Commit 65080c51 authored by Dmitry Bogdanov's avatar Dmitry Bogdanov Committed by Martin K. Petersen
Browse files

scsi: iscsi: Prefer xmit of DataOut over new commands 

iscsi_data_xmit() (TX worker) is iterating over the queue of new SCSI
commands concurrently with the queue being replenished. Only after the
queue is emptied will we start sending pending DataOut PDUs. That leads to
DataOut timeout on the target side and to connection reinstatement.

Give priority to pending DataOut commands over new commands.

Link: https://lore.kernel.org/r/20220607131953.11584-1-d.bogdanov@yadro.com


Reviewed-by: default avatarKonstantin Shelekhin <k.shelekhin@yadro.com>
Reviewed-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarDmitry Bogdanov <d.bogdanov@yadro.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent c0d93b12

drivers/scsi/libiscsi.c

+24 −20
Original line number Diff line number Diff line
@@ -1567,6 +1567,28 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
			goto done;

	}



check_requeue:

	while (!list_empty(&conn->requeue)) {

		/*

		 * we always do fastlogout - conn stop code will clean up.

		 */

		if (conn->session->state == ISCSI_STATE_LOGGING_OUT)

			break;



		task = list_entry(conn->requeue.next, struct iscsi_task,

				  running);



		if (iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_DATA_OUT))

			break;



		list_del_init(&task->running);

		rc = iscsi_xmit_task(conn, task, true);

		if (rc)

			goto done;

		if (!list_empty(&conn->mgmtqueue))

			goto check_mgmt;

	}



	/* process pending command queue */

	while (!list_empty(&conn->cmdqueue)) {

		task = list_entry(conn->cmdqueue.next, struct iscsi_task,
@@ -1594,28 +1616,10 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
		 */

		if (!list_empty(&conn->mgmtqueue))

			goto check_mgmt;

		if (!list_empty(&conn->requeue))

			goto check_requeue;

	}



	while (!list_empty(&conn->requeue)) {

		/*

		 * we always do fastlogout - conn stop code will clean up.

		 */

		if (conn->session->state == ISCSI_STATE_LOGGING_OUT)

			break;



		task = list_entry(conn->requeue.next, struct iscsi_task,

				  running);



		if (iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_DATA_OUT))

			break;



		list_del_init(&task->running);

		rc = iscsi_xmit_task(conn, task, true);

		if (rc)

			goto done;

		if (!list_empty(&conn->mgmtqueue))

			goto check_mgmt;

	}

	spin_unlock_bh(&conn->session->frwd_lock);

	return -ENODATA;