == 0) {
> -				int size = copy_size + MVNETA_MH_SIZE;
> -
> -				dma_sync_single_range_for_cpu(dev->dev.parent,
> -							      phys_addr, 0,
> -							      size,
> -							      DMA_FROM_DEVICE);
> -
> -				/* leave the descriptor and buffer untouched */
> -			} else {
> -				/* refill descriptor with new buffer later */
> -				rx_desc->buf_phys_addr = 0;
> -
> -				frag_num = 0;
> -				frag_offset = copy_size + MVNETA_MH_SIZE;
> -				frag_size = min(rxq->left_size,
> -						(int)(PAGE_SIZE - frag_offset));
> -				skb_add_rx_frag(rxq->skb, frag_num, page,
> -						frag_offset, frag_size,
> -						PAGE_SIZE);
> -				page_pool_release_page(rxq->page_pool, page);
> -				rxq->left_size -= frag_size;
> -			}
>  		} else {
> -			/* Middle or Last descriptor */
>  			if (unlikely(!rxq->skb)) {
>  				pr_debug("no skb for rx_status 0x%x\n",
> -					 rx_status);
> +					 rx_desc->status);
>  				continue;
>  			}
> -			if (!rxq->left_size) {
> -				/* last descriptor has only FCS */
> -				/* and can be discarded */
> -				dma_sync_single_range_for_cpu(dev->dev.parent,
> -							      phys_addr, 0,
> -							      ETH_FCS_LEN,
> -							      DMA_FROM_DEVICE);
> -				/* leave the descriptor and buffer untouched */
> -			} else {
> -				/* refill descriptor with new buffer later */
> -				rx_desc->buf_phys_addr = 0;
> -
> -				frag_num = skb_shinfo(rxq->skb)->nr_frags;
> -				frag_offset = 0;
> -				frag_size = min(rxq->left_size,
> -						(int)(PAGE_SIZE - frag_offset));
> -				skb_add_rx_frag(rxq->skb, frag_num, page,
> -						frag_offset, frag_size,
> -						PAGE_SIZE);
> -
> -				page_pool_release_page(rxq->page_pool, page);
> -				rxq->left_size -= frag_size;
> -			}
> +			mvneta_swbm_add_rx_fragment(pp, rx_desc, rxq, page);
>  		} /* Middle or Last descriptor */
>  
> -		if (!(rx_status & MVNETA_RXD_LAST_DESC))
> +		if (!(rx_desc->status & MVNETA_RXD_LAST_DESC))
>  			/* no last descriptor this time */
>  			continue;
>  
> @@ -2079,13 +2090,12 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
>  		rcvd_bytes += rxq->skb->len;
>  
>  		/* Linux processing */
> -		rxq->skb->protocol = eth_type_trans(rxq->skb, dev);
> +		rxq->skb->protocol = eth_type_trans(rxq->skb, pp->dev);
>  
>  		napi_gro_receive(napi, rxq->skb);
>  
>  		/* clean uncomplete skb pointer in queue */
>  		rxq->skb = NULL;
> -		rxq->left_size = 0;
>  	}
>  
>  	mvneta_update_stats(pp, rcvd_pkts, rcvd_bytes, false);
> @@ -2094,7 +2104,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
>  	refill = mvneta_rx_refill_queue(pp, rxq);
>  
>  	/* Update rxq management counters */
> -	mvneta_rxq_desc_num_update(pp, rxq, rx_proc, refill);
> +	mvneta_rxq_desc_num_update(pp, rxq, done, refill);
>  
>  	return rcvd_pkts;
>  }
> @@ -2945,7 +2955,7 @@ static void mvneta_rxq_hw_init(struct mvneta_port *pp,
>  		/* Set Offset */
>  		mvneta_rxq_offset_set(pp, rxq, 0);
>  		mvneta_rxq_buf_size_set(pp, rxq, PAGE_SIZE < SZ_64K ?
> -					PAGE_SIZE :
> +					MVNETA_MAX_RX_BUF_SIZE :
>  					MVNETA_RX_BUF_SIZE(pp->pkt_size));
>  		mvneta_rxq_bm_disable(pp, rxq);
>  		mvneta_rxq_fill(pp, rxq, rxq->size);
> @@ -4655,7 +4665,7 @@ static int mvneta_probe(struct platform_device *pdev)
>  	SET_NETDEV_DEV(dev, &pdev->dev);
>  
>  	pp->id = global_port_id++;
> -	pp->rx_offset_correction = 0; /* not relevant for SW BM */
> +	pp->rx_offset_correction = NET_SKB_PAD;
>  
>  	/* Obtain access to BM resources if enabled and already initialized */
>  	bm_node = of_parse_phandle(dn, "buffer-manager", 0);
> -- 
> 2.21.0
> 

