[PATCH 0/4] igb: Add support for AF_XDP zero-copy

[PATCH 0/4] igb: Add support for AF_XDP zero-copy

[Sriram Yagnaraman]

Disclaimer: My first patches to Intel drivers, implemented AF_XDP
zero-copy feature which seemed to be missing for igb. Not sure if it was
a conscious choice to not spend time implementing this for older
devices, nevertheless I send them to the list for review.

The first couple of patches adds helper funcctions to prepare for AF_XDP
zero-copy support which comes in the last couple of patches, one each
for Rx and TX paths.

Sriram Yagnaraman (4):
  igb: prepare for AF_XDP zero-copy support
  igb: Introduce txrx ring enable/disable functions
  igb: add AF_XDP zero-copy Rx support
  igb: add AF_XDP zero-copy Tx support

 drivers/net/ethernet/intel/igb/Makefile   |   2 +-
 drivers/net/ethernet/intel/igb/igb.h      |  52 ++-
 drivers/net/ethernet/intel/igb/igb_main.c | 178 +++++++--
 drivers/net/ethernet/intel/igb/igb_xsk.c  | 434 ++++++++++++++++++++++
 4 files changed, 633 insertions(+), 33 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/igb/igb_xsk.c

-- 
2.34.1

[PATCH 1/4] igb: prepare for AF_XDP zero-copy support

[Sriram Yagnaraman]

Remove static qualifiers on the following functions to be able to call
from XSK specific file that is added in the later patches
- igb_xdp_tx_queue_mapping
- igb_xdp_ring_update_tail
- igb_run_xdp
- igb_process_skb_fields

Introduce igb_xdp_is_enabled() to check if an XDP program is assigned to
the device.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
---
 drivers/net/ethernet/intel/igb/igb.h      | 13 +++++++++++++
 drivers/net/ethernet/intel/igb/igb_main.c | 23 ++++++++++++-----------
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 015b78144114..94440af6cf4b 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -718,6 +718,8 @@ extern char igb_driver_name[];
 int igb_xmit_xdp_ring(struct igb_adapter *adapter,
 		      struct igb_ring *ring,
 		      struct xdp_frame *xdpf);
+struct igb_ring *igb_xdp_tx_queue_mapping(struct igb_adapter *adapter);
+void igb_xdp_ring_update_tail(struct igb_ring *ring);
 int igb_open(struct net_device *netdev);
 int igb_close(struct net_device *netdev);
 int igb_up(struct igb_adapter *);
@@ -737,6 +739,12 @@ void igb_setup_tctl(struct igb_adapter *);
 void igb_setup_rctl(struct igb_adapter *);
 void igb_setup_srrctl(struct igb_adapter *, struct igb_ring *);
 netdev_tx_t igb_xmit_frame_ring(struct sk_buff *, struct igb_ring *);
+struct sk_buff *igb_run_xdp(struct igb_adapter *adapter,
+			    struct igb_ring *rx_ring,
+			    struct xdp_buff *xdp);
+void igb_process_skb_fields(struct igb_ring *rx_ring,
+			    union e1000_adv_rx_desc *rx_desc,
+			    struct sk_buff *skb);
 void igb_alloc_rx_buffers(struct igb_ring *, u16);
 void igb_update_stats(struct igb_adapter *);
 bool igb_has_link(struct igb_adapter *adapter);
@@ -797,6 +805,11 @@ static inline struct netdev_queue *txring_txq(const struct igb_ring *tx_ring)
 	return netdev_get_tx_queue(tx_ring->netdev, tx_ring->queue_index);
 }
 
+static inline bool igb_xdp_is_enabled(struct igb_adapter *adapter)
+{
+	return !!adapter->xdp_prog;
+}
+
 int igb_add_filter(struct igb_adapter *adapter,
 		   struct igb_nfc_filter *input);
 int igb_erase_filter(struct igb_adapter *adapter,
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 9a2561409b06..dadc3d423cfd 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2939,7 +2939,8 @@ static int igb_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 	}
 }
 
-static void igb_xdp_ring_update_tail(struct igb_ring *ring)
+/* This function assumes __netif_tx_lock is held by the caller. */
+void igb_xdp_ring_update_tail(struct igb_ring *ring)
 {
 	/* Force memory writes to complete before letting h/w know there
 	 * are new descriptors to fetch.
@@ -2948,7 +2949,7 @@ static void igb_xdp_ring_update_tail(struct igb_ring *ring)
 	writel(ring->next_to_use, ring->tail);
 }
 
-static struct igb_ring *igb_xdp_tx_queue_mapping(struct igb_adapter *adapter)
+struct igb_ring *igb_xdp_tx_queue_mapping(struct igb_adapter *adapter)
 {
 	unsigned int r_idx = smp_processor_id();
 
@@ -3025,11 +3026,11 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
 		nxmit++;
 	}
 
-	__netif_tx_unlock(nq);
-
 	if (unlikely(flags & XDP_XMIT_FLUSH))
 		igb_xdp_ring_update_tail(tx_ring);
 
+	__netif_tx_unlock(nq);
+
 	return nxmit;
 }
 
@@ -6631,7 +6632,7 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	int max_frame = new_mtu + IGB_ETH_PKT_HDR_PAD;
 
-	if (adapter->xdp_prog) {
+	if (igb_xdp_is_enabled(adapter)) {
 		int i;
 
 		for (i = 0; i < adapter->num_rx_queues; i++) {
@@ -8600,9 +8601,9 @@ static struct sk_buff *igb_build_skb(struct igb_ring *rx_ring,
 	return skb;
 }
 
-static struct sk_buff *igb_run_xdp(struct igb_adapter *adapter,
-				   struct igb_ring *rx_ring,
-				   struct xdp_buff *xdp)
+struct sk_buff *igb_run_xdp(struct igb_adapter *adapter,
+			    struct igb_ring *rx_ring,
+			    struct xdp_buff *xdp)
 {
 	int err, result = IGB_XDP_PASS;
 	struct bpf_prog *xdp_prog;
@@ -8798,9 +8799,9 @@ static bool igb_cleanup_headers(struct igb_ring *rx_ring,
  *  order to populate the hash, checksum, VLAN, timestamp, protocol, and
  *  other fields within the skb.
  **/
-static void igb_process_skb_fields(struct igb_ring *rx_ring,
-				   union e1000_adv_rx_desc *rx_desc,
-				   struct sk_buff *skb)
+void igb_process_skb_fields(struct igb_ring *rx_ring,
+			    union e1000_adv_rx_desc *rx_desc,
+			    struct sk_buff *skb)
 {
 	struct net_device *dev = rx_ring->netdev;
 
-- 
2.34.1

[PATCH 2/4] igb: Introduce txrx ring enable/disable functions

[Sriram Yagnaraman]

Add enable/disable functions for TX and RX rings, will be used in later
patches when AF_XDP zero-copy support is added.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
---
 drivers/net/ethernet/intel/igb/igb.h      |  5 ++-
 drivers/net/ethernet/intel/igb/igb_main.c | 41 +++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 94440af6cf4b..5fa011c6ef2f 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -384,7 +384,8 @@ enum e1000_ring_flags_t {
 	IGB_RING_FLAG_RX_SCTP_CSUM,
 	IGB_RING_FLAG_RX_LB_VLAN_BSWAP,
 	IGB_RING_FLAG_TX_CTX_IDX,
-	IGB_RING_FLAG_TX_DETECT_HANG
+	IGB_RING_FLAG_TX_DETECT_HANG,
+	IGB_RING_FLAG_TX_DISABLED
 };
 
 #define ring_uses_large_buffer(ring) \
@@ -735,6 +736,8 @@ void igb_free_tx_resources(struct igb_ring *);
 void igb_free_rx_resources(struct igb_ring *);
 void igb_configure_tx_ring(struct igb_adapter *, struct igb_ring *);
 void igb_configure_rx_ring(struct igb_adapter *, struct igb_ring *);
+void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid);
+void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid);
 void igb_setup_tctl(struct igb_adapter *);
 void igb_setup_rctl(struct igb_adapter *);
 void igb_setup_srrctl(struct igb_adapter *, struct igb_ring *);
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index dadc3d423cfd..391c0eb136d9 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4856,6 +4856,47 @@ static void igb_configure_rx(struct igb_adapter *adapter)
 	}
 }
 
