[PATCH bpf-next 11/15] ice: set skb RX metadata from the skb core extension area of xdp_buff

[Tianyi Gao <tianyi@cloudflare.com>]

On XDP_PASS, ice builds the skb with xdp_build_skb_from_buff(). Then
ice_process_skb_fields() sets the hash and ip_summed from the RX
descriptor, and ice_receive_skb() adds the VLAN tag. The values that the
XDP program stored in the skb core extension area are not used.

ice_clean_rx_irq() takes the skb core extension pointer from the
xdp_buff before it builds the skb, and passes it to ice_receive_skb().
ice_receive_skb() calls xdp_skb_ext_to_skb() right before GRO. The
stored values then replace the values from the descriptor before the skb
leaves the driver. ice now sets the skb-ext-pass XDP feature.

Zero-copy is not supported in this patch. ice_clean_rx_irq_zc() passes
NULL for the skb core extension pointer to ice_receive_skb(). Hence the
skb-ext-pass feature does not cover AF_XDP zero-copy queues.

Export xdp_skb_ext_to_skb(), because ice can be a module.

Signed-off-by: Tianyi Gao <tianyi@cloudflare.com>
---
 drivers/net/ethernet/intel/ice/ice_main.c     | 3 ++-
 drivers/net/ethernet/intel/ice/ice_sf_eth.c   | 3 ++-
 drivers/net/ethernet/intel/ice/ice_txrx.c     | 4 +++-
 drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 7 ++++++-
 drivers/net/ethernet/intel/ice/ice_txrx_lib.h | 3 ++-
 drivers/net/ethernet/intel/ice/ice_xsk.c      | 2 +-
 net/core/xdp.c                                | 5 ++++-
 7 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 454fba07d4ec..cb619689d11a 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -3461,7 +3461,8 @@ static void ice_set_ops(struct ice_vsi *vsi)
 
 	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
 			       NETDEV_XDP_ACT_XSK_ZEROCOPY |
-			       NETDEV_XDP_ACT_RX_SG;
+			       NETDEV_XDP_ACT_RX_SG |
+			       NETDEV_XDP_ACT_SKB_EXT_PASS;
 	netdev->xdp_zc_max_segs = ICE_MAX_BUF_TXD;
 }
 
diff --git a/drivers/net/ethernet/intel/ice/ice_sf_eth.c b/drivers/net/ethernet/intel/ice/ice_sf_eth.c
index a730aa368c92..90f2ce5da022 100644
--- a/drivers/net/ethernet/intel/ice/ice_sf_eth.c
+++ b/drivers/net/ethernet/intel/ice/ice_sf_eth.c
@@ -52,7 +52,8 @@ static int ice_sf_cfg_netdev(struct ice_dynamic_port *dyn_port,
 
 	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
 			       NETDEV_XDP_ACT_XSK_ZEROCOPY |
-			       NETDEV_XDP_ACT_RX_SG;
+			       NETDEV_XDP_ACT_RX_SG |
+			       NETDEV_XDP_ACT_SKB_EXT_PASS;
 	netdev->xdp_zc_max_segs = ICE_MAX_BUF_TXD;
 
 	eth_hw_addr_set(netdev, dyn_port->hw_addr);
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index a2c7c4962882..06a1a5fdc43b 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -966,6 +966,7 @@ static int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 	/* start the loop to process Rx packets bounded by 'budget' */
 	while (likely(total_rx_pkts < (unsigned int)budget)) {
 		union ice_32b_rx_flex_desc *rx_desc;
+		const struct xdp_skb_ext *ext;
 		struct libeth_fqe *rx_buf;
 		struct sk_buff *skb;
 		unsigned int size;
@@ -1041,6 +1042,7 @@ static int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		continue;
 
 construct_skb:
+		ext = xdp_buff_skb_ext(&xdp->base);
 		skb = xdp_build_skb_from_buff(&xdp->base);
 		xdp->data = NULL;
 
