Commit 9c5a3a1f authored Mar 14, 2017 by Shannon Nelson Committed by David S. Miller Mar 16, 2017

sunvnet: xoff not needed when removing port link



The sunvnet netdev is connected to the controlling ldom's vswitch
for network bridging.  However, for higher performance between ldoms,
there also is a channel between each client ldom.  These connections are
represented in the sunvnet driver by a queue for each ldom.  The driver
uses select_queue to tell the stack which queue to use by tracking the mac
addresses on the other end of each port.  When a connected ldom shuts down,
the driver receives an LDC_EVENT_RESET and the port is removed from the
driver, thus a queue with no ldom on the other end will never be selected
for Tx.

The driver was trying to reinforce the "don't use this queue" notion with
netif_tx_stop_queue() and netif_tx_wake_queue(), which really should only
be used to signal a Tx queue is full (aka XOFF).  This misuse of queue
state resulted in NETDEV WATCHDOG messages and lots of unnecessary calls
into the driver's tx_timeout handler.  Simply removing these takes care
of the problem.

Orabug: 25190537

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b12a96f5

drivers/net/ethernet/sun/sunvnet_common.c

+0 −4

Original line number	Diff line number	Diff line
		@@ -1749,16 +1749,12 @@ void sunvnet_port_add_txq_common(struct vnet_port *port)
		vp->nports++;
		vp->q_used[smallest]++;
		port->q_index = smallest;
		netif_tx_wake_queue(netdev_get_tx_queue(VNET_PORT_TO_NET_DEVICE(port),
		port->q_index));
		}
		EXPORT_SYMBOL_GPL(sunvnet_port_add_txq_common);

		void sunvnet_port_rm_txq_common(struct vnet_port *port)
		{
		port->vp->nports--;
		netif_tx_stop_queue(netdev_get_tx_queue(VNET_PORT_TO_NET_DEVICE(port),
		port->q_index));
		port->vp->q_used[port->q_index]--;
		port->q_index = 0;
		}