+void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid)
+{
+	struct e1000_hw *hw = &adapter->hw;
+	struct igb_ring *tx_ring = adapter->tx_ring[qid];
+	struct igb_ring *rx_ring = adapter->rx_ring[qid];
+
+	set_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
+
+	wr32(E1000_TXDCTL(tx_ring->reg_idx), 0);
+	wr32(E1000_RXDCTL(rx_ring->reg_idx), 0);
+
+	/* Rx/Tx share the same napi context. */
+	napi_disable(&rx_ring->q_vector->napi);
+
+	igb_clean_tx_ring(tx_ring);
+	igb_clean_rx_ring(rx_ring);
+
+	memset(&rx_ring->rx_stats, 0, sizeof(rx_ring->rx_stats));
+	memset(&tx_ring->tx_stats, 0, sizeof(tx_ring->tx_stats));
+}
+
+void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid)
+{
+	struct igb_ring *tx_ring = adapter->tx_ring[qid];
+	struct igb_ring *rx_ring = adapter->rx_ring[qid];
+
+	/* Rx/Tx share the same napi context. */
+	napi_enable(&rx_ring->q_vector->napi);
+
+	igb_configure_tx_ring(adapter, tx_ring);
+	igb_configure_rx_ring(adapter, rx_ring);
+
+	/* call igb_desc_unused which always leaves
+	 * at least 1 descriptor unused to make sure
+	 * next_to_use != next_to_clean
+	 */
+	igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));
+
+	clear_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
+}
+
 /**
  *  igb_free_tx_resources - Free Tx Resources per Queue
  *  @tx_ring: Tx descriptor ring for a specific queue
-- 
2.34.1

Re: [PATCH 2/4] igb: Introduce txrx ring enable/disable functions

[Maciej Fijalkowski]

On Tue, Jul 04, 2023 at 11:59:13AM +0200, Sriram Yagnaraman wrote:
> Add enable/disable functions for TX and RX rings, will be used in later
> patches when AF_XDP zero-copy support is added.
> 
> Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
> ---
>  drivers/net/ethernet/intel/igb/igb.h      |  5 ++-
>  drivers/net/ethernet/intel/igb/igb_main.c | 41 +++++++++++++++++++++++
>  2 files changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
> index 94440af6cf4b..5fa011c6ef2f 100644
> --- a/drivers/net/ethernet/intel/igb/igb.h
> +++ b/drivers/net/ethernet/intel/igb/igb.h
> @@ -384,7 +384,8 @@ enum e1000_ring_flags_t {
>  	IGB_RING_FLAG_RX_SCTP_CSUM,
>  	IGB_RING_FLAG_RX_LB_VLAN_BSWAP,
>  	IGB_RING_FLAG_TX_CTX_IDX,
> -	IGB_RING_FLAG_TX_DETECT_HANG
> +	IGB_RING_FLAG_TX_DETECT_HANG,
> +	IGB_RING_FLAG_TX_DISABLED
>  };
>  
>  #define ring_uses_large_buffer(ring) \
> @@ -735,6 +736,8 @@ void igb_free_tx_resources(struct igb_ring *);
>  void igb_free_rx_resources(struct igb_ring *);
>  void igb_configure_tx_ring(struct igb_adapter *, struct igb_ring *);
>  void igb_configure_rx_ring(struct igb_adapter *, struct igb_ring *);
> +void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid);
> +void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid);
>  void igb_setup_tctl(struct igb_adapter *);
>  void igb_setup_rctl(struct igb_adapter *);
>  void igb_setup_srrctl(struct igb_adapter *, struct igb_ring *);
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index dadc3d423cfd..391c0eb136d9 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -4856,6 +4856,47 @@ static void igb_configure_rx(struct igb_adapter *adapter)
>  	}
>  }
>  
> +void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid)

they could be static funcs defined in igb_xsk.c i believe? I'll review the
rest after you address the things I have requested on cover letter
response.

> +{
> +	struct e1000_hw *hw = &adapter->hw;
> +	struct igb_ring *tx_ring = adapter->tx_ring[qid];
> +	struct igb_ring *rx_ring = adapter->rx_ring[qid];
> +
> +	set_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
> +
> +	wr32(E1000_TXDCTL(tx_ring->reg_idx), 0);
> +	wr32(E1000_RXDCTL(rx_ring->reg_idx), 0);
> +
> +	/* Rx/Tx share the same napi context. */
> +	napi_disable(&rx_ring->q_vector->napi);
> +
> +	igb_clean_tx_ring(tx_ring);
> +	igb_clean_rx_ring(rx_ring);
> +
> +	memset(&rx_ring->rx_stats, 0, sizeof(rx_ring->rx_stats));
> +	memset(&tx_ring->tx_stats, 0, sizeof(tx_ring->tx_stats));
> +}
> +
> +void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid)
> +{
> +	struct igb_ring *tx_ring = adapter->tx_ring[qid];
> +	struct igb_ring *rx_ring = adapter->rx_ring[qid];
> +
> +	/* Rx/Tx share the same napi context. */
> +	napi_enable(&rx_ring->q_vector->napi);
> +
> +	igb_configure_tx_ring(adapter, tx_ring);
> +	igb_configure_rx_ring(adapter, rx_ring);
> +
> +	/* call igb_desc_unused which always leaves
> +	 * at least 1 descriptor unused to make sure
> +	 * next_to_use != next_to_clean
> +	 */
> +	igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));
> +
> +	clear_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
> +}
> +
>  /**
>   *  igb_free_tx_resources - Free Tx Resources per Queue
>   *  @tx_ring: Tx descriptor ring for a specific queue
> -- 
> 2.34.1
> 
> 

[PATCH 3/4] igb: add AF_XDP zero-copy Rx support

[Sriram Yagnaraman]

Add support for AF_XDP zero-copy receive path.

Add IGB_RING_FLAG_AF_XDP_ZC ring flag to indicate that a ring has AF_XDP
zero-copy support. This flag is used in igb_configure_rx_ring to
register XSK_BUFF_POOL (if zero-copy is enabled) memory model or the
default PAGE_SHARED model otherwise.

When AF_XDP zero-copy is enabled, the rx buffers are allocated from the
xsk buff pool using igb_alloc_rx_buffers_zc.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
---
 drivers/net/ethernet/intel/igb/Makefile   |   2 +-
 drivers/net/ethernet/intel/igb/igb.h      |  34 +-
 drivers/net/ethernet/intel/igb/igb_main.c |  72 ++++-
 drivers/net/ethernet/intel/igb/igb_xsk.c  | 373 ++++++++++++++++++++++
 4 files changed, 463 insertions(+), 18 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/igb/igb_xsk.c

diff --git a/drivers/net/ethernet/intel/igb/Makefile b/drivers/net/ethernet/intel/igb/Makefile
index 394c1e0656b9..86d25dba507d 100644
--- a/drivers/net/ethernet/intel/igb/Makefile
+++ b/drivers/net/ethernet/intel/igb/Makefile
@@ -8,4 +8,4 @@ obj-$(CONFIG_IGB) += igb.o
 
 igb-objs := igb_main.o igb_ethtool.o e1000_82575.o \
 	    e1000_mac.o e1000_nvm.o e1000_phy.o e1000_mbx.o \
-	    e1000_i210.o igb_ptp.o igb_hwmon.o
+	    e1000_i210.o igb_ptp.o igb_hwmon.o igb_xsk.o
diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 5fa011c6ef2f..4f474d7338b5 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -20,6 +20,7 @@
 #include <linux/mdio.h>
 
 #include <net/xdp.h>
+#include <net/xdp_sock_drv.h>
 
 struct igb_adapter;
 