Regards
/Ilias

Re: [PATCH 2/7] net: mvneta: introduce page pool API for sw buffer manager

[Lorenzo Bianconi]

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> Hi Lorenzo, 
> 

Hi Ilias,

> On Sat, Oct 05, 2019 at 10:44:35PM +0200, Lorenzo Bianconi wrote:
> > Use the page_pool api for allocations and DMA handling instead of
> > __dev_alloc_page()/dma_map_page() and free_page()/dma_unmap_page().
> > Pages are unmapped using page_pool_release_page before packets
> > go into the network stack.
> > 
> > The page_pool API offers buffer recycling capabilities for XDP but
> > allocates one page per packet, unless the driver splits and manages
> > the allocated page.
> > This is a preliminary patch to add XDP support to mvneta driver
> > 
> > Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  drivers/net/ethernet/marvell/Kconfig  |  1 +
> >  drivers/net/ethernet/marvell/mvneta.c | 76 ++++++++++++++++++++-------
> >  2 files changed, 58 insertions(+), 19 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/marvell/Kconfig b/drivers/net/ethernet/marvell/Kconfig
> > index fb942167ee54..3d5caea096fb 100644
> > --- a/drivers/net/ethernet/marvell/Kconfig
> > +++ b/drivers/net/ethernet/marvell/Kconfig
> > @@ -61,6 +61,7 @@ config MVNETA
> >  	depends on ARCH_MVEBU || COMPILE_TEST
> >  	select MVMDIO
> >  	select PHYLINK
> > +	select PAGE_POOL
> >  	---help---
> >  	  This driver supports the network interface units in the
> >  	  Marvell ARMADA XP, ARMADA 370, ARMADA 38x and
> > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> > index 128b9fded959..8beae0e1eda7 100644
> > --- a/drivers/net/ethernet/marvell/mvneta.c
> > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > @@ -37,6 +37,7 @@
> >  #include <net/ip.h>
> >  #include <net/ipv6.h>
> >  #include <net/tso.h>
> > +#include <net/page_pool.h>
> >  
> >  /* Registers */
> >  #define MVNETA_RXQ_CONFIG_REG(q)                (0x1400 + ((q) << 2))
> > @@ -603,6 +604,10 @@ struct mvneta_rx_queue {
> >  	u32 pkts_coal;
> >  	u32 time_coal;
> >  
> > +	/* page_pool */
> > +	struct page_pool *page_pool;
> > +	struct xdp_rxq_info xdp_rxq;
> > +
> >  	/* Virtual address of the RX buffer */
> >  	void  **buf_virt_addr;
> >  
> > @@ -1815,19 +1820,12 @@ static int mvneta_rx_refill(struct mvneta_port *pp,
> >  	dma_addr_t phys_addr;
> >  	struct page *page;
> >  
> > -	page = __dev_alloc_page(gfp_mask);
> > +	page = page_pool_alloc_pages(rxq->page_pool,
> > +				     gfp_mask | __GFP_NOWARN);
> >  	if (!page)
> >  		return -ENOMEM;
> 
> Is the driver syncing the buffer somewhere else? (for_device)
> If not you'll have to do this here. 

ack, I will add a dma_sync_to_device() in v2, thx for the hint :)

> 
> On a non-cache coherent machine (and i think this one is) you may get dirty
> cache lines handed to the device. Those dirty cache lines might get written back
> *after* the device has DMA'ed it's data. You need to flush those first to avoid
> any data corruption

Right.

