bnxt_en: Add XDP Metadata support

- Change the last arg to xdp_prepare_buff to true from false.
- Ensure that when XDP_PASS is returned the xdp->data_meta area
is copied to the skb->data area. Account for the meta data
size on skb allocation and do a pull after to move it to the
"reserved" zone.
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240402093753.331120-6-pavan.chebbi@broadcom.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -1296,7 +1296,7 @@ static int bnxt_agg_bufs_valid(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	return RX_AGG_CMP_VALID(agg, *raw_cons);
 }
 
-static inline struct sk_buff *bnxt_copy_skb(struct bnxt_napi *bnapi, u8 *data,
+static struct sk_buff *bnxt_copy_data(struct bnxt_napi *bnapi, u8 *data,
 				      unsigned int len,
 				      dma_addr_t mapping)
 {
@@ -1318,6 +1318,39 @@ static inline struct sk_buff *bnxt_copy_skb(struct bnxt_napi *bnapi, u8 *data,
 				   bp->rx_dir);
 
 	skb_put(skb, len);
+
+	return skb;
+}
+
+static struct sk_buff *bnxt_copy_skb(struct bnxt_napi *bnapi, u8 *data,
+				     unsigned int len,
+				     dma_addr_t mapping)
+{
+	return bnxt_copy_data(bnapi, data, len, mapping);
+}
+
+static struct sk_buff *bnxt_copy_xdp(struct bnxt_napi *bnapi,
+				     struct xdp_buff *xdp,
+				     unsigned int len,
+				     dma_addr_t mapping)
+{
+	unsigned int metasize = 0;
+	u8 *data = xdp->data;
+	struct sk_buff *skb;
+
+	len = xdp->data_end - xdp->data_meta;
+	metasize = xdp->data - xdp->data_meta;
+	data = xdp->data_meta;
+
+	skb = bnxt_copy_data(bnapi, data, len, mapping);
+	if (!skb)
+		return skb;
+
+	if (metasize) {
+		skb_metadata_set(skb, metasize);
+		__skb_pull(skb, metasize);
+	}
+
 	return skb;
 }
 
@@ -2111,7 +2144,10 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	}
 
 	if (len <= bp->rx_copy_thresh) {
+		if (!xdp_active)
 			skb = bnxt_copy_skb(bnapi, data_ptr, len, dma_addr);
+		else
+			skb = bnxt_copy_xdp(bnapi, &xdp, len, dma_addr);
 		bnxt_reuse_rx_data(rxr, cons, data);
 		if (!skb) {
 			if (agg_bufs) {

drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c

@@ -197,7 +197,7 @@ void bnxt_xdp_buff_init(struct bnxt *bp, struct bnxt_rx_ring_info *rxr,
 	dma_sync_single_for_cpu(&pdev->dev, mapping + offset, len, bp->rx_dir);
 
 	xdp_init_buff(xdp, buflen, &rxr->xdp_rxq);
-	xdp_prepare_buff(xdp, data_ptr - offset, offset, len, false);
+	xdp_prepare_buff(xdp, data_ptr - offset, offset, len, true);
 }
 
 void bnxt_xdp_buff_frags_free(struct bnxt_rx_ring_info *rxr,