bnxt_en: Use short TX BDs for the XDP TX ring.

No offload is performed on the XDP_TX ring so we can use the short TX
BDs.  This has the effect of doubling the size of the XDP TX ring so
that it now matches the size of the rx ring by default.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -23,7 +23,6 @@ void bnxt_xmit_xdp(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
 		   dma_addr_t mapping, u32 len, u16 rx_prod)
 {
 	struct bnxt_sw_tx_bd *tx_buf;
-	struct tx_bd_ext *txbd1;
 	struct tx_bd *txbd;
 	u32 flags;
 	u16 prod;
@@ -33,22 +32,12 @@ void bnxt_xmit_xdp(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
 	tx_buf->rx_prod = rx_prod;
 
 	txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
-	flags = (len << TX_BD_LEN_SHIFT) | TX_BD_TYPE_LONG_TX_BD |
-		(2 << TX_BD_FLAGS_BD_CNT_SHIFT) | TX_BD_FLAGS_COAL_NOW |
+	flags = (len << TX_BD_LEN_SHIFT) | (1 << TX_BD_FLAGS_BD_CNT_SHIFT) |
 		TX_BD_FLAGS_PACKET_END | bnxt_lhint_arr[len >> 9];
 	txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
 	txbd->tx_bd_opaque = prod;
 	txbd->tx_bd_haddr = cpu_to_le64(mapping);
 
-	prod = NEXT_TX(prod);
-	txbd1 = (struct tx_bd_ext *)
-		&txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
-
-	txbd1->tx_bd_hsize_lflags = cpu_to_le32(0);
-	txbd1->tx_bd_mss = cpu_to_le32(0);
-	txbd1->tx_bd_cfa_action = cpu_to_le32(0);
-	txbd1->tx_bd_cfa_meta = cpu_to_le32(0);
-
 	prod = NEXT_TX(prod);
 	txr->tx_prod = prod;
 }
@@ -66,7 +55,6 @@ void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)
 	for (i = 0; i < nr_pkts; i++) {
 		last_tx_cons = tx_cons;
 		tx_cons = NEXT_TX(tx_cons);
-		tx_cons = NEXT_TX(tx_cons);
 	}
 	txr->tx_cons = tx_cons;
 	if (bnxt_tx_avail(bp, txr) == bp->tx_ring_size) {
@@ -133,7 +121,7 @@ bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
 		return false;
 
 	case XDP_TX:
-		if (tx_avail < 2) {
+		if (tx_avail < 1) {
 			trace_xdp_exception(bp->dev, xdp_prog, act);
 			bnxt_reuse_rx_data(rxr, cons, page);
 			return true;