[PATCH 06/11] smartpqi: correct hang when deleting 32 lds

[Don Brace <don.brace@xxxxxxxxxxxxx>]

From: Mahesh Rajashekhara <mahesh.rajashekhara@xxxxxxxxxxxxx>

 - when each ld is deleted, a rescan event is triggered
   in the driver. These can stack up waiting on
   mutex_lock.
 - change to mutex_try_lock and schedule a rescan
   for later.

Reviewed-by: Scott Benesh <scott.benesh@xxxxxxxxxxxxx>
Reviewed-by: Kevin Barnett <kevin.barnett@xxxxxxxxxxxxx>
Signed-off-by: Mahesh Rajashekhara <mahesh.rajashekhara@xxxxxxxxxxxxx>
Signed-off-by: Don Brace <don.brace@xxxxxxxxxxxxx>
---
 drivers/scsi/smartpqi/smartpqi_init.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index a6cb49b8e5d0..9801606dadfa 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -2236,18 +2236,20 @@ static void pqi_remove_all_scsi_devices(struct pqi_ctrl_info *ctrl_info)
 
 static int pqi_scan_scsi_devices(struct pqi_ctrl_info *ctrl_info)
 {
-	int rc;
+	int rc = 0;
 
 	if (pqi_ctrl_offline(ctrl_info))
 		return -ENXIO;
 
-	mutex_lock(&ctrl_info->scan_mutex);
-
-	rc = pqi_update_scsi_devices(ctrl_info);
-	if (rc)
+	if (!mutex_trylock(&ctrl_info->scan_mutex)) {
 		pqi_schedule_rescan_worker_delayed(ctrl_info);
 
-	mutex_unlock(&ctrl_info->scan_mutex);
+	} else {
+		rc = pqi_update_scsi_devices(ctrl_info);
+		if (rc)
+			pqi_schedule_rescan_worker_delayed(ctrl_info);
+		mutex_unlock(&ctrl_info->scan_mutex);
+	}
 
 	return rc;
 }