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Commit d21385fa authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'sunvnet-next' 



Sowmini Varadhan says:

====================
sunvnet: edge-case/race-conditions bug fixes

This patch series contains fixes for race-conditions in sunvnet,
that can encountered when there is a difference in latency between
producer and consumer.

Patch 1 addresses a case when the STOPPED LDC ack from a peer is
processed before vnet_start_xmit can finish updating the dr->prod
state.

Patch 2 fixes the edge-case when outgoing data and incoming
stopped-ack cross each other in flight.

Patch 3 adds a missing rcu_read_unlock(), found by code-inspection.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 6f6e741f df20286a

drivers/net/ethernet/sun/sunvnet.c

+10 −6
Original line number Original line Diff line number Diff line
@@ -559,18 +559,20 @@ static int vnet_ack(struct vnet_port *port, void *msgbuf) 
		return 0;

		return 0;





	end = pkt->end_idx;

	end = pkt->end_idx;

	if (unlikely(!idx_is_pending(dr, end)))

		return 0;



	vp = port->vp;

	vp = port->vp;

	dev = vp->dev;

	dev = vp->dev;

	netif_tx_lock(dev);

	if (unlikely(!idx_is_pending(dr, end))) {

		netif_tx_unlock(dev);

		return 0;

	}



	/* sync for race conditions with vnet_start_xmit() and tell xmit it

	/* sync for race conditions with vnet_start_xmit() and tell xmit it

	 * is time to send a trigger.

	 * is time to send a trigger.

	 */

	 */

	netif_tx_lock(dev);

	dr->cons = next_idx(end, dr);

	dr->cons = next_idx(end, dr);

	desc = vio_dring_entry(dr, dr->cons);

	desc = vio_dring_entry(dr, dr->cons);

	if (desc->hdr.state == VIO_DESC_READY && port->start_cons) {

	if (desc->hdr.state == VIO_DESC_READY && !port->start_cons) {

		/* vnet_start_xmit() just populated this dring but missed

		/* vnet_start_xmit() just populated this dring but missed

		 * sending the "start" LDC message to the consumer.

		 * sending the "start" LDC message to the consumer.

		 * Send a "start" trigger on its behalf.

		 * Send a "start" trigger on its behalf.
@@ -979,8 +981,10 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 




	rcu_read_lock();

	rcu_read_lock();

	port = __tx_port_find(vp, skb);

	port = __tx_port_find(vp, skb);

	if (unlikely(!port))

	if (unlikely(!port)) {

		rcu_read_unlock();

		goto out_dropped;

		goto out_dropped;

	}





	if (skb->len > port->rmtu) {

	if (skb->len > port->rmtu) {

		unsigned long localmtu = port->rmtu - ETH_HLEN;

		unsigned long localmtu = port->rmtu - ETH_HLEN;