@@ -1061,7 +1063,7 @@ static int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 
 		ice_trace(clean_rx_irq_indicate, rx_ring, rx_desc, skb);
 		/* send completed skb up the stack */
-		ice_receive_skb(rx_ring, skb, vlan_tci);
+		ice_receive_skb(rx_ring, skb, vlan_tci, ext);
 
 		/* update budget accounting */
 		total_rx_pkts++;
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
index e695a664e53d..85439853596f 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
@@ -247,17 +247,22 @@ ice_process_skb_fields(struct ice_rx_ring *rx_ring,
  * @rx_ring: Rx ring in play
  * @skb: packet to send up
  * @vlan_tci: VLAN TCI for packet
+ * @ext: skb core extension area of the packet, or NULL
  *
  * This function sends the completed packet (via. skb) up the stack using
  * gro receive functions (with/without VLAN tag)
  */
 void
-ice_receive_skb(struct ice_rx_ring *rx_ring, struct sk_buff *skb, u16 vlan_tci)
+ice_receive_skb(struct ice_rx_ring *rx_ring, struct sk_buff *skb, u16 vlan_tci,
+		const struct xdp_skb_ext *ext)
 {
 	if ((vlan_tci & VLAN_VID_MASK) && rx_ring->vlan_proto)
 		__vlan_hwaccel_put_tag(skb, rx_ring->vlan_proto,
 				       vlan_tci);
 
+	if (ext)
+		xdp_skb_ext_to_skb(skb, ext);
+
 	napi_gro_receive(&rx_ring->q_vector->napi, skb);
 }
 
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.h b/drivers/net/ethernet/intel/ice/ice_txrx_lib.h
index f17990b68b62..cfc77847696e 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.h
+++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.h
@@ -133,6 +133,7 @@ ice_process_skb_fields(struct ice_rx_ring *rx_ring,
 		       union ice_32b_rx_flex_desc *rx_desc,
 		       struct sk_buff *skb);
 void
-ice_receive_skb(struct ice_rx_ring *rx_ring, struct sk_buff *skb, u16 vlan_tci);
+ice_receive_skb(struct ice_rx_ring *rx_ring, struct sk_buff *skb, u16 vlan_tci,
+		const struct xdp_skb_ext *ext);
 
 #endif /* !_ICE_TXRX_LIB_H_ */
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index 0643017541c3..f64659dc8313 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -670,7 +670,7 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring,
 		vlan_tci = ice_get_vlan_tci(rx_desc);
 
 		ice_process_skb_fields(rx_ring, rx_desc, skb);
-		ice_receive_skb(rx_ring, skb, vlan_tci);
+		ice_receive_skb(rx_ring, skb, vlan_tci, NULL);
 	}
 
 	rx_ring->next_to_clean = ntc;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 984299199906..fdda072a5858 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -1086,7 +1086,9 @@ static const void *xdp_skb_ext_get(const struct xdp_skb_ext *ext,
  * @skb: The skb that is built from the packet.
  * @ext: The skb core extension area of the packet.
  *
- * Call it only when the packet has the XDP_FLAGS_HAS_SKB_EXT flag.
+ * Call it only when the packet has the XDP_FLAGS_HAS_SKB_EXT flag. A driver
+ * calls it after it sets the skb fields from the RX descriptor, and sets
+ * NETDEV_XDP_ACT_SKB_EXT_PASS.
  */
 void xdp_skb_ext_to_skb(struct sk_buff *skb, const struct xdp_skb_ext *ext)
 {
@@ -1115,6 +1117,7 @@ void xdp_skb_ext_to_skb(struct sk_buff *skb, const struct xdp_skb_ext *ext)
 		skb->csum_level = csum->level;
 	}
 }
+EXPORT_SYMBOL_GPL(xdp_skb_ext_to_skb);
 
 /**
  * xdp_skb_ext_warn_pass - Warn if XDP_PASS does not use the stored values.
-- 
2.56.0