net: mlx5: Add xdp tx return bulking support

Convert mlx5 driver to xdp_return_frame_bulk APIs.

XDP_REDIRECT (upstream codepath): 8.9Mpps
XDP_REDIRECT (upstream codepath + bulking APIs): 10.2Mpps
Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/250460319fd868b7b5668fc1deca74dd42813a90.1605267335.git.lorenzo@kernel.org

drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c

@@ -366,7 +366,8 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
 static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq,
 				  struct mlx5e_xdp_wqe_info *wi,
 				  u32 *xsk_frames,
-				  bool recycle)
+				  bool recycle,
+				  struct xdp_frame_bulk *bq)
 {
 	struct mlx5e_xdp_info_fifo *xdpi_fifo = &sq->db.xdpi_fifo;
 	u16 i;
@@ -379,7 +380,7 @@ static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq,
 			/* XDP_TX from the XSK RQ and XDP_REDIRECT */
 			dma_unmap_single(sq->pdev, xdpi.frame.dma_addr,
 					 xdpi.frame.xdpf->len, DMA_TO_DEVICE);
-			xdp_return_frame(xdpi.frame.xdpf);
+			xdp_return_frame_bulk(xdpi.frame.xdpf, bq);
 			break;
 		case MLX5E_XDP_XMIT_MODE_PAGE:
 			/* XDP_TX from the regular RQ */
@@ -397,12 +398,15 @@ static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq,
 
 bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)
 {
+	struct xdp_frame_bulk bq;
 	struct mlx5e_xdpsq *sq;
 	struct mlx5_cqe64 *cqe;
 	u32 xsk_frames = 0;
 	u16 sqcc;
 	int i;
 
+	xdp_frame_bulk_init(&bq);
+
 	sq = container_of(cq, struct mlx5e_xdpsq, cq);
 
 	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))
@@ -434,7 +438,7 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)
 
 			sqcc += wi->num_wqebbs;
 
-			mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, true);
+			mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, true, &bq);
 		} while (!last_wqe);
 
 		if (unlikely(get_cqe_opcode(cqe) != MLX5_CQE_REQ)) {
@@ -447,6 +451,8 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)
 		}
 	} while ((++i < MLX5E_TX_CQ_POLL_BUDGET) && (cqe = mlx5_cqwq_get_cqe(&cq->wq)));
 
+	xdp_flush_frame_bulk(&bq);
+
 	if (xsk_frames)
 		xsk_tx_completed(sq->xsk_pool, xsk_frames);
 
@@ -463,8 +469,13 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)
 
 void mlx5e_free_xdpsq_descs(struct mlx5e_xdpsq *sq)
 {
+	struct xdp_frame_bulk bq;
 	u32 xsk_frames = 0;
 
+	xdp_frame_bulk_init(&bq);
+
+	rcu_read_lock(); /* need for xdp_return_frame_bulk */
+
 	while (sq->cc != sq->pc) {
 		struct mlx5e_xdp_wqe_info *wi;
 		u16 ci;
@@ -474,9 +485,12 @@ void mlx5e_free_xdpsq_descs(struct mlx5e_xdpsq *sq)
 
 		sq->cc += wi->num_wqebbs;
 
-		mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, false);
+		mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, false, &bq);
 	}
 
+	xdp_flush_frame_bulk(&bq);
+	rcu_read_unlock();
+
 	if (xsk_frames)
 		xsk_tx_completed(sq->xsk_pool, xsk_frames);
 }