@@ -86,6 +87,7 @@ struct igb_adapter;
 #define IGB_XDP_CONSUMED	BIT(0)
 #define IGB_XDP_TX		BIT(1)
 #define IGB_XDP_REDIR		BIT(2)
+#define IGB_XDP_EXIT		BIT(3)
 
 struct vf_data_storage {
 	unsigned char vf_mac_addresses[ETH_ALEN];
@@ -278,14 +280,23 @@ struct igb_tx_buffer {
 };
 
 struct igb_rx_buffer {
-	dma_addr_t dma;
-	struct page *page;
+	union {
+		struct {
+			struct sk_buff *skb;
+			dma_addr_t dma;
+			struct page *page;
 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
-	__u32 page_offset;
+		__u32 page_offset;
 #else
-	__u16 page_offset;
+		__u16 page_offset;
 #endif
-	__u16 pagecnt_bias;
+			__u16 pagecnt_bias;
+		};
+		struct {
+			struct xdp_buff *xdp;
+		};
+	};
+
 };
 
 struct igb_tx_queue_stats {
@@ -357,6 +368,7 @@ struct igb_ring {
 		};
 	};
 	struct xdp_rxq_info xdp_rxq;
+	struct xsk_buff_pool *xsk_pool;
 } ____cacheline_internodealigned_in_smp;
 
 struct igb_q_vector {
@@ -385,7 +397,8 @@ enum e1000_ring_flags_t {
 	IGB_RING_FLAG_RX_LB_VLAN_BSWAP,
 	IGB_RING_FLAG_TX_CTX_IDX,
 	IGB_RING_FLAG_TX_DETECT_HANG,
-	IGB_RING_FLAG_TX_DISABLED
+	IGB_RING_FLAG_TX_DISABLED,
+	IGB_RING_FLAG_AF_XDP_ZC
 };
 
 #define ring_uses_large_buffer(ring) \
@@ -823,4 +836,13 @@ int igb_add_mac_steering_filter(struct igb_adapter *adapter,
 int igb_del_mac_steering_filter(struct igb_adapter *adapter,
 				const u8 *addr, u8 queue, u8 flags);
 
+struct xsk_buff_pool *igb_xsk_pool(struct igb_adapter *adapter,
+				   struct igb_ring *ring);
+int igb_xsk_pool_setup(struct igb_adapter *adapter,
+		       struct xsk_buff_pool *pool,
+		       u16 qid);
+bool igb_alloc_rx_buffers_zc(struct igb_ring *rx_ring, u16 count);
+int igb_clean_rx_irq_zc(struct igb_q_vector *q_vector, const int budget);
+int igb_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags);
+
 #endif /* _IGB_H_ */
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 391c0eb136d9..f4dbb75d6eac 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2013,7 +2013,9 @@ static void igb_configure(struct igb_adapter *adapter)
 	 */
 	for (i = 0; i < adapter->num_rx_queues; i++) {
 		struct igb_ring *ring = adapter->rx_ring[i];
-		igb_alloc_rx_buffers(ring, igb_desc_unused(ring));
+		ring->xsk_pool ?
+			igb_alloc_rx_buffers_zc(ring, igb_desc_unused(ring)) :
+			igb_alloc_rx_buffers(ring, igb_desc_unused(ring));
 	}
 }
 
@@ -2931,9 +2933,14 @@ static int igb_xdp_setup(struct net_device *dev, struct netdev_bpf *bpf)
 
 static int igb_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 {
+	struct igb_adapter *adapter = netdev_priv(dev);
+
 	switch (xdp->command) {
 	case XDP_SETUP_PROG:
 		return igb_xdp_setup(dev, xdp);
+	case XDP_SETUP_XSK_POOL:
+		return igb_xsk_pool_setup(adapter, xdp->xsk.pool,
+					  xdp->xsk.queue_id);
 	default:
 		return -EINVAL;
 	}
@@ -3010,6 +3017,9 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
 	if (unlikely(!tx_ring))
 		return -ENXIO;
 
+	if (unlikely(test_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags)))
+		return -ENXIO;
+
 	nq = txring_txq(tx_ring);
 	__netif_tx_lock(nq, cpu);
 
@@ -3060,6 +3070,7 @@ static const struct net_device_ops igb_netdev_ops = {
 	.ndo_setup_tc		= igb_setup_tc,
 	.ndo_bpf		= igb_xdp,
 	.ndo_xdp_xmit		= igb_xdp_xmit,
+	.ndo_xsk_wakeup         = igb_xsk_wakeup,
 };
 
 /**
@@ -3356,7 +3367,8 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	netdev->priv_flags |= IFF_SUPP_NOFCS;
 
 	netdev->priv_flags |= IFF_UNICAST_FLT;
-	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT;
+	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
+			       NETDEV_XDP_ACT_XSK_ZEROCOPY;
 
 	/* MTU range: 68 - 9216 */
 	netdev->min_mtu = ETH_MIN_MTU;
@@ -4734,12 +4746,17 @@ void igb_setup_srrctl(struct igb_adapter *adapter, struct igb_ring *ring)
 	struct e1000_hw *hw = &adapter->hw;
 	int reg_idx = ring->reg_idx;
 	u32 srrctl = 0;
+	u32 buf_size;
 
-	srrctl = IGB_RX_HDR_LEN << E1000_SRRCTL_BSIZEHDRSIZE_SHIFT;
-	if (ring_uses_large_buffer(ring))
-		srrctl |= IGB_RXBUFFER_3072 >> E1000_SRRCTL_BSIZEPKT_SHIFT;
+	if (ring->xsk_pool)
+		buf_size = xsk_pool_get_rx_frame_size(ring->xsk_pool);
+	else if (ring_uses_large_buffer(ring))
+		buf_size = IGB_RXBUFFER_3072;
 	else
-		srrctl |= IGB_RXBUFFER_2048 >> E1000_SRRCTL_BSIZEPKT_SHIFT;
+		buf_size = IGB_RXBUFFER_2048;
+
+	srrctl = IGB_RX_HDR_LEN << E1000_SRRCTL_BSIZEHDRSIZE_SHIFT;
+	srrctl |= buf_size >> E1000_SRRCTL_BSIZEPKT_SHIFT;
 	srrctl |= E1000_SRRCTL_DESCTYPE_ADV_ONEBUF;
 	if (hw->mac.type >= e1000_82580)
 		srrctl |= E1000_SRRCTL_TIMESTAMP;
@@ -4771,8 +4788,16 @@ void igb_configure_rx_ring(struct igb_adapter *adapter,
 	u32 rxdctl = 0;
 
 	xdp_rxq_info_unreg_mem_model(&ring->xdp_rxq);
-	WARN_ON(xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
-					   MEM_TYPE_PAGE_SHARED, NULL));
+	ring->xsk_pool = igb_xsk_pool(adapter, ring);
+	if (ring->xsk_pool) {
+		WARN_ON(xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
+						   MEM_TYPE_XSK_BUFF_POOL,
+						   NULL));
+		xsk_pool_set_rxq_info(ring->xsk_pool, &ring->xdp_rxq);
+	} else {
+		WARN_ON(xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
+						   MEM_TYPE_PAGE_SHARED, NULL));
+	}
 
 	/* disable the queue */
 	wr32(E1000_RXDCTL(reg_idx), 0);
@@ -4892,7 +4917,9 @@ void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid)
 	 * at least 1 descriptor unused to make sure
 	 * next_to_use != next_to_clean
 	 */
-	igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));
+	rx_ring->xsk_pool ?
+		igb_alloc_rx_buffers_zc(rx_ring, igb_desc_unused(rx_ring)) :
+		igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));
 
 	clear_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
 }
@@ -5069,6 +5096,13 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
 	while (i != rx_ring->next_to_alloc) {
 		struct igb_rx_buffer *buffer_info = &rx_ring->rx_buffer_info[i];
 
+		if (rx_ring->xsk_pool) {
+			if (buffer_info->xdp)
+				xsk_buff_free(buffer_info->xdp);
+			buffer_info->xdp = NULL;
+			goto skip_for_xsk;
+		}
+
 		/* Invalidate cache lines that may have been written to by
 		 * device so that we avoid corrupting memory.
 		 */
@@ -5087,6 +5121,7 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
 		__page_frag_cache_drain(buffer_info->page,
 					buffer_info->pagecnt_bias);
 
