| From 97819f943063b622eca44d3644067c190dc75039 Mon Sep 17 00:00:00 2001 |
| From: Wolfgang Grandegger <wg@grandegger.com> |
| Date: Thu, 14 Sep 2017 18:37:14 +0200 |
| Subject: can: gs_usb: fix busy loop if no more TX context is available |
| |
| From: Wolfgang Grandegger <wg@grandegger.com> |
| |
| 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@grandegger.com> |
| Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| 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) |
