[PATCH 04/13] qla2xxx: Fix session cleanup hang

[Himanshu Madhani <hmadhani@xxxxxxxxxxx>]

From: Quinn Tran <quinn.tran@xxxxxxxxxx>

On session cleanup, either an implicit LOGO or an implicit PRLO
is used to flush IOs.  If the flush command hit Queue Full condition,
then it is dropped.  This patch adds retry code to prevent command drop.

Signed-off-by: Quinn Tran <quinn.tran@xxxxxxxxxx>
Signed-off-by: Himanshu Madhani <hmadhani@xxxxxxxxxxx>
---
 drivers/scsi/qla2xxx/qla_iocb.c |  5 ++---
 drivers/scsi/qla2xxx/qla_os.c   | 17 +++++++++++++----
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 032635321ad6..97fea5984db3 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -3434,23 +3434,22 @@ qla24xx_prlo_iocb(srb_t *sp, struct logio_entry_24xx *logio)
 int
 qla2x00_start_sp(srb_t *sp)
 {
-	int rval;
+	int rval = QLA_SUCCESS;
 	scsi_qla_host_t *vha = sp->vha;
 	struct qla_hw_data *ha = vha->hw;
 	struct qla_qpair *qp = sp->qpair;
 	void *pkt;
 	unsigned long flags;
 
-	rval = QLA_FUNCTION_FAILED;
 	spin_lock_irqsave(qp->qp_lock_ptr, flags);
 	pkt = __qla2x00_alloc_iocbs(sp->qpair, sp);
 	if (!pkt) {
+		rval = EAGAIN;
 		ql_log(ql_log_warn, vha, 0x700c,
 		    "qla2x00_alloc_iocbs failed.\n");
 		goto done;
 	}
 
-	rval = QLA_SUCCESS;
 	switch (sp->type) {
 	case SRB_LOGIN_CMD:
 		IS_FWI2_CAPABLE(ha) ?
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 39a0bdb66612..f9cbf73bb417 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -5019,14 +5019,14 @@ qla2x00_do_work(struct scsi_qla_host *vha)
 	struct qla_work_evt *e, *tmp;
 	unsigned long flags;
 	LIST_HEAD(work);
+	int rc;
 
 	spin_lock_irqsave(&vha->work_lock, flags);
 	list_splice_init(&vha->work_list, &work);
 	spin_unlock_irqrestore(&vha->work_lock, flags);
 
 	list_for_each_entry_safe(e, tmp, &work, list) {
-		list_del_init(&e->list);
-
+		rc = QLA_SUCCESS;
 		switch (e->type) {
 		case QLA_EVT_AEN:
 			fc_host_post_event(vha->host, fc_get_event_number(),
@@ -5040,7 +5040,7 @@ qla2x00_do_work(struct scsi_qla_host *vha)
 			    e->u.logio.data);
 			break;
 		case QLA_EVT_ASYNC_LOGOUT:
-			qla2x00_async_logout(vha, e->u.logio.fcport);
+			rc = qla2x00_async_logout(vha, e->u.logio.fcport);
 			break;
 		case QLA_EVT_ASYNC_LOGOUT_DONE:
 			qla2x00_async_logout_done(vha, e->u.logio.fcport,
@@ -5085,7 +5085,7 @@ qla2x00_do_work(struct scsi_qla_host *vha)
 			qla24xx_do_nack_work(vha, e);
 			break;
 		case QLA_EVT_ASYNC_PRLO:
-			qla2x00_async_prlo(vha, e->u.logio.fcport);
+			rc = qla2x00_async_prlo(vha, e->u.logio.fcport);
 			break;
 		case QLA_EVT_ASYNC_PRLO_DONE:
 			qla2x00_async_prlo_done(vha, e->u.logio.fcport,
@@ -5118,6 +5118,15 @@ qla2x00_do_work(struct scsi_qla_host *vha)
 			    e->u.fcport.fcport, false);
 			break;
 		}
+
+		if (rc == EAGAIN) {
+			/* put 'work' at head of 'vha->work_list' */
+			spin_lock_irqsave(&vha->work_lock, flags);
+			list_splice(&work, &vha->work_list);
+			spin_unlock_irqrestore(&vha->work_lock, flags);
+			break;
+		}
+		list_del_init(&e->list);
 		if (e->flags & QLA_EVT_FLAG_FREE)
 			kfree(e);
 
-- 
2.12.0