+skip_for_xsk:
 		i++;
 		if (i == rx_ring->count)
 			i = 0;
@@ -6518,6 +6553,9 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 		return NETDEV_TX_BUSY;
 	}
 
+	if (unlikely(test_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags)))
+		return NETDEV_TX_BUSY;
+
 	/* record the location of the first descriptor for this packet */
 	first = &tx_ring->tx_buffer_info[tx_ring->next_to_use];
 	first->type = IGB_TYPE_SKB;
@@ -8260,7 +8298,9 @@ static int igb_poll(struct napi_struct *napi, int budget)
 		clean_complete = igb_clean_tx_irq(q_vector, budget);
 
 	if (q_vector->rx.ring) {
-		int cleaned = igb_clean_rx_irq(q_vector, budget);
+		int cleaned = q_vector->rx.ring->xsk_pool ?
+			igb_clean_rx_irq_zc(q_vector, budget) :
+			igb_clean_rx_irq(q_vector, budget);
 
 		work_done += cleaned;
 		if (cleaned >= budget)
@@ -8668,8 +8708,13 @@ struct sk_buff *igb_run_xdp(struct igb_adapter *adapter,
 		break;
 	case XDP_REDIRECT:
 		err = xdp_do_redirect(adapter->netdev, xdp, xdp_prog);
-		if (err)
+		if (err) {
+			if (xsk_uses_need_wakeup(rx_ring->xsk_pool) && err == -ENOBUFS)
+				result = IGB_XDP_EXIT;
+			else
+				result = IGB_XDP_CONSUMED;
 			goto out_failure;
+		}
 		result = IGB_XDP_REDIR;
 		break;
 	default:
@@ -8929,6 +8974,8 @@ static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
 	struct igb_adapter *adapter = q_vector->adapter;
 	struct igb_ring *rx_ring = q_vector->rx.ring;
 	struct sk_buff *skb = rx_ring->skb;
+	int cpu = smp_processor_id();
+	struct netdev_queue *nq;
 	unsigned int total_bytes = 0, total_packets = 0;
 	u16 cleaned_count = igb_desc_unused(rx_ring);
 	unsigned int xdp_xmit = 0;
@@ -9059,7 +9106,10 @@ static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
 	if (xdp_xmit & IGB_XDP_TX) {
 		struct igb_ring *tx_ring = igb_xdp_tx_queue_mapping(adapter);
 
+		nq = txring_txq(tx_ring);
+		__netif_tx_lock(nq, cpu);
 		igb_xdp_ring_update_tail(tx_ring);
+		__netif_tx_unlock(nq);
 	}
 
