[PATCH 86/88] USB: Prepare for refactoring by adding extra udev checks.

[Luis Henriques]

3.5.7.8 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>

commit 2d4fa940f99663c82ba55b2244638833b388e4e2 upstream.

[This is upstream commit 2d4fa940f99663c82ba55b2244638833b388e4e2.
It needs to be backported to kernels as old as 3.2, because it fixes the
buggy commit 9dbcaec830cd97f44a0b91b315844e0d7144746b "USB: Handle warm
reset failure on empty port."]

The next patch will refactor the hub port code to rip out the recursive
call to hub_port_reset on a failed hot reset.  In preparation for that,
make sure all code paths can deal with being called with a NULL udev.
The usb_device will not be valid if warm reset was issued because a port
transitioned to the Inactive or Compliance Mode on a device connect.

This patch should have no effect on current behavior.

Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 drivers/usb/core/hub.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1a2cd0e..15b6be0 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2475,6 +2475,9 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
 				return -ENOTCONN;
 
 			if ((portstatus & USB_PORT_STAT_ENABLE)) {
+				if (!udev)
+					return 0;
+
 				if (hub_is_wusb(hub))
 					udev->speed = USB_SPEED_WIRELESS;
 				else if (hub_is_superspeed(hub->hdev))
@@ -2518,13 +2521,15 @@ static void hub_port_finish_reset(struct usb_hub *hub, int port1,
 			struct usb_hcd *hcd;
 			/* TRSTRCY = 10 ms; plus some extra */
 			msleep(10 + 40);
-			update_devnum(udev, 0);
-			hcd = bus_to_hcd(udev->bus);
-			/* The xHC may think the device is already reset,
-			 * so ignore the status.
-			 */
-			if (hcd->driver->reset_device)
-				hcd->driver->reset_device(hcd, udev);
+			if (udev) {
+				update_devnum(udev, 0);
+				hcd = bus_to_hcd(udev->bus);
+				/* The xHC may think the device is already
+				 * reset, so ignore the status.
+				 */
+				if (hcd->driver->reset_device)
+					hcd->driver->reset_device(hcd, udev);
+			}
 		}
 		/* FALL THROUGH */
 	case -ENOTCONN:
@@ -2538,7 +2543,7 @@ static void hub_port_finish_reset(struct usb_hub *hub, int port1,
 			clear_port_feature(hub->hdev, port1,
 					USB_PORT_FEAT_C_PORT_LINK_STATE);
 		}
-		if (!warm)
+		if (!warm && udev)
 			usb_set_device_state(udev, *status
 					? USB_STATE_NOTATTACHED
 					: USB_STATE_DEFAULT);
-- 
1.8.1.2

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