Take g_ncm for instance. It enqueues a few BULK URBs on receive side and an INTR URB. Now we remove the g_ncm module. This starts with usb_gadget_disconnect() which disables the UDC. Now lets say the timer expires and dummy_timer() is invoked. It can't find a pair between the UDC endpoint and URB's address in find_endpoint() because the is_active() is no longer true. So we start a cleanup of URBs. The BULK URBs usually don't make a scene. They re-submit the complete queue length in BH so we have a little time in between. The INTR URB is more evil because usbnet's intr_complete() causes to re-submitt it immediately. That means we hardly do any progress and end up in a busy loop. This patch changes the status code for URBs which can not be assigned to an endpoint (because the UDC is in pulldown) are now given back with -ESHUTDOWN. The BULK endpoints in ncm are re-submitted in batches of 10 in BH but the INTR URB will never be re-submitted. This gives us somes air to make some progress and remove the gadget.
An alternative approach would be to not accept any new URBs once the port is not active. Something similar is already done on the UDC side. Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- drivers/usb/gadget/dummy_hcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/gadget/dummy_hcd.c b/drivers/usb/gadget/dummy_hcd.c index afdbb1c..dfb2f0d 100644 --- a/drivers/usb/gadget/dummy_hcd.c +++ b/drivers/usb/gadget/dummy_hcd.c @@ -1740,7 +1740,7 @@ restart: dev_dbg(dummy_dev(dum_hcd), "no ep configured for urb %p\n", urb); - status = -EPROTO; + status = -ESHUTDOWN; goto return_urb; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