 	u64_stats_update_begin(&rx_ring->rx_syncp);
diff --git a/drivers/net/ethernet/intel/igb/igb_xsk.c b/drivers/net/ethernet/intel/igb/igb_xsk.c
new file mode 100644
index 000000000000..eae616e7608c
--- /dev/null
+++ b/drivers/net/ethernet/intel/igb/igb_xsk.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2018 Intel Corporation. */
+
+#include <linux/bpf_trace.h>
+#include <net/xdp_sock_drv.h>
+#include <net/xdp.h>
+
+#include "e1000_hw.h"
+#include "igb.h"
+
+struct xsk_buff_pool *igb_xsk_pool(struct igb_adapter *adapter,
+				   struct igb_ring *ring)
+{
+	int qid = ring->queue_index;
+
+	if (!igb_xdp_is_enabled(adapter) ||
+	    !test_bit(IGB_RING_FLAG_AF_XDP_ZC, &ring->flags))
+		return NULL;
+
+	return xsk_get_pool_from_qid(adapter->netdev, qid);
+}
+
+static int igb_xsk_pool_enable(struct igb_adapter *adapter,
+			       struct xsk_buff_pool *pool,
+			       u16 qid)
+{
+	struct net_device *netdev = adapter->netdev;
+	struct igb_ring *rx_ring;
+	bool if_running;
+	int err;
+
+	if (qid >= adapter->num_rx_queues)
+		return -EINVAL;
+
+	if (qid >= netdev->real_num_rx_queues)
+		return -EINVAL;
+
+	err = xsk_pool_dma_map(pool, &adapter->pdev->dev, IGB_RX_DMA_ATTR);
+	if (err)
+		return err;
+
+	rx_ring = adapter->rx_ring[qid];
+	if_running = netif_running(adapter->netdev) && igb_xdp_is_enabled(adapter);
+	if (if_running)
+		igb_txrx_ring_disable(adapter, qid);
+
+	set_bit(IGB_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
+
+	if (if_running) {
+		igb_txrx_ring_enable(adapter, qid);
+
+		/* Kick start the NAPI context so that receiving will start */
+		err = igb_xsk_wakeup(adapter->netdev, qid, XDP_WAKEUP_RX);
+		if (err) {
+			clear_bit(IGB_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
+			xsk_pool_dma_unmap(pool, IGB_RX_DMA_ATTR);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int igb_xsk_pool_disable(struct igb_adapter *adapter, u16 qid)
+{
+	struct igb_ring *rx_ring;
+	struct xsk_buff_pool *pool;
+	bool if_running;
+
+	pool = xsk_get_pool_from_qid(adapter->netdev, qid);
+	if (!pool)
+		return -EINVAL;
+
+	rx_ring = adapter->rx_ring[qid];
+	if_running = netif_running(adapter->netdev) && igb_xdp_is_enabled(adapter);
+	if (if_running)
+		igb_txrx_ring_disable(adapter, qid);
+
+	xsk_pool_dma_unmap(pool, IGB_RX_DMA_ATTR);
+	clear_bit(IGB_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
+
+	if (if_running)
+		igb_txrx_ring_enable(adapter, qid);
+
+	return 0;
+}
+
+int igb_xsk_pool_setup(struct igb_adapter *adapter,
+		       struct xsk_buff_pool *pool,
+		       u16 qid)
+{
+	return pool ? igb_xsk_pool_enable(adapter, pool, qid) :
+		igb_xsk_pool_disable(adapter, qid);
+}
+
+bool igb_alloc_rx_buffers_zc(struct igb_ring *rx_ring, u16 count)
+{
+	union e1000_adv_rx_desc *rx_desc;
+	struct igb_rx_buffer *buffer_info;
+	u16 i = rx_ring->next_to_use;
+	dma_addr_t dma;
+	bool ok = true;
+
+	/* nothing to do */
+	if (!count)
+		return true;
+
+	rx_desc = IGB_RX_DESC(rx_ring, i);
+	buffer_info = &rx_ring->rx_buffer_info[i];
+	i -= rx_ring->count;
+
+	do {
+		buffer_info->xdp = xsk_buff_alloc(rx_ring->xsk_pool);
+		if (!buffer_info->xdp) {
+			ok = false;
+			break;
+		}
+
+		dma = xsk_buff_xdp_get_dma(buffer_info->xdp);
+
+		/* Refresh the desc even if buffer_addrs didn't change
+		 * because each write-back erases this info.
+		 */
+		rx_desc->read.pkt_addr = cpu_to_le64(dma);
+
+		rx_desc++;
+		buffer_info++;
+		i++;
+		if (unlikely(!i)) {
+			rx_desc = IGB_RX_DESC(rx_ring, 0);
+			buffer_info = rx_ring->rx_buffer_info;
+			i -= rx_ring->count;
+		}
+
+		/* clear the length for the next_to_use descriptor */
+		rx_desc->wb.upper.length = 0;
+
+		count--;
+	} while (count);
+
+	i += rx_ring->count;
+
+	if (rx_ring->next_to_use != i) {
+		rx_ring->next_to_use = i;
+
+		/* Force memory writes to complete before letting h/w
+		 * know there are new descriptors to fetch.  (Only
+		 * applicable for weak-ordered memory model archs,
+		 * such as IA-64).
+		 */
+		wmb();
+		writel(i, rx_ring->tail);
+	}
+
+	return ok;
+}
+
+static struct sk_buff *igb_construct_skb_zc(struct igb_ring *rx_ring,
+					    struct xdp_buff *xdp,
+					    ktime_t timestamp)
+{
+	unsigned int totalsize = xdp->data_end - xdp->data_meta;
+	unsigned int metasize = xdp->data - xdp->data_meta;
+	struct sk_buff *skb;
+
+	net_prefetch(xdp->data_meta);
+
+	/* allocate a skb to store the frags */
+	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, totalsize,
+			       GFP_ATOMIC | __GFP_NOWARN);
+	if (unlikely(!skb))
+		return NULL;
+
+	if (timestamp)
+		skb_hwtstamps(skb)->hwtstamp = timestamp;
+
+	memcpy(__skb_put(skb, totalsize), xdp->data_meta,
+	       ALIGN(totalsize, sizeof(long)));
+
+	if (metasize) {
+		skb_metadata_set(skb, metasize);
+		__skb_pull(skb, metasize);
+	}
+
+	return skb;
+}
+
+static void igb_update_ntc(struct igb_ring *rx_ring)
+{
+	u32 ntc = rx_ring->next_to_clean + 1;
+
+	/* fetch, update, and store next to clean */
+	ntc = (ntc < rx_ring->count) ? ntc : 0;
+	rx_ring->next_to_clean = ntc;
+
+	prefetch(IGB_RX_DESC(rx_ring, ntc));
+}
+
+int igb_clean_rx_irq_zc(struct igb_q_vector *q_vector, const int budget)
+{
+	struct igb_adapter *adapter = q_vector->adapter;
+	struct igb_ring *rx_ring = q_vector->rx.ring;
+	struct sk_buff *skb;
+	int cpu = smp_processor_id();
+	struct netdev_queue *nq;
+	unsigned int total_bytes = 0, total_packets = 0;
+	u16 cleaned_count = igb_desc_unused(rx_ring);
+	unsigned int xdp_xmit = 0;
+	bool failure = false;
+
+	while (likely(total_packets < budget)) {
+		union e1000_adv_rx_desc *rx_desc;
+		struct igb_rx_buffer *rx_buffer;
+		ktime_t timestamp = 0;
+		unsigned int size;
+
+		/* return some buffers to hardware, one at a time is too slow */
+		if (cleaned_count >= IGB_RX_BUFFER_WRITE) {
+			igb_alloc_rx_buffers_zc(rx_ring, cleaned_count);
+			cleaned_count = 0;
+		}
+
+		rx_desc = IGB_RX_DESC(rx_ring, rx_ring->next_to_clean);
+		size = le16_to_cpu(rx_desc->wb.upper.length);
+		if (!size)
+			break;
+
+		/* This memory barrier is needed to keep us from reading
+		 * any other fields out of the rx_desc until we know the
+		 * descriptor has been written back
+		 */
+		dma_rmb();
+
+		rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
+		rx_buffer->xdp->data_end = rx_buffer->xdp->data + size;
+		xsk_buff_dma_sync_for_cpu(rx_buffer->xdp, rx_ring->xsk_pool);
+
+		/* pull rx packet timestamp if available and valid */
+		if (igb_test_staterr(rx_desc, E1000_RXDADV_STAT_TSIP)) {
+			int ts_hdr_len;
+
+			ts_hdr_len = igb_ptp_rx_pktstamp(rx_ring->q_vector,
+							 rx_buffer->xdp->data,
+							 &timestamp);
+
+			rx_buffer->xdp->data += ts_hdr_len;
+			rx_buffer->xdp->data_meta += ts_hdr_len;
+			size -= ts_hdr_len;
+		}
+
+		skb = igb_run_xdp(adapter, rx_ring, rx_buffer->xdp);
+
+		if (IS_ERR(skb)) {
+			unsigned int xdp_res = -PTR_ERR(skb);
+
+			if (likely(xdp_res & (IGB_XDP_TX | IGB_XDP_REDIR))) {
+				xdp_xmit |= xdp_res;
+			} else if (xdp_res == IGB_XDP_EXIT) {
+				failure = true;
+				break;
+			} else if (xdp_res == IGB_XDP_CONSUMED) {
+				xsk_buff_free(rx_buffer->xdp);
+			}
+
+			total_packets++;
+			total_bytes += size;
+
+			rx_buffer->xdp = NULL;
+			cleaned_count++;
+			igb_update_ntc(rx_ring);
+			continue;
+		}
+
+		skb = igb_construct_skb_zc(rx_ring, rx_buffer->xdp, timestamp);
+
+		/* exit if we failed to retrieve a buffer */
+		if (!skb) {
+			rx_ring->rx_stats.alloc_failed++;
+			break;
+		}
+
+		xsk_buff_free(rx_buffer->xdp);
+		rx_buffer->xdp = NULL;
+		cleaned_count++;
+		igb_update_ntc(rx_ring);
+
+		if (eth_skb_pad(skb))
+			continue;
+
+		/* probably a little skewed due to removing CRC */
+		total_bytes += skb->len;
+
+		/* populate checksum, timestamp, VLAN, and protocol */
+		igb_process_skb_fields(rx_ring, rx_desc, skb);
+
+		napi_gro_receive(&q_vector->napi, skb);
+
+		/* reset skb pointer */
+		skb = NULL;
+
+		/* update budget accounting */
+		total_packets++;
+	}
+
+	if (xdp_xmit & IGB_XDP_REDIR)
+		xdp_do_flush();
+
+	if (xdp_xmit & IGB_XDP_TX) {
+		struct igb_ring *tx_ring = igb_xdp_tx_queue_mapping(adapter);
+
+		nq = txring_txq(tx_ring);
+		__netif_tx_lock(nq, cpu);
+		igb_xdp_ring_update_tail(tx_ring);
+		__netif_tx_unlock(nq);
+	}
+
+	u64_stats_update_begin(&rx_ring->rx_syncp);
+	rx_ring->rx_stats.packets += total_packets;
+	rx_ring->rx_stats.bytes += total_bytes;
+	u64_stats_update_end(&rx_ring->rx_syncp);
+	q_vector->rx.total_packets += total_packets;
+	q_vector->rx.total_bytes += total_bytes;
+
+	if (cleaned_count)
+		igb_alloc_rx_buffers_zc(rx_ring, cleaned_count);
+
+	if (xsk_uses_need_wakeup(rx_ring->xsk_pool)) {
+		if (failure || rx_ring->next_to_clean == rx_ring->next_to_use)
+			xsk_set_rx_need_wakeup(rx_ring->xsk_pool);
+		else
+			xsk_clear_rx_need_wakeup(rx_ring->xsk_pool);
+
+		return (int)total_packets;
+	}
+	return failure ? budget : (int)total_packets;
+}
+
+int igb_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags)
+{
+	struct igb_adapter *adapter = netdev_priv(dev);
+	struct igb_ring *ring;
+	struct e1000_hw *hw = &adapter->hw;
+	u32 eics = 0;
+
+	if (test_bit(__IGB_DOWN, &adapter->state))
+		return -ENETDOWN;
+
+	if (!igb_xdp_is_enabled(adapter))
+		return -EINVAL;
+
+	if (qid >= adapter->num_tx_queues)
+		return -EINVAL;
+
+	ring = adapter->tx_ring[qid];
+
+	if (test_bit(IGB_RING_FLAG_TX_DISABLED, &ring->flags))
+		return -ENETDOWN;
+
+	if (!ring->xsk_pool)
+		return -EINVAL;
+
+	if (!napi_if_scheduled_mark_missed(&ring->q_vector->napi)) {
+		/* Cause software interrupt to ensure Rx ring is cleaned */
+		if (adapter->flags & IGB_FLAG_HAS_MSIX) {
+			eics |= ring->q_vector->eims_value;
+			wr32(E1000_EICS, eics);
+		} else {
+			wr32(E1000_ICS, E1000_ICS_RXDMT0);
+		}
+	}
+
+	return 0;
+}
-- 
2.34.1

Re: [PATCH 3/4] igb: add AF_XDP zero-copy Rx support

[Simon Horman]

On Tue, Jul 04, 2023 at 11:59:14AM +0200, Sriram Yagnaraman wrote:
> Add support for AF_XDP zero-copy receive path.
> 
> Add IGB_RING_FLAG_AF_XDP_ZC ring flag to indicate that a ring has AF_XDP
> zero-copy support. This flag is used in igb_configure_rx_ring to
> register XSK_BUFF_POOL (if zero-copy is enabled) memory model or the
> default PAGE_SHARED model otherwise.
> 
> When AF_XDP zero-copy is enabled, the rx buffers are allocated from the
> xsk buff pool using igb_alloc_rx_buffers_zc.
> 
> Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>

...

> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index 391c0eb136d9..f4dbb75d6eac 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -2013,7 +2013,9 @@ static void igb_configure(struct igb_adapter *adapter)
>  	 */
>  	for (i = 0; i < adapter->num_rx_queues; i++) {
>  		struct igb_ring *ring = adapter->rx_ring[i];
> -		igb_alloc_rx_buffers(ring, igb_desc_unused(ring));
> +		ring->xsk_pool ?
> +			igb_alloc_rx_buffers_zc(ring, igb_desc_unused(ring)) :
> +			igb_alloc_rx_buffers(ring, igb_desc_unused(ring));

This construction seems a little unusual (to me) as the result of
the ternary operator is not assigned. I wonder if it it would
be sensible to follow a simple if/else pattern here.o

Flagged by Sparse as:

 .../igb_main.c:2016:32: error: incompatible types in conditional expression (different base types):
 .../igb_main.c:2016:32:    bool
 .../igb_main.c:2016:32:    void

...

> @@ -4892,7 +4917,9 @@ void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid)
>  	 * at least 1 descriptor unused to make sure
>  	 * next_to_use != next_to_clean
>  	 */
> -	igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));
> +	rx_ring->xsk_pool ?
> +		igb_alloc_rx_buffers_zc(rx_ring, igb_desc_unused(rx_ring)) :
> +		igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));

Ditto.

...

> +static int igb_xsk_pool_disable(struct igb_adapter *adapter, u16 qid)
> +{
> +	struct igb_ring *rx_ring;
> +	struct xsk_buff_pool *pool;
> +	bool if_running;

Please use reverse xmas tree - longest line to shortest - for
new Networking code. Likewise elsewhere in this patch.
You can use the tool at the link below to help.

https://github.com/ecree-solarflare/xmastree

...

Re: [PATCH 3/4] igb: add AF_XDP zero-copy Rx support

[kernel test robot]

Hi Sriram,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tnguy-next-queue/dev-queue]
[also build test WARNING on tnguy-net-queue/dev-queue horms-ipvs/master linus/master v6.4 next-20230705]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sriram-Yagnaraman/igb-prepare-for-AF_XDP-zero-copy-support/20230704-180613
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue.git dev-queue
patch link:    https://lore.kernel.org/r/20230704095915.9750-4-sriram.yagnaraman%40est.tech
patch subject: [PATCH 3/4] igb: add AF_XDP zero-copy Rx support
config: openrisc-randconfig-r093-20230705 (https://download.01.org/0day-ci/archive/20230706/202307060154.LjqekYIL-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230706/202307060154.LjqekYIL-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307060154.LjqekYIL-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/net/ethernet/intel/igb/igb_main.c:2016:32: sparse: sparse: incompatible types in conditional expression (different base types):
>> drivers/net/ethernet/intel/igb/igb_main.c:2016:32: sparse:    bool
>> drivers/net/ethernet/intel/igb/igb_main.c:2016:32: sparse:    void
   drivers/net/ethernet/intel/igb/igb_main.c:4920:27: sparse: sparse: incompatible types in conditional expression (different base types):
   drivers/net/ethernet/intel/igb/igb_main.c:4920:27: sparse:    bool
   drivers/net/ethernet/intel/igb/igb_main.c:4920:27: sparse:    void

vim +2016 drivers/net/ethernet/intel/igb/igb_main.c

  1984	
  1985	/**
  1986	 *  igb_configure - configure the hardware for RX and TX
  1987	 *  @adapter: private board structure
  1988	 **/
  1989	static void igb_configure(struct igb_adapter *adapter)
  1990	{
  1991		struct net_device *netdev = adapter->netdev;
  1992		int i;
  1993	
  1994		igb_get_hw_control(adapter);
  1995		igb_set_rx_mode(netdev);
  1996		igb_setup_tx_mode(adapter);
  1997	
  1998		igb_restore_vlan(adapter);
  1999	
  2000		igb_setup_tctl(adapter);
  2001		igb_setup_mrqc(adapter);
  2002		igb_setup_rctl(adapter);
  2003	
  2004		igb_nfc_filter_restore(adapter);
  2005		igb_configure_tx(adapter);
  2006		igb_configure_rx(adapter);
  2007	
  2008		igb_rx_fifo_flush_82575(&adapter->hw);
  2009	
  2010		/* call igb_desc_unused which always leaves
  2011		 * at least 1 descriptor unused to make sure
  2012		 * next_to_use != next_to_clean
  2013		 */
  2014		for (i = 0; i < adapter->num_rx_queues; i++) {
  2015			struct igb_ring *ring = adapter->rx_ring[i];
> 2016			ring->xsk_pool ?
  2017				igb_alloc_rx_buffers_zc(ring, igb_desc_unused(ring)) :
  2018				igb_alloc_rx_buffers(ring, igb_desc_unused(ring));
  2019		}
  2020	}
  2021	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 4/4] igb: add AF_XDP zero-copy Tx support

[Sriram Yagnaraman]

Add support for AF_XDP zero-copy transmit path.

A new TX buffer type IGB_TYPE_XSK is introduced to indicate that the Tx
frame was allocated from the xsk buff pool, so igb_clean_tx_ring and
igb_clean_tx_irq can clean the buffers correctly based on type.

igb_xmit_zc performs the actual packet transmit when AF_XDP zero-copy is
enabled. We share the TX ring between slow path, XDP and AF_XDP
zero-copy, so we use the netdev queue lock to ensure mutual exclusion.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
---
 drivers/net/ethernet/intel/igb/igb.h      |  2 +
 drivers/net/ethernet/intel/igb/igb_main.c | 44 +++++++++++++--
 drivers/net/ethernet/intel/igb/igb_xsk.c  | 67 ++++++++++++++++++++++-
 3 files changed, 105 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 4f474d7338b5..564706ab0646 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -257,6 +257,7 @@ enum igb_tx_flags {
 enum igb_tx_buf_type {
 	IGB_TYPE_SKB = 0,
 	IGB_TYPE_XDP,
+	IGB_TYPE_XSK
 };
 
 /* wrapper around a pointer to a socket buffer,
@@ -843,6 +844,7 @@ int igb_xsk_pool_setup(struct igb_adapter *adapter,
 		       u16 qid);
 bool igb_alloc_rx_buffers_zc(struct igb_ring *rx_ring, u16 count);
 int igb_clean_rx_irq_zc(struct igb_q_vector *q_vector, const int budget);
+bool igb_xmit_zc(struct igb_ring *tx_ring, unsigned int budget);
 int igb_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags);
 
 #endif /* _IGB_H_ */
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index f4dbb75d6eac..c6bb5b1944c8 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4390,6 +4390,8 @@ void igb_configure_tx_ring(struct igb_adapter *adapter,
 	u64 tdba = ring->dma;
 	int reg_idx = ring->reg_idx;
 
+	ring->xsk_pool = igb_xsk_pool(adapter, ring);
+
 	wr32(E1000_TDLEN(reg_idx),
 	     ring->count * sizeof(union e1000_adv_tx_desc));
 	wr32(E1000_TDBAL(reg_idx),
@@ -4970,15 +4972,20 @@ static void igb_clean_tx_ring(struct igb_ring *tx_ring)
 {
 	u16 i = tx_ring->next_to_clean;
 	struct igb_tx_buffer *tx_buffer = &tx_ring->tx_buffer_info[i];
+	u32 xsk_frames = 0;
 
 	while (i != tx_ring->next_to_use) {
 		union e1000_adv_tx_desc *eop_desc, *tx_desc;
 
