Re: [RFC-v3 9/9] iser-target: Add iSCSI Extensions for RDMA (iSER) target driver

Or Gerlitz
2013-04-04T09:51:20Z

On 04/04/2013 10:24, Nicholas A. Bellinger wrote:
> +static int
> +isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
> +{
> + struct isert_cmd *isert_cmd = container_of(cmd,
> + struct isert_cmd, iscsi_cmd);
> + struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
> + struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;
> + struct iscsi_scsi_rsp *hdr = (struct iscsi_scsi_rsp *)
> + &isert_cmd->tx_desc.iscsi_header;
> +
> + isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
> + iscsit_build_rsp_pdu(cmd, conn, true, hdr);
> + isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
> + /*
> + * Attach SENSE DATA payload to iSCSI Response PDU
> + */
> + if (cmd->se_cmd.sense_buffer &&
> + ((cmd->se_cmd.se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
> + (cmd->se_cmd.se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
> + struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
> + struct ib_sge *tx_dsg = &isert_cmd->tx_desc.tx_sg[1];
> + u32 padding, sense_len;
> +
> + put_unaligned_be16(cmd->se_cmd.scsi_sense_length,
> + cmd->sense_buffer);
> + cmd->se_cmd.scsi_sense_length += sizeof(__be16);
> +
> + padding = -(cmd->se_cmd.scsi_sense_length) & 3;
> + hton24(hdr->dlength, (u32)cmd->se_cmd.scsi_sense_length);
> + sense_len = cmd->se_cmd.scsi_sense_length + padding;
> +
> + isert_cmd->sense_buf_dma = ib_dma_map_single(ib_dev,
> + (void *)cmd->sense_buffer, sense_len,
> + DMA_TO_DEVICE);
> +
> + isert_cmd->sense_buf_len = sense_len;
> + ib_dma_sync_single_for_cpu(ib_dev, isert_cmd->sense_buf_dma,
> + sense_len, DMA_TO_DEVICE);
> + ib_dma_sync_single_for_device(ib_dev, isert_cmd->sense_buf_dma,
> + sense_len, DMA_TO_DEVICE);
> +

you just called dma_map_single, and not going to touch the buffer before
posting it to the wire,
there's no point to sync it for the cpu and for the device, remove these
calls.

> + tx_dsg->addr = isert_cmd->sense_buf_dma;
> + tx_dsg->length = sense_len;
> + tx_dsg->lkey = isert_conn->conn_mr->lkey;
> + isert_cmd->tx_desc.num_sge = 2;
> + }
> +
> + isert_init_send_wr(isert_cmd, send_wr);
> +
> + pr_debug("Posting SCSI Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");
> +
> + return isert_post_response(isert_conn, isert_cmd);
> +}