From 275e517c30ab23d6da332419b6da5e2d5a234891 Mon Sep 17 00:00:00 2001 From: Thomas Pugliese Date: Tue, 16 Sep 2014 16:40:15 -0500 Subject: [PATCH] usb: wusbcore: fix device disconnect on rekey timeout If three or more wireless devices are connected and two of them disconnect between 1-3 seconds apart, it can cause the HWA to disconnect the remaining devices due to failing to see a DN_Alive message from them. This happens because when the HWA detects that the first device is gone, it will attempt to rekey the remaining devices. If one of the devices is not responding because it has also been disconnected but not yet timed out, the synchronous rekey operation running on the wusbd workqueue can block for up to 5 seconds. This will prevent the KEEPALIVE timer from running and DN_Alive messages from being processed because they are processed by the same workqueue. This patch moves the rekey operation to a separate workqueue since it is the only wusb work item that needs to communicate directly with wireless devices. The rest of the WUSB work items either perform no device IO or communicate directly with the host controller and should not be blocked out by a non-responding wireless device. Signed-off-by: Thomas Pugliese Signed-off-by: Greg Kroah-Hartman --- drivers/usb/wusbcore/security.c | 17 ++++++++++++++++- drivers/usb/wusbcore/wusbhc.h | 3 +++ 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/usb/wusbcore/security.c b/drivers/usb/wusbcore/security.c index 95be9953cd47..cc74d669c802 100644 --- a/drivers/usb/wusbcore/security.c +++ b/drivers/usb/wusbcore/security.c @@ -33,6 +33,20 @@ static void wusbhc_gtk_rekey_work(struct work_struct *work); int wusbhc_sec_create(struct wusbhc *wusbhc) { + /* + * WQ is singlethread because we need to serialize rekey operations. + * Use a separate workqueue for security operations instead of the + * wusbd workqueue because security operations may need to communicate + * directly with downstream wireless devices using synchronous URBs. + * If a device is not responding, this could block other host + * controller operations. + */ + wusbhc->wq_security = create_singlethread_workqueue("wusbd_security"); + if (wusbhc->wq_security == NULL) { + pr_err("WUSB-core: Cannot create wusbd_security workqueue\n"); + return -ENOMEM; + } + wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data); wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY; @@ -48,6 +62,7 @@ int wusbhc_sec_create(struct wusbhc *wusbhc) /* Called when the HC is destroyed */ void wusbhc_sec_destroy(struct wusbhc *wusbhc) { + destroy_workqueue(wusbhc->wq_security); } @@ -596,5 +611,5 @@ void wusbhc_gtk_rekey(struct wusbhc *wusbhc) * and will cause a deadlock. Instead, queue a work item to do * it when the lock is not held */ - queue_work(wusbd, &wusbhc->gtk_rekey_work); + queue_work(wusbhc->wq_security, &wusbhc->gtk_rekey_work); } diff --git a/drivers/usb/wusbcore/wusbhc.h b/drivers/usb/wusbcore/wusbhc.h index 2384add45371..41838db7f85c 100644 --- a/drivers/usb/wusbcore/wusbhc.h +++ b/drivers/usb/wusbcore/wusbhc.h @@ -295,6 +295,9 @@ struct wusbhc { } __attribute__((packed)) gtk; u8 gtk_index; u32 gtk_tkid; + + /* workqueue for WUSB security related tasks. */ + struct workqueue_struct *wq_security; struct work_struct gtk_rekey_work; struct usb_encryption_descriptor *ccm1_etd;