 		/* Free all the Tx ring sk_buffs or xdp frames */
-		if (tx_buffer->type == IGB_TYPE_SKB)
+		if (tx_buffer->type == IGB_TYPE_SKB) {
 			dev_kfree_skb_any(tx_buffer->skb);
-		else
+		} else if (tx_buffer->type == IGB_TYPE_XDP) {
 			xdp_return_frame(tx_buffer->xdpf);
+		} else if (tx_buffer->type == IGB_TYPE_XSK) {
+			xsk_frames++;
+			goto skip_for_xsk;
+		}
 
 		/* unmap skb header data */
 		dma_unmap_single(tx_ring->dev,
@@ -5009,6 +5016,7 @@ static void igb_clean_tx_ring(struct igb_ring *tx_ring)
 					       DMA_TO_DEVICE);
 		}
 
+skip_for_xsk:
 		tx_buffer->next_to_watch = NULL;
 
 		/* move us one more past the eop_desc for start of next pkt */
@@ -5023,6 +5031,9 @@ static void igb_clean_tx_ring(struct igb_ring *tx_ring)
 	/* reset BQL for queue */
 	netdev_tx_reset_queue(txring_txq(tx_ring));
 
+	if (tx_ring->xsk_pool && xsk_frames)
+		xsk_tx_completed(tx_ring->xsk_pool, xsk_frames);
+
 	/* reset next_to_use and next_to_clean */
 	tx_ring->next_to_use = 0;
 	tx_ring->next_to_clean = 0;
@@ -8330,12 +8341,16 @@ static int igb_poll(struct napi_struct *napi, int budget)
 static bool igb_clean_tx_irq(struct igb_q_vector *q_vector, int napi_budget)
 {
 	struct igb_adapter *adapter = q_vector->adapter;
+	int cpu = smp_processor_id();
 	struct igb_ring *tx_ring = q_vector->tx.ring;
 	struct igb_tx_buffer *tx_buffer;
 	union e1000_adv_tx_desc *tx_desc;
+	struct netdev_queue *nq;
 	unsigned int total_bytes = 0, total_packets = 0;
 	unsigned int budget = q_vector->tx.work_limit;
 	unsigned int i = tx_ring->next_to_clean;
+	u32 xsk_frames = 0;
+	bool xsk_xmit_done = true;
 
 	if (test_bit(__IGB_DOWN, &adapter->state))
 		return true;
@@ -8366,10 +8381,14 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector, int napi_budget)
 		total_packets += tx_buffer->gso_segs;
 
 		/* free the skb */
-		if (tx_buffer->type == IGB_TYPE_SKB)
+		if (tx_buffer->type == IGB_TYPE_SKB) {
 			napi_consume_skb(tx_buffer->skb, napi_budget);
-		else
+		} else if (tx_buffer->type == IGB_TYPE_XDP) {
 			xdp_return_frame(tx_buffer->xdpf);
+		} else if (tx_buffer->type == IGB_TYPE_XSK) {
+			xsk_frames++;
+			goto skip_for_xsk;
+		}
 
 		/* unmap skb header data */
 		dma_unmap_single(tx_ring->dev,
@@ -8401,6 +8420,7 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector, int napi_budget)
 			}
 		}
 
+skip_for_xsk:
 		/* move us one more past the eop_desc for start of next pkt */
 		tx_buffer++;
 		tx_desc++;
@@ -8429,6 +8449,20 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector, int napi_budget)
 	q_vector->tx.total_bytes += total_bytes;
 	q_vector->tx.total_packets += total_packets;
 
+	if (tx_ring->xsk_pool) {
+		if (xsk_frames)
+			xsk_tx_completed(tx_ring->xsk_pool, xsk_frames);
+		if (xsk_uses_need_wakeup(tx_ring->xsk_pool))
+			xsk_set_tx_need_wakeup(tx_ring->xsk_pool);
+
+		nq = txring_txq(tx_ring);
+		__netif_tx_lock(nq, cpu);
+		/* Avoid transmit queue timeout since we share it with the slow path */
+		txq_trans_cond_update(nq);
+		xsk_xmit_done = igb_xmit_zc(tx_ring, q_vector->tx.work_limit);
+		__netif_tx_unlock(nq);
+	}
+
 	if (test_bit(IGB_RING_FLAG_TX_DETECT_HANG, &tx_ring->flags)) {
 		struct e1000_hw *hw = &adapter->hw;
 
@@ -8491,7 +8525,7 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector, int napi_budget)
 		}
 	}
 
-	return !!budget;
+	return !!budget && xsk_xmit_done;
 }
 
 /**
diff --git a/drivers/net/ethernet/intel/igb/igb_xsk.c b/drivers/net/ethernet/intel/igb/igb_xsk.c
index eae616e7608c..8b60285ec242 100644
--- a/drivers/net/ethernet/intel/igb/igb_xsk.c
+++ b/drivers/net/ethernet/intel/igb/igb_xsk.c
@@ -25,25 +25,28 @@ static int igb_xsk_pool_enable(struct igb_adapter *adapter,
 			       u16 qid)
 {
 	struct net_device *netdev = adapter->netdev;
-	struct igb_ring *rx_ring;
+	struct igb_ring *tx_ring, *rx_ring;
 	bool if_running;
 	int err;
 
 	if (qid >= adapter->num_rx_queues)
 		return -EINVAL;
 
-	if (qid >= netdev->real_num_rx_queues)
+	if (qid >= netdev->real_num_rx_queues ||
+	    qid >= netdev->real_num_tx_queues)
 		return -EINVAL;
 
 	err = xsk_pool_dma_map(pool, &adapter->pdev->dev, IGB_RX_DMA_ATTR);
 	if (err)
 		return err;
 
+	tx_ring = adapter->tx_ring[qid];
 	rx_ring = adapter->rx_ring[qid];
 	if_running = netif_running(adapter->netdev) && igb_xdp_is_enabled(adapter);
 	if (if_running)
 		igb_txrx_ring_disable(adapter, qid);
 
+	set_bit(IGB_RING_FLAG_AF_XDP_ZC, &tx_ring->flags);
 	set_bit(IGB_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
 
 	if (if_running) {
@@ -52,6 +55,7 @@ static int igb_xsk_pool_enable(struct igb_adapter *adapter,
 		/* Kick start the NAPI context so that receiving will start */
 		err = igb_xsk_wakeup(adapter->netdev, qid, XDP_WAKEUP_RX);
 		if (err) {
+			clear_bit(IGB_RING_FLAG_AF_XDP_ZC, &tx_ring->flags);
 			clear_bit(IGB_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
 			xsk_pool_dma_unmap(pool, IGB_RX_DMA_ATTR);
 			return err;
@@ -63,7 +67,7 @@ static int igb_xsk_pool_enable(struct igb_adapter *adapter,
 
 static int igb_xsk_pool_disable(struct igb_adapter *adapter, u16 qid)
 {
-	struct igb_ring *rx_ring;
+	struct igb_ring *tx_ring, *rx_ring;
 	struct xsk_buff_pool *pool;
 	bool if_running;
 
@@ -71,12 +75,14 @@ static int igb_xsk_pool_disable(struct igb_adapter *adapter, u16 qid)
 	if (!pool)
 		return -EINVAL;
 
+	tx_ring = adapter->tx_ring[qid];
 	rx_ring = adapter->rx_ring[qid];
 	if_running = netif_running(adapter->netdev) && igb_xdp_is_enabled(adapter);
 	if (if_running)
 		igb_txrx_ring_disable(adapter, qid);
 
 	xsk_pool_dma_unmap(pool, IGB_RX_DMA_ATTR);
+	clear_bit(IGB_RING_FLAG_AF_XDP_ZC, &tx_ring->flags);
 	clear_bit(IGB_RING_FLAG_AF_XDP_ZC, &rx_ring->flags);
 
 	if (if_running)
@@ -335,6 +341,61 @@ int igb_clean_rx_irq_zc(struct igb_q_vector *q_vector, const int budget)
 	return failure ? budget : (int)total_packets;
 }
 
