[PATCH v2 2/2] usb: xhci: fix 'num_active_eps' accounting on allocation failure

[Niklas Neronin <niklas.neronin@linux.intel.com>]

For controllers affected by XHCI_EP_LIMIT_QUIRK, endpoint resources for
the default control endpoint are accounted before the virtual device is
allocated.

If xhci_alloc_virt_device() fails, the slot is disabled and cleanup is
handled through the Disable Slot completion path. However, because no
virtual device is installed in 'xhci->devs', the endpoint accounting
is never released and 'num_active_eps' remains incremented.

As a result, each allocation failure leaks one endpoint from the
driver's accounting.

Fix this by undoing the endpoint reservation when virtual device
allocation fails.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
---
v2:
 * Rework commit message

 drivers/usb/host/xhci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 0361dfaecdd7..394f69b3cfbf 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4279,6 +4279,11 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
 	 */
 	if (!xhci_alloc_virt_device(xhci, slot_id, udev, GFP_NOIO)) {
 		xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
+		if (xhci->quirks & XHCI_EP_LIMIT_QUIRK) {
+			spin_lock_irqsave(&xhci->lock, flags);
+			xhci->num_active_eps -= 1;
+			spin_unlock_irqrestore(&xhci->lock, flags);
+		}
 		goto disable_slot;
 	}
 	vdev = xhci->devs[slot_id];
-- 
2.50.1