net/mlx5e: Refactor xmit functions

A huge function mlx5e_sq_xmit was split into several to achieve multiple
goals:

1. Reuse the code in IPoIB.

2. Better intergrate with TLS, IPSEC, GENEVE and checksum offloads. Now
it's possible to reserve space in the WQ before running eseg-based
offloads, so:

2.1. It's not needed to copy cseg and eseg after mlx5e_fill_sq_frag_edge
anymore.

2.2. mlx5e_txqsq_get_next_pi will be used instead of the legacy
mlx5e_fill_sq_frag_edge for better code maintainability and reuse.

3. Prepare for the upcoming TX MPWQE for SKBs. It will intervene after
mlx5e_sq_calc_wqe_attr to check if it's possible to use MPWQE, and the
code flow will split into two paths: MPWQE and non-MPWQE.

Two high-level functions are provided to send packets:

* mlx5e_xmit is called by the networking stack, runs offloads and sends
the packet. In one of the following patches, MPWQE support will be added
to this flow.

* mlx5e_sq_xmit_simple is called by the TLS offload, runs only the
checksum offload and sends the packet.

This change has no performance impact in TCP single stream test and
XDP_TX single stream test.

When compiled with a recent GCC, this change shows no visible
performance impact on UDP pktgen (burst 32) single stream test either:
  Packet rate: 16.86 Mpps (±0.15 Mpps) -> 16.95 Mpps (±0.15 Mpps)
  Instructions per packet: 434 -> 429
  Cycles per packet: 158 -> 160
  Instructions per cycle: 2.75 -> 2.69

CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (x86_64)
NIC: Mellanox ConnectX-6 Dx
GCC 10.2.0

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

1 files changed, 1 insertions, 5 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/tls_rxtx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/tls_rxtx.c
index b0c31d49ff8d..c36560b3e93d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/tls_rxtx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/tls_rxtx.c
@@ -189,12 +189,10 @@ static bool mlx5e_tls_handle_ooo(struct mlx5e_tls_offload_context_tx *context,
 				 struct mlx5e_tls *tls)
 {
 	u32 tcp_seq = ntohl(tcp_hdr(skb)->seq);
-	struct mlx5e_tx_wqe *wqe;
 	struct sync_info info;
 	struct sk_buff *nskb;
 	int linear_len = 0;
 	int headln;
-	u16 pi;
 	int i;
 
 	sq->stats->tls_ooo++;
@@ -246,9 +244,7 @@ static bool mlx5e_tls_handle_ooo(struct mlx5e_tls_offload_context_tx *context,
 	sq->stats->tls_resync_bytes += nskb->len;
 	mlx5e_tls_complete_sync_skb(skb, nskb, tcp_seq, headln,
 				    cpu_to_be64(info.rcd_sn));
-	pi = mlx5_wq_cyc_ctr2ix(&sq->wq, sq->pc);
-	wqe = MLX5E_TX_FETCH_WQE(sq, pi);
-	mlx5e_sq_xmit(sq, nskb, wqe, pi, true);
+	mlx5e_sq_xmit_simple(sq, nskb, true);
 
 	return true;