From a03e828915c00ed0ea5aa40647c81472cfa7a984 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <mika.westerberg@linux.intel.com>
Date: Thu, 18 Jan 2018 20:27:47 +0300
Subject: [PATCH] thunderbolt: Serialize PCIe tunnel creation with PCI rescan
Git-commit: a03e828915c00ed0ea5aa40647c81472cfa7a984
Patch-mainline: v4.17
References: FATE#324324

We need to make sure a new PCIe tunnel is not created in a middle of
previous PCI rescan because otherwise the rescan code might find too
much and fail to reconfigure devices properly. This is important when
native PCIe hotplug is used. In BIOS assisted hotplug there should be no
such issue.

Fixes: f67cf491175a ("thunderbolt: Add support for Internal Connection Manager (ICM)")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/thunderbolt/switch.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -722,6 +722,13 @@ static int tb_switch_set_authorized(stru
 	 */
 	pci_lock_rescan_remove();
 
+	/*
+	 * Make sure there is no PCIe rescan ongoing when a new PCIe
+	 * tunnel is created. Otherwise the PCIe rescan code might find
+	 * the new tunnel too early.
+	 */
+	pci_lock_rescan_remove();
+
 	switch (val) {
 	/* Approve switch */
 	case 1:
@@ -743,6 +750,8 @@ static int tb_switch_set_authorized(stru
 
 	pci_unlock_rescan_remove();
 
+	pci_unlock_rescan_remove();
+
 	if (!ret) {
 		sw->authorized = val;
 		/* Notify status change to the userspace */