[PATCH 02/19] thunderbolt: Serialize PCIe tunnel creation with PCI rescan

[Anthony Wong]

From: Mika Westerberg <mika.westerberg at linux.intel.com>

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 at linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko at gmail.com>
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: stable at vger.kernel.org
(cherry picked from commit a03e828915c00ed0ea5aa40647c81472cfa7a984)
Signed-off-by: Anthony Wong <anthony.wong at canonical.com>
---
 drivers/thunderbolt/switch.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index da54ace..1cc7978 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -716,6 +716,13 @@ static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
 	if (sw->authorized)
 		goto unlock;
 
+	/*
+	 * 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:
@@ -735,6 +742,8 @@ static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
 		break;
 	}
 
+	pci_unlock_rescan_remove();
+
 	if (!ret) {
 		sw->authorized = val;
 		/* Notify status change to the userspace */
-- 
2.7.4