Commit fcccc160 authored by Shuhei Matsumoto's avatar Shuhei Matsumoto Committed by Tomasz Zawadzki
Browse files

lib/iscsi: Factor out SCSI write payload handling into a single function 



We want to move iSCSI task allocation before data buffer allocation
to use zero copy APIs in iSCSI target. As a preparation, we have to
separate PDU header and payload handling. This patch makes it a little
easier.

Signed-off-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: Ib7f5ec71933fd6022fd2248aff0a0bd89b7ad830
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/470289


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
Reviewed-by: default avatarPaul Luse <paul.e.luse@intel.com>
parent e6d090dd

lib/iscsi/iscsi.c

+54 −35
Original line number Diff line number Diff line
@@ -3298,6 +3298,57 @@ iscsi_op_scsi_read(struct spdk_iscsi_conn *conn, struct spdk_iscsi_task *task) 
	return spdk_iscsi_conn_handle_queued_datain_tasks(conn);

}



static int

iscsi_op_scsi_write(struct spdk_iscsi_conn *conn, struct spdk_iscsi_task *task)

{

	struct spdk_iscsi_pdu *pdu;

	struct iscsi_bhs_scsi_req *reqh;

	uint32_t transfer_len;

	uint32_t scsi_data_len;

	int rc;



	pdu = spdk_iscsi_task_get_pdu(task);

	reqh = (struct iscsi_bhs_scsi_req *)&pdu->bhs;



	transfer_len = task->scsi.transfer_len;



	if (spdk_likely(!pdu->dif_insert_or_strip)) {

		scsi_data_len = pdu->data_segment_len;

	} else {

		scsi_data_len = pdu->data_buf_len;

	}



	if (reqh->final_bit &&

	    pdu->data_segment_len < transfer_len) {

		/* needs R2T */

		rc = add_transfer_task(conn, task);

		if (rc < 0) {

			SPDK_ERRLOG("add_transfer_task() failed\n");

			spdk_iscsi_task_put(task);

			return SPDK_ISCSI_CONNECTION_FATAL;

		}



		/* Non-immediate writes */

		if (pdu->data_segment_len == 0) {

			return 0;

		} else {

			/* we are doing the first partial write task */

			task->scsi.ref++;

			spdk_scsi_task_set_data(&task->scsi, pdu->data, scsi_data_len);

			task->scsi.length = pdu->data_segment_len;

		}

	}



	if (pdu->data_segment_len == transfer_len) {

		/* we are doing small writes with no R2T */

		spdk_scsi_task_set_data(&task->scsi, pdu->data, scsi_data_len);

		task->scsi.length = transfer_len;

	}



	iscsi_queue_task(conn, task);

	return 0;

}



static int

iscsi_op_scsi(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)

{
@@ -3307,9 +3358,8 @@ iscsi_op_scsi(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu) 
	uint64_t lun;

	uint32_t task_tag;

	uint32_t transfer_len;

	uint32_t scsi_data_len;

	int F_bit, R_bit, W_bit;

	int lun_i, rc;

	int R_bit, W_bit;

	int lun_i;

	struct iscsi_bhs_scsi_req *reqh;



	if (conn->sess->session_type != SESSION_TYPE_NORMAL) {
@@ -3319,7 +3369,6 @@ iscsi_op_scsi(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu) 


	reqh = (struct iscsi_bhs_scsi_req *)&pdu->bhs;



	F_bit = reqh->final_bit;

	R_bit = reqh->read_bit;

	W_bit = reqh->write_bit;

	lun = from_be64(&reqh->lun);
@@ -3395,37 +3444,7 @@ iscsi_op_scsi(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu) 
			return iscsi_reject(conn, pdu, ISCSI_REASON_PROTOCOL_ERROR);

		}



		if (spdk_likely(!pdu->dif_insert_or_strip)) {

			scsi_data_len = pdu->data_segment_len;

		} else {

			scsi_data_len = pdu->data_buf_len;

		}



		if (F_bit && pdu->data_segment_len < transfer_len) {

			/* needs R2T */

			rc = add_transfer_task(conn, task);

			if (rc < 0) {

				SPDK_ERRLOG("add_transfer_task() failed\n");

				spdk_iscsi_task_put(task);

				return SPDK_ISCSI_CONNECTION_FATAL;

			}



			/* Non-immediate writes */

			if (pdu->data_segment_len == 0) {

				return 0;

			} else {

				/* we are doing the first partial write task */

				task->scsi.ref++;

				spdk_scsi_task_set_data(&task->scsi, pdu->data, scsi_data_len);

				task->scsi.length = pdu->data_segment_len;

			}

		}



		if (pdu->data_segment_len == transfer_len) {

			/* we are doing small writes with no R2T */

			spdk_scsi_task_set_data(&task->scsi, pdu->data, scsi_data_len);

			task->scsi.length = transfer_len;

		}

		return iscsi_op_scsi_write(conn, task);

	} else {

		/* neither R nor W bit set */

		task->scsi.dxfer_dir = SPDK_SCSI_DIR_NONE;