+bool igb_xmit_zc(struct igb_ring *tx_ring, unsigned int budget)
+{
+	struct xsk_buff_pool *pool = tx_ring->xsk_pool;
+	union e1000_adv_tx_desc *tx_desc = NULL;
+	struct igb_tx_buffer *tx_bi;
+	bool work_done = true;
+	struct xdp_desc desc;
+	dma_addr_t dma;
+	u32 cmd_type;
+
+	while (budget-- > 0) {
+		if (unlikely(!igb_desc_unused(tx_ring))) {
+			work_done = false;
+			break;
+		}
+
+		if (!netif_carrier_ok(tx_ring->netdev))
+			break;
+
+		if (!xsk_tx_peek_desc(pool, &desc))
+			break;
+
+		dma = xsk_buff_raw_get_dma(pool, desc.addr);
+		xsk_buff_raw_dma_sync_for_device(pool, dma, desc.len);
+
+		tx_bi = &tx_ring->tx_buffer_info[tx_ring->next_to_use];
+		tx_bi->bytecount = desc.len;
+		tx_bi->type = IGB_TYPE_XSK;
+		tx_bi->xdpf = NULL;
+		tx_bi->gso_segs = 1;
+
+		tx_desc = IGB_TX_DESC(tx_ring, tx_ring->next_to_use);
+		tx_desc->read.buffer_addr = cpu_to_le64(dma);
+
+		/* put descriptor type bits */
+		cmd_type = E1000_ADVTXD_DTYP_DATA | E1000_ADVTXD_DCMD_DEXT |
+			   E1000_ADVTXD_DCMD_IFCS;
+
+		cmd_type |= desc.len | IGB_TXD_DCMD;
+		tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
+		tx_desc->read.olinfo_status = 0;
+
+		tx_ring->next_to_use++;
+		if (tx_ring->next_to_use == tx_ring->count)
+			tx_ring->next_to_use = 0;
+	}
+
+	if (tx_desc) {
+		igb_xdp_ring_update_tail(tx_ring);
+		xsk_tx_release(pool);
+	}
+
+	return !!budget && work_done;
+}
+
 int igb_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags)
 {
 	struct igb_adapter *adapter = netdev_priv(dev);
-- 
2.34.1

Re: [PATCH 0/4] igb: Add support for AF_XDP zero-copy

[Maciej Fijalkowski]

On Tue, Jul 04, 2023 at 11:59:11AM +0200, Sriram Yagnaraman wrote:

Hi Sriram,

> Disclaimer: My first patches to Intel drivers, implemented AF_XDP
> zero-copy feature which seemed to be missing for igb. Not sure if it was
> a conscious choice to not spend time implementing this for older
> devices, nevertheless I send them to the list for review.
> 
> The first couple of patches adds helper funcctions to prepare for AF_XDP
> zero-copy support which comes in the last couple of patches, one each
> for Rx and TX paths.

please include perf numbers in cover letter, CC AF_XDP maintainers and use
batch XSK APIs: xsk_buff_alloc_batch(), xsk_tx_peek_release_desc_batch().

Thanks!

> 
> Sriram Yagnaraman (4):
>   igb: prepare for AF_XDP zero-copy support
>   igb: Introduce txrx ring enable/disable functions
>   igb: add AF_XDP zero-copy Rx support
>   igb: add AF_XDP zero-copy Tx support
> 
>  drivers/net/ethernet/intel/igb/Makefile   |   2 +-
>  drivers/net/ethernet/intel/igb/igb.h      |  52 ++-
>  drivers/net/ethernet/intel/igb/igb_main.c | 178 +++++++--
>  drivers/net/ethernet/intel/igb/igb_xsk.c  | 434 ++++++++++++++++++++++
>  4 files changed, 633 insertions(+), 33 deletions(-)
>  create mode 100644 drivers/net/ethernet/intel/igb/igb_xsk.c
> 
> -- 
> 2.34.1
> 
> 

RE: [PATCH 0/4] igb: Add support for AF_XDP zero-copy

[Sriram Yagnaraman]

> -----Original Message-----
> From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> Sent: Tuesday, 4 July 2023 17:37
> To: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
> Cc: intel-wired-lan@lists.osuosl.org; bpf@vger.kernel.org;
> netdev@vger.kernel.org; Jesse Brandeburg <jesse.brandeburg@intel.com>;
> Tony Nguyen <anthony.l.nguyen@intel.com>; David S . Miller
> <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
> Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Alexei
> Starovoitov <ast@kernel.org>; Daniel Borkmann <daniel@iogearbox.net>;
> Jesper Dangaard Brouer <hawk@kernel.org>; John Fastabend
> <john.fastabend@gmail.com>
> Subject: Re: [PATCH 0/4] igb: Add support for AF_XDP zero-copy
> 
> On Tue, Jul 04, 2023 at 11:59:11AM +0200, Sriram Yagnaraman wrote:
> 
> Hi Sriram,
> 
> > Disclaimer: My first patches to Intel drivers, implemented AF_XDP
> > zero-copy feature which seemed to be missing for igb. Not sure if it
> > was a conscious choice to not spend time implementing this for older
> > devices, nevertheless I send them to the list for review.
> >
> > The first couple of patches adds helper funcctions to prepare for
> > AF_XDP zero-copy support which comes in the last couple of patches,
> > one each for Rx and TX paths.
> 
> please include perf numbers in cover letter, CC AF_XDP maintainers and use
> batch XSK APIs: xsk_buff_alloc_batch(), xsk_tx_peek_release_desc_batch().
> 
> Thanks!
> 

Thank you so much for the quick reply. I will respin addressing your comments.

For the perf numbers, I must confess, I only used the newly delivered IGB device emulation in qemu. I don't have access to a real NIC to provide realistic numbers. But of course, I can provide a comparison between XSK_COPY and XSK_ZEROCOPY using the emulator.
	
> >
> > Sriram Yagnaraman (4):
> >   igb: prepare for AF_XDP zero-copy support
> >   igb: Introduce txrx ring enable/disable functions
> >   igb: add AF_XDP zero-copy Rx support
> >   igb: add AF_XDP zero-copy Tx support
> >
> >  drivers/net/ethernet/intel/igb/Makefile   |   2 +-
> >  drivers/net/ethernet/intel/igb/igb.h      |  52 ++-
> >  drivers/net/ethernet/intel/igb/igb_main.c | 178 +++++++--
> > drivers/net/ethernet/intel/igb/igb_xsk.c  | 434 ++++++++++++++++++++++
> >  4 files changed, 633 insertions(+), 33 deletions(-)  create mode
> > 100644 drivers/net/ethernet/intel/igb/igb_xsk.c
> >
> > --
> > 2.34.1
> >
> >

[PATCH 0/4] igb: Add support for AF_XDP zero-copy

[Sriram Yagnaraman]

Disclaimer: My first patches to Intel drivers, implemented AF_XDP
zero-copy feature which seemed to be missing for igb. Not sure if it was
a conscious choice to not spend time implementing this for older
devices, nevertheless I send them to the list for review.

The first couple of patches adds helper funcctions to prepare for AF_XDP
zero-copy support which comes in the last couple of patches, one each
for Rx and TX paths.

Sriram Yagnaraman (4):
  igb: prepare for AF_XDP zero-copy support
  igb: Introduce txrx ring enable/disable functions
  igb: add AF_XDP zero-copy Rx support
  igb: add AF_XDP zero-copy Tx support

 drivers/net/ethernet/intel/igb/Makefile   |   2 +-
 drivers/net/ethernet/intel/igb/igb.h      |  52 ++-
 drivers/net/ethernet/intel/igb/igb_main.c | 178 +++++++--
 drivers/net/ethernet/intel/igb/igb_xsk.c  | 434 ++++++++++++++++++++++
 4 files changed, 633 insertions(+), 33 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/igb/igb_xsk.c

-- 
2.34.1