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

From: Or Gerlitz
Date: Thu Apr 04 2013 - 05:51:24 EST


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);
+}

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