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Commit 13b13dd9 authored by Sowmini Varadhan's avatar Sowmini Varadhan Committed by David S. Miller
Browse files

sunvnet: Remove irqsave/irqrestore on vio.lock 



After the  NAPIfication of sunvnet, we no longer need to
synchronize by doing irqsave/restore on vio.lock in the
I/O fastpath.

NAPI ->poll() is non-reentrant, so all RX processing occurs
strictly in a serialized environment. TX reclaim is done in NAPI
context, so the netif_tx_lock can be used to serialize
critical sections between Tx and Rx paths.

Signed-off-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2a968dd8

drivers/net/ethernet/sun/sunvnet.c

+5 −25
Original line number Original line Diff line number Diff line
@@ -842,18 +842,6 @@ struct vnet_port *__tx_port_find(struct vnet *vp, struct sk_buff *skb) 
	return NULL;

	return NULL;

}

}





struct vnet_port *tx_port_find(struct vnet *vp, struct sk_buff *skb)

{

	struct vnet_port *ret;

	unsigned long flags;



	spin_lock_irqsave(&vp->lock, flags);

	ret = __tx_port_find(vp, skb);

	spin_unlock_irqrestore(&vp->lock, flags);



	return ret;

}



static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port,

static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port,

					  unsigned *pending)

					  unsigned *pending)

{

{
@@ -914,11 +902,10 @@ static void vnet_clean_timer_expire(unsigned long port0) 
	struct vnet_port *port = (struct vnet_port *)port0;

	struct vnet_port *port = (struct vnet_port *)port0;

	struct sk_buff *freeskbs;

	struct sk_buff *freeskbs;

	unsigned pending;

	unsigned pending;

	unsigned long flags;





	spin_lock_irqsave(&port->vio.lock, flags);

	netif_tx_lock(port->vp->dev);

	freeskbs = vnet_clean_tx_ring(port, &pending);

	freeskbs = vnet_clean_tx_ring(port, &pending);

	spin_unlock_irqrestore(&port->vio.lock, flags);

	netif_tx_unlock(port->vp->dev);





	vnet_free_skbs(freeskbs);

	vnet_free_skbs(freeskbs);
@@ -971,7 +958,6 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct vnet_port *port = NULL;

	struct vnet_port *port = NULL;

	struct vio_dring_state *dr;

	struct vio_dring_state *dr;

	struct vio_net_desc *d;

	struct vio_net_desc *d;

	unsigned long flags;

	unsigned int len;

	unsigned int len;

	struct sk_buff *freeskbs = NULL;

	struct sk_buff *freeskbs = NULL;

	int i, err, txi;

	int i, err, txi;
@@ -984,7 +970,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		goto out_dropped;

		goto out_dropped;





	rcu_read_lock();

	rcu_read_lock();

	port = tx_port_find(vp, skb);

	port = __tx_port_find(vp, skb);

	if (unlikely(!port))

	if (unlikely(!port))

		goto out_dropped;

		goto out_dropped;
@@ -1020,8 +1006,6 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		goto out_dropped;

		goto out_dropped;

	}

	}





	spin_lock_irqsave(&port->vio.lock, flags);



	dr = &port->vio.drings[VIO_DRIVER_TX_RING];

	dr = &port->vio.drings[VIO_DRIVER_TX_RING];

	if (unlikely(vnet_tx_dring_avail(dr) < 1)) {

	if (unlikely(vnet_tx_dring_avail(dr) < 1)) {

		if (!netif_queue_stopped(dev)) {

		if (!netif_queue_stopped(dev)) {
@@ -1055,7 +1039,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
			     (LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_RW));

			     (LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_RW));

	if (err < 0) {

	if (err < 0) {

		netdev_info(dev, "tx buffer map error %d\n", err);

		netdev_info(dev, "tx buffer map error %d\n", err);

		goto out_dropped_unlock;

		goto out_dropped;

	}

	}

	port->tx_bufs[txi].ncookies = err;

	port->tx_bufs[txi].ncookies = err;
@@ -1108,7 +1092,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		netdev_info(dev, "TX trigger error %d\n", err);

		netdev_info(dev, "TX trigger error %d\n", err);

		d->hdr.state = VIO_DESC_FREE;

		d->hdr.state = VIO_DESC_FREE;

		dev->stats.tx_carrier_errors++;

		dev->stats.tx_carrier_errors++;

		goto out_dropped_unlock;

		goto out_dropped;

	}

	}





ldc_start_done:

ldc_start_done:
@@ -1124,7 +1108,6 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
			netif_wake_queue(dev);

			netif_wake_queue(dev);

	}

	}





	spin_unlock_irqrestore(&port->vio.lock, flags);

	(void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);

	(void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);

	rcu_read_unlock();

	rcu_read_unlock();
@@ -1132,9 +1115,6 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) 




	return NETDEV_TX_OK;

	return NETDEV_TX_OK;





out_dropped_unlock:

	spin_unlock_irqrestore(&port->vio.lock, flags);



out_dropped:

out_dropped:

	if (pending)

	if (pending)

		(void)mod_timer(&port->clean_timer,

		(void)mod_timer(&port->clean_timer,