3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx> commit 97819f943063b622eca44d3644067c190dc75039 upstream. If sending messages with no cable connected, it quickly happens that there is no more TX context available. Then "gs_can_start_xmit()" returns with "NETDEV_TX_BUSY" and the upper layer does retry immediately keeping the CPU busy. To fix that issue, I moved "atomic_dec(&dev->active_tx_urbs)" from "gs_usb_xmit_callback()" to the TX done handling in "gs_usb_receive_bulk_callback()". Renaming "active_tx_urbs" to "active_tx_contexts" and moving it into "gs_[alloc|free]_tx_context()" would also make sense. Signed-off-by: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/can/usb/gs_usb.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -356,6 +356,8 @@ static void gs_usb_recieve_bulk_callback gs_free_tx_context(txc); + atomic_dec(&dev->active_tx_urbs); + netif_wake_queue(netdev); } @@ -444,14 +446,6 @@ static void gs_usb_xmit_callback(struct urb->transfer_buffer_length, urb->transfer_buffer, urb->transfer_dma); - - atomic_dec(&dev->active_tx_urbs); - - if (!netif_device_present(netdev)) - return; - - if (netif_queue_stopped(netdev)) - netif_wake_queue(netdev); } static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb, struct net_device *netdev)