[PATCH v1 09/17] thunderbolt: Switch to use acpi_bus_get_primary_device()

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>

Replace acpi_get_first_physical_node() that is slated for removal
with acpi_bus_get_primary_device() that takes a reference to the
device it is about to return.

This addresses a potential use-after-free that may occur if the
device returned by acpi_get_first_physical_node() is removed right
after dropping its ACPI companion's physical_node_lock in that
function.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
---
 drivers/thunderbolt/acpi.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/acpi.c b/drivers/thunderbolt/acpi.c
index 53546bc477a5..be91bc604900 100644
--- a/drivers/thunderbolt/acpi.c
+++ b/drivers/thunderbolt/acpi.c
@@ -17,8 +17,8 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
 	struct fwnode_handle *fwnode;
 	struct tb_nhi *nhi = data;
+	struct device *dev = NULL;
 	struct pci_dev *pdev;
-	struct device *dev;
 
 	if (!adev)
 		return AE_OK;
@@ -37,7 +37,7 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
 	 * USB3 ports might not even have a physical device yet if xHCI driver
 	 * isn't bound yet.
 	 */
-	dev = acpi_get_first_physical_node(adev);
+	dev = acpi_bus_get_primary_device(adev);
 	if (!dev || !dev_is_pci(dev))
 		goto out_put;
 
@@ -74,6 +74,7 @@ static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
 	}
 
 out_put:
+	put_device(dev);
 	fwnode_handle_put(fwnode);
 	return AE_OK;
 }
-- 
2.51.0