An URB submission error in the HUB's endpoint completion function
renders the whole HUB device unresponsive. This patch introduces a
routine that retries the submission for 1s to then, as a last resort,
reset the whole device.
The implementation is based on usbhid/hid_core.c's, which implements the
same functionality. It was tested with the help of BCC's error injection
tool (inject.py).
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
---
drivers/usb/core/hub.c | 43 +++++++++++++++++++++++++++++++++++++++++-
drivers/usb/core/hub.h | 3 +++
2 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d9bd7576786a..1447bdba59ec 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -607,6 +607,44 @@ static int hub_port_status(struct usb_hub *hub, int port1,
status, change, NULL);
}
+static void hub_io_error(struct usb_hub *hub)
+{
+ /*
+ * If it has been a while since the last error, we'll assume
+ * this a brand new error and reset the retry timeout.
+ */
+ if (time_after(jiffies, hub->stop_retry + HZ/2))
+ hub->retry_delay = 0;
+
+ /* When an error occurs, retry at increasing intervals */
+ if (hub->retry_delay == 0) {
+ hub->retry_delay = 13; /* Then 26, 52, 104, 104, ... */
+ hub->stop_retry = jiffies + msecs_to_jiffies(1000);
+ } else if (hub->retry_delay < 100)
+ hub->retry_delay *= 2;
+
+ if (time_after(jiffies, hub->stop_retry)) {
+ /* Retries failed, so do a port reset */
+ usb_queue_reset_device(to_usb_interface(hub->intfdev));
+ return;
+ }
+
+ mod_timer(&hub->io_retry,
+ jiffies + msecs_to_jiffies(hub->retry_delay));
+}
+
+static void hub_retry_timeout(struct timer_list *t)
+{
+ struct usb_hub *hub = from_timer(hub, t, io_retry);
+
+ if (hub->disconnected || hub->quiescing)
+ return;
+
+ dev_err(hub->intfdev, "retrying int urb\n");
+ if (usb_submit_urb(hub->urb, GFP_ATOMIC))
+ hub_io_error(hub);
+}
+
static void kick_hub_wq(struct usb_hub *hub)
{
struct usb_interface *intf;
@@ -713,8 +751,10 @@ static void hub_irq(struct urb *urb)
return;
status = usb_submit_urb(hub->urb, GFP_ATOMIC);
- if (status != 0 && status != -ENODEV && status != -EPERM)
+ if (status != 0 && status != -ENODEV && status != -EPERM) {
dev_err(hub->intfdev, "resubmit --> %d\n", status);
+ hub_io_error(hub);
+ }
}
/* USB 2.0 spec Section 11.24.2.3 */
@@ -1800,6 +1840,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
INIT_DELAYED_WORK(&hub->leds, led_work);
INIT_DELAYED_WORK(&hub->init_work, NULL);
INIT_WORK(&hub->events, hub_event);
+ timer_setup(&hub->io_retry, hub_retry_timeout, 0);
usb_get_intf(intf);
usb_get_dev(hdev);
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 4accfb63f7dc..7dbd19c2c8d9 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -69,6 +69,9 @@ struct usb_hub {
struct delayed_work leds;
struct delayed_work init_work;
struct work_struct events;
+ struct timer_list io_retry;
+ unsigned long stop_retry;
+ unsigned int retry_delay;
struct usb_port **ports;
};
--
2.19.1
