[PATCH 14/15] scsi: libsas: Keep sas host active until finished some work

[chenxiang <chenxiang66@xxxxxxxxxxxxx>]

From: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>

For those works from event queue, if executing them such as
PORTE_BROADCAST_RCVD when sas host is suspended, it will resume sas host
firstly as SMP IOs are sent in the process. So phyup will occur and it
will call work PORTE_BYTES_DMAED. But the original work (such as
PORTE_BROADCAST_RCVD) and the work PORTE_BYTES_DMAED are in the same
singlethread workqueue, so the complete of original work waits for
the complete of work PORTE_BYTES_DMAED while the complete of work
PORTE_BYTES_DMAED wait for the complete of original and it is blocked.

So call pm_runtime_get_noresume() to keep sas host active until
finished those works.

Signed-off-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
Reviewed-by: John Garry <john.garry@xxxxxxxxxx>
---
 drivers/scsi/libsas/sas_event.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c
index 626ef96b9348..3613b9b315bc 100644
--- a/drivers/scsi/libsas/sas_event.c
+++ b/drivers/scsi/libsas/sas_event.c
@@ -50,8 +50,10 @@ void sas_queue_deferred_work(struct sas_ha_struct *ha)
 	list_for_each_entry_safe(sw, _sw, &ha->defer_q, drain_node) {
 		list_del_init(&sw->drain_node);
 		ret = sas_queue_work(ha, sw);
-		if (ret != 1)
+		if (ret != 1) {
+			pm_runtime_put(ha->dev);
 			sas_free_event(to_asd_sas_event(&sw->work));
+		}
 	}
 	spin_unlock_irq(&ha->lock);
 }
@@ -126,16 +128,22 @@ void sas_enable_revalidation(struct sas_ha_struct *ha)
 static void sas_port_event_worker(struct work_struct *work)
 {
 	struct asd_sas_event *ev = to_asd_sas_event(work);
+	struct asd_sas_phy *phy = ev->phy;
+	struct sas_ha_struct *ha = phy->ha;
 
 	sas_port_event_fns[ev->event](work);
+	pm_runtime_put(ha->dev);
 	sas_free_event(ev);
 }
 
 static void sas_phy_event_worker(struct work_struct *work)
 {
 	struct asd_sas_event *ev = to_asd_sas_event(work);
+	struct asd_sas_phy *phy = ev->phy;
+	struct sas_ha_struct *ha = phy->ha;
 
 	sas_phy_event_fns[ev->event](work);
+	pm_runtime_put(ha->dev);
 	sas_free_event(ev);
 }
 
@@ -170,14 +178,19 @@ int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event,
 	if (!ev)
 		return -ENOMEM;
 
+	/* Call pm_runtime_put() with pairs in sas_port_event_worker() */
+	pm_runtime_get_noresume(ha->dev);
+
 	INIT_SAS_EVENT(ev, sas_port_event_worker, phy, event);
 
 	if (sas_defer_event(phy, ev))
 		return 0;
 
 	ret = sas_queue_event(event, &ev->work, ha);
-	if (ret != 1)
+	if (ret != 1) {
+		pm_runtime_put(ha->dev);
 		sas_free_event(ev);
+	}
 
 	return ret;
 }
@@ -196,14 +209,19 @@ int sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event,
 	if (!ev)
 		return -ENOMEM;
 
+	/* Call pm_runtime_put() with pairs in sas_phy_event_worker() */
+	pm_runtime_get_noresume(ha->dev);
+
 	INIT_SAS_EVENT(ev, sas_phy_event_worker, phy, event);
 
 	if (sas_defer_event(phy, ev))
 		return 0;
 
 	ret = sas_queue_event(event, &ev->work, ha);
-	if (ret != 1)
+	if (ret != 1) {
+		pm_runtime_put(ha->dev);
 		sas_free_event(ev);
+	}
 
 	return ret;
 }
-- 
2.33.0