[PATCH 3/7] qla2xxx: Fix task management cmd fail due to unavailable resource

[Nilesh Javali <njavali@xxxxxxxxxxx>]

From: Quinn Tran <qutran@xxxxxxxxxxx>

Task management command failed with status 2Ch which is
a result of too many task management commands sent
to the same target. Hence limit task management commands
to 8 per target.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Quinn Tran <qutran@xxxxxxxxxxx>
Signed-off-by: Nilesh Javali <njavali@xxxxxxxxxxx>
---
 drivers/scsi/qla2xxx/qla_def.h  |  3 ++
 drivers/scsi/qla2xxx/qla_init.c | 63 ++++++++++++++++++++++++++++++---
 2 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index 0437e0150a50..0971150953a9 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -2543,6 +2543,7 @@ enum rscn_addr_format {
 typedef struct fc_port {
 	struct list_head list;
 	struct scsi_qla_host *vha;
+	struct list_head tmf_pending;
 
 	unsigned int conf_compl_supported:1;
 	unsigned int deleted:2;
@@ -2563,6 +2564,8 @@ typedef struct fc_port {
 	unsigned int do_prli_nvme:1;
 
 	uint8_t nvme_flag;
+	uint8_t active_tmf;
+#define MAX_ACTIVE_TMF 8
 
 	uint8_t node_name[WWN_SIZE];
 	uint8_t port_name[WWN_SIZE];
diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
index 45a941409fef..9920a3b821b0 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -2149,6 +2149,54 @@ __qla2x00_async_tm_cmd(struct tmf_arg *arg)
 	return rval;
 }
 
+void qla_put_tmf(fc_port_t *fcport)
+{
+	struct scsi_qla_host *vha = fcport->vha;
+	struct qla_hw_data *ha = vha->hw;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ha->tgt.sess_lock, flags);
+	fcport->active_tmf--;
+	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
+}
+
+static
+int qla_get_tmf(fc_port_t *fcport)
+{
+	struct scsi_qla_host *vha = fcport->vha;
+	struct qla_hw_data *ha = vha->hw;
+	unsigned long flags;
+	int rc = 0;
+	LIST_HEAD(tmf_elem);
+
+	spin_lock_irqsave(&ha->tgt.sess_lock, flags);
+	list_add_tail(&tmf_elem, &fcport->tmf_pending);
+
+	while (fcport->active_tmf >= MAX_ACTIVE_TMF) {
+		spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
+
+		msleep(1);
+
+		spin_lock_irqsave(&ha->tgt.sess_lock, flags);
+		if (fcport->deleted) {
+			rc = EIO;
+			break;
+		}
+		if (fcport->active_tmf < MAX_ACTIVE_TMF &&
+		    list_is_first(&tmf_elem, &fcport->tmf_pending))
+			break;
+	}
+
+	list_del(&tmf_elem);
+
+	if (!rc)
+		fcport->active_tmf++;
+
+	spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
+
+	return rc;
+}
+
 int
 qla2x00_async_tm_cmd(fc_port_t *fcport, uint32_t flags, uint64_t lun,
 		     uint32_t tag)
@@ -2156,18 +2204,19 @@ qla2x00_async_tm_cmd(fc_port_t *fcport, uint32_t flags, uint64_t lun,
 	struct scsi_qla_host *vha = fcport->vha;
 	struct qla_qpair *qpair;
 	struct tmf_arg a;
-	struct completion comp;
 	int i, rval;
 
-	init_completion(&comp);
 	a.vha = fcport->vha;
 	a.fcport = fcport;
 	a.lun = lun;
-
-	if (flags & (TCF_LUN_RESET|TCF_ABORT_TASK_SET| TCF_CLEAR_TASK_SET|TCF_CLEAR_ACA))
+	if (flags & (TCF_LUN_RESET|TCF_ABORT_TASK_SET| TCF_CLEAR_TASK_SET|TCF_CLEAR_ACA)) {
 		a.modifier = MK_SYNC_ID_LUN;
-	else
+
+		if (qla_get_tmf(fcport))
+			return QLA_FUNCTION_FAILED;
+	} else {
 		a.modifier = MK_SYNC_ID;
+	}
 
 	if (vha->hw->mqenable) {
 		for (i = 0; i < vha->hw->num_qpairs; i++) {
@@ -2186,6 +2235,9 @@ qla2x00_async_tm_cmd(fc_port_t *fcport, uint32_t flags, uint64_t lun,
 	a.flags = flags;
 	rval = __qla2x00_async_tm_cmd(&a);
 
+	if (a.modifier == MK_SYNC_ID_LUN)
+		qla_put_tmf(fcport);
+
 	return rval;
 }
 
@@ -5400,6 +5452,7 @@ qla2x00_alloc_fcport(scsi_qla_host_t *vha, gfp_t flags)
 	INIT_WORK(&fcport->reg_work, qla_register_fcport_fn);
 	INIT_LIST_HEAD(&fcport->gnl_entry);
 	INIT_LIST_HEAD(&fcport->list);
+	INIT_LIST_HEAD(&fcport->tmf_pending);
 
 	INIT_LIST_HEAD(&fcport->sess_cmd_list);
 	spin_lock_init(&fcport->sess_cmd_lock);
-- 
2.23.1