sunvnet: Use one Tx queue per vnet_port

Use multple Tx netdev queues for sunvnet by supporting a one-to-one
mapping between vnet_port and Tx queue. Provide a ndo_select_queue
indirection (vnet_select_queue()) which selects the queue based
on the peer that would be selected in vnet_start_xmit()

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 65 insertions, 31 deletions

diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index 7ada479f9604..e7bb63b2d525 100644
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -40,6 +40,8 @@ MODULE_DESCRIPTION("Sun LDOM virtual network driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_MODULE_VERSION);
 
+#define VNET_MAX_TXQS           16
+
 /* Heuristic for the number of times to exponentially backoff and
  * retry sending an LDC trigger when EAGAIN is encountered
  */
@@ -551,6 +553,8 @@ static int vnet_ack(struct vnet_port *port, void *msgbuf)
         struct vnet *vp;
         u32 end;
         struct vio_net_desc *desc;
+        struct netdev_queue *txq;
+
         if (unlikely(pkt->tag.stype_env != VIO_DRING_DATA))
                 return 0;
 
@@ -580,7 +584,8 @@ static int vnet_ack(struct vnet_port *port, void *msgbuf)
         }
         netif_tx_unlock(dev);
 
-        if (unlikely(netif_queue_stopped(dev) &&
+        txq = netdev_get_tx_queue(dev, port->q_index);
+        if (unlikely(netif_tx_queue_stopped(txq) &&
                      vnet_tx_dring_avail(dr) >= VNET_TX