1 files changed, 35 insertions, 3 deletions

diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index d813bfb1a847..23c89ab5a6ad 100644
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -32,6 +32,11 @@ MODULE_DESCRIPTION("Sun LDOM virtual network driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_MODULE_VERSION);
 
+/* Heuristic for the number of times to exponentially backoff and
+ * retry sending an LDC trigger when EAGAIN is encountered
+ */
+#define VNET_MAX_RETRIES        10
+
 /* Ordered from largest major to lowest */
 static struct vio_version vnet_versions[] = {
         { .major = 1, .minor = 0 },
@@ -260,6 +265,7 @@ static int vnet_send_ack(struct vnet_port *port, struct vio_dring_state *dr,
                 .state                  = vio_dring_state,
         };
         int err, delay;
+        int retries = 0;
 
         hdr.seq = dr->snd_nxt;
         delay = 1;
@@ -272,6 +278,13 @@ static int vnet_send_ack(struct vnet_port *port, struct vio_dring_state *dr,
                 udelay(delay);
                 if ((delay <<= 1) > 128)
                         delay = 128;
+                if (retries++ > VNET_MAX_RETRIES) {
+                        pr_info("ECONNRESET %x:%x:%x:%x:%x:%x\n",
+                                port->raddr[0], port->raddr[1],
+                                port->raddr[2], port->raddr[3],
+                                port->raddr[4], port->raddr[5]);
+                        err = -ECONNRESET;
+                }
         } while (err == -EAGAIN);
 
         return err;
@@ -475,8 +488,9 @@ static int handle_mcast(struct vnet_port *port, void *msgbuf)
         return 0;
 }
 
-static void maybe_tx_wakeup(struct vnet *vp)
+static void maybe_tx_wakeup(unsigned long param)
 {
+        struct vnet *vp = (struct vnet *)param;
         struct net_device *dev = vp->dev;
 
         netif_tx_lock(dev);
@@ -573,8 +587,13 @@ static void vnet_event(void *arg, int event)
                         break;
         }
         spin_unlock(&vio->lock);
+        /* Kick off a tasklet to wake the queue.  We cannot call
+         * maybe_tx_wakeup directly here because we could deadlock on
+         * netif_tx_lock() with dev_watchdog()
+         */
         if (unlikely(tx_wakeup && err != -ECONNRESET))
-                maybe_tx_wakeup(port->vp);
+                tasklet_schedule(&port->vp->vnet_tx_wakeup);
+
         local_irq_restore(flags);
 }
 
@@ -593,6 +612,7 @@ static int __vnet_tx_trigger(struct vnet_port *port)
                 .end_idx                = (u32) -1,
         };
         int err, delay;
+        int retries = 0;
 
         hdr.seq = dr->snd_nxt;
         delay = 1;
@@ -605,6 +625,8 @@ static int __vnet_tx_trigger(struct vnet_port *port)
                 udelay(delay);
                 if ((delay <<= 1) > 128)
                         delay = 128;
+                if (retries++ > VNET_MAX_RETRIES)
+                        break;
         } while (err == -EAGAIN);
 
         return err;
@@ -691,7 +713,15 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 memset(tx_buf+VNET_PACKET_SKIP+skb->len, 0, len - skb->len);
         }
 
-        d->hdr.ack = VIO_ACK_ENABLE;
+        /* We don't rely on the ACKs to free the skb in vnet_start_xmit(),
+         * thus it is safe to not set VIO_ACK_ENABLE for each transmission:
+         * the protocol itself does not require it as long as the peer
+         * sends a VIO_SUBTYPE_ACK for VIO_DRING_STOPPED.
+         *
+         * An ACK for every packet in the ring is expensive as the
+         * sending of LDC messages is slow and affects performance.
+         */
+        d->hdr.ack = VIO_ACK_DISABLE;
         d->size = len;
         d->ncookies = port->tx_bufs[dr->prod].ncookies;
         for (i = 0; i < d->ncookies; i++)
@@ -1046,6 +1076,7 @@ static struct vnet *vnet_new(const u64 *local_mac)
         vp = netdev_priv(dev);
 
         spin_lock_init(&vp->lock);
+        tasklet_init(&vp->vnet_tx_wakeup, maybe_tx_wakeup, (unsigned long)vp);
         vp->dev = dev;
 
         INIT_LIST_HEAD(&vp->port_list);
@@ -1105,6 +1136,7 @@ static void vnet_cleanup(void)
                 vp = list_first_entry(&vnet_list, struct vnet, list);
                 list_del(&vp->list);
                 dev = vp->dev;
+                tasklet_kill(&vp->vnet_tx_wakeup);
                 /* vio_unregister_driver() should have cleaned up port_list */
                 BUG_ON(!list_empty(&vp->port_list));
                 unregister_netdev(dev);