Patch "scsi: hpsa: limit outstanding rescans" has been added to the 4.9-stable tree

@@ -5529,7 +5529,7 @@ static void hpsa_scan_complete(struct ct
 
 	spin_lock_irqsave(&h->scan_lock, flags);
 	h->scan_finished = 1;
-	wake_up_all(&h->scan_wait_queue);
+	wake_up(&h->scan_wait_queue);
 	spin_unlock_irqrestore(&h->scan_lock, flags);
 }
 

@@ -5547,11 +5547,23 @@ static void hpsa_scan_start(struct Scsi_
 	if (unlikely(lockup_detected(h)))
 		return hpsa_scan_complete(h);
 
+	/*
+	 * If a scan is already waiting to run, no need to add another
+	 */
+	spin_lock_irqsave(&h->scan_lock, flags);
+	if (h->scan_waiting) {
+		spin_unlock_irqrestore(&h->scan_lock, flags);
+		return;
+	}
+
+	spin_unlock_irqrestore(&h->scan_lock, flags);
+
 	/* wait until any scan already in progress is finished. */
 	while (1) {
 		spin_lock_irqsave(&h->scan_lock, flags);
 		if (h->scan_finished)
 			break;
+		h->scan_waiting = 1;
 		spin_unlock_irqrestore(&h->scan_lock, flags);
 		wait_event(h->scan_wait_queue, h->scan_finished);
 		/* Note: We don't need to worry about a race between this

@@ -5561,6 +5573,7 @@ static void hpsa_scan_start(struct Scsi_
 		 */
 	}
 	h->scan_finished = 0; /* mark scan as in progress */
+	h->scan_waiting = 0;
 	spin_unlock_irqrestore(&h->scan_lock, flags);
 
 	if (unlikely(lockup_detected(h)))

@@ -8799,6 +8812,7 @@ reinit_after_soft_reset:
 	init_waitqueue_head(&h->event_sync_wait_queue);
 	mutex_init(&h->reset_mutex);
 	h->scan_finished = 1; /* no scan currently in progress */
+	h->scan_waiting = 0;
 
 	pci_set_drvdata(pdev, h);
 	h->ndevices = 0;

@@ -203,6 +203,7 @@ struct ctlr_info {
 	dma_addr_t		errinfo_pool_dhandle;
 	unsigned long  		*cmd_pool_bits;
 	int			scan_finished;
+	u8			scan_waiting : 1;
 	spinlock_t		scan_lock;
 	wait_queue_head_t	scan_wait_queue;