On Mon, 30 Jan 2017 20:49:35 -0500, Michael Chan wrote:
> +static int bnxt_xmit_xdp(struct bnxt *bp, struct bnxt_napi *bnapi,
> + struct page *page, dma_addr_t mapping, u32 offset,
> + u32 len)
> +{
> + struct bnxt_tx_ring_info *txr = bnapi->tx_ring;
> + struct bnxt_sw_tx_bd *tx_buf;
> + struct tx_bd_ext *txbd1;
> + struct tx_bd *txbd;
> + u32 flags;
> + u16 prod;
> +
> + if (bnxt_tx_avail(bp, txr) < 2)
> + return -ENOSPC;
> +
> + prod = txr->tx_prod;
> + txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
> +
> + tx_buf = &txr->tx_buf_ring[prod];
> + tx_buf->page = page;
> + dma_unmap_addr_set(tx_buf, mapping, mapping);
> + flags = (len << TX_BD_LEN_SHIFT) | TX_BD_TYPE_LONG_TX_BD |
> + (2 << 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 + offset);
> +
> + 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;
> + return 0;
> +}
Are you not lacking DMA syncs in general? You map the buffers
bidirectionally, but I failed to find any dma_syncs. I would expect
one before you run xdp and one before you TX because packet could have
been modified. What am I missing?