Regards,
Lorenzo

> 
> >  
> > -	/* map page for use */
> > -	phys_addr = dma_map_page(pp->dev->dev.parent, page, 0, PAGE_SIZE,
> > -				 DMA_FROM_DEVICE);
> > -	if (unlikely(dma_mapping_error(pp->dev->dev.parent, phys_addr))) {
> > -		__free_page(page);
> > -		return -ENOMEM;
> > -	}
> > -
> > -	phys_addr += pp->rx_offset_correction;
> > +	phys_addr = page_pool_get_dma_addr(page) + pp->rx_offset_correction;
> >  	mvneta_rx_desc_fill(rx_desc, phys_addr, page, rxq);
> >  	return 0;
> >  }
> > @@ -1894,10 +1892,11 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp,
> >  		if (!data || !(rx_desc->buf_phys_addr))
> >  			continue;
> >  
> > -		dma_unmap_page(pp->dev->dev.parent, rx_desc->buf_phys_addr,
> > -			       PAGE_SIZE, DMA_FROM_DEVICE);
> > -		__free_page(data);
> > +		page_pool_put_page(rxq->page_pool, data, false);
> >  	}
> > +	if (xdp_rxq_info_is_reg(&rxq->xdp_rxq))
> > +		xdp_rxq_info_unreg(&rxq->xdp_rxq);
> > +	page_pool_destroy(rxq->page_pool);
> >  }
> >  
> >  static void
> > @@ -2029,8 +2028,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
> >  				skb_add_rx_frag(rxq->skb, frag_num, page,
> >  						frag_offset, frag_size,
> >  						PAGE_SIZE);
> > -				dma_unmap_page(dev->dev.parent, phys_addr,
> > -					       PAGE_SIZE, DMA_FROM_DEVICE);
> > +				page_pool_release_page(rxq->page_pool, page);
> >  				rxq->left_size -= frag_size;
> >  			}
> >  		} else {
> > @@ -2060,9 +2058,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
> >  						frag_offset, frag_size,
> >  						PAGE_SIZE);
> >  
> > -				dma_unmap_page(dev->dev.parent, phys_addr,
> > -					       PAGE_SIZE, DMA_FROM_DEVICE);
> > -
> > +				page_pool_release_page(rxq->page_pool, page);
> >  				rxq->left_size -= frag_size;
> >  			}
> >  		} /* Middle or Last descriptor */
> > @@ -2829,11 +2825,53 @@ static int mvneta_poll(struct napi_struct *napi, int budget)
> >  	return rx_done;
> >  }
> >  
> > +static int mvneta_create_page_pool(struct mvneta_port *pp,
> > +				   struct mvneta_rx_queue *rxq, int size)
> > +{
> > +	struct page_pool_params pp_params = {
> > +		.order = 0,
> > +		.flags = PP_FLAG_DMA_MAP,
> > +		.pool_size = size,
> > +		.nid = cpu_to_node(0),
> > +		.dev = pp->dev->dev.parent,
> > +		.dma_dir = DMA_FROM_DEVICE,
> > +	};
> > +	int err;
> > +
> > +	rxq->page_pool = page_pool_create(&pp_params);
> > +	if (IS_ERR(rxq->page_pool)) {
> > +		err = PTR_ERR(rxq->page_pool);
> > +		rxq->page_pool = NULL;
> > +		return err;
> > +	}
> > +
> > +	err = xdp_rxq_info_reg(&rxq->xdp_rxq, pp->dev, 0);
> > +	if (err < 0)
> > +		goto err_free_pp;
> > +
> > +	err = xdp_rxq_info_reg_mem_model(&rxq->xdp_rxq, MEM_TYPE_PAGE_POOL,
> > +					 rxq->page_pool);
> > +	if (err)
> > +		goto err_unregister_rxq;
> > +
> > +	return 0;
> > +
> > +err_unregister_rxq:
> > +	xdp_rxq_info_unreg(&rxq->xdp_rxq);
> > +err_free_pp:
> > +	page_pool_destroy(rxq->page_pool);
> > +	return err;
> > +}
> > +
> >  /* Handle rxq fill: allocates rxq skbs; called when initializing a port */
> >  static int mvneta_rxq_fill(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
> >  			   int num)
> >  {
> > -	int i;
> > +	int i, err;
> > +
> > +	err = mvneta_create_page_pool(pp, rxq, num);
> > +	if (err < 0)
> > +		return err;
> >  
> >  	for (i = 0; i < num; i++) {
> >  		memset(rxq->descs + i, 0, sizeof(struct mvneta_rx_desc));
> > -- 
> > 2.21.0
> > 
> 
> 
> Thanks
> /Ilias

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