diff --git a/lib/iscsi/iscsi.c b/lib/iscsi/iscsi.c
index 7c652ddc3..d100b4405 100644
--- a/lib/iscsi/iscsi.c
+++ b/lib/iscsi/iscsi.c
@@ -468,8 +468,10 @@ spdk_iscsi_read_pdu(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu **_pdu)
 		if (pdu->data_buf == NULL) {
 			if (data_len <= spdk_get_immediate_data_buffer_size()) {
 				pool = g_spdk_iscsi.pdu_immediate_data_pool;
+				pdu->data_buf_len = spdk_get_immediate_data_buffer_size();
 			} else if (data_len <= SPDK_ISCSI_MAX_RECV_DATA_SEGMENT_LENGTH) {
 				pool = g_spdk_iscsi.pdu_data_out_pool;
+				pdu->data_buf_len = SPDK_ISCSI_MAX_RECV_DATA_SEGMENT_LENGTH;
 			} else {
 				SPDK_ERRLOG("Data(%d) > MaxSegment(%d)\n",
 					    data_len, SPDK_ISCSI_MAX_RECV_DATA_SEGMENT_LENGTH);
@@ -2595,6 +2597,7 @@ spdk_iscsi_send_datain(struct spdk_iscsi_conn *conn,
 	rsp_pdu = spdk_get_pdu();
 	rsph = (struct iscsi_bhs_data_in *)&rsp_pdu->bhs;
 	rsp_pdu->data = task->scsi.iovs[0].iov_base + offset;
+	rsp_pdu->data_buf_len = task->scsi.iovs[0].iov_len - offset;
 	rsp_pdu->data_from_mempool = true;
 
 	task_tag = task->tag;
diff --git a/lib/iscsi/iscsi.h b/lib/iscsi/iscsi.h
index 401d7ea5d..2ed6b9fe6 100644
--- a/lib/iscsi/iscsi.h
+++ b/lib/iscsi/iscsi.h
@@ -172,6 +172,7 @@ struct spdk_iscsi_pdu {
 	struct spdk_iscsi_task *task; /* data tied to a task buffer */
 	uint32_t cmd_sn;
 	uint32_t writev_offset;
+	uint32_t data_buf_len;
 	TAILQ_ENTRY(spdk_iscsi_pdu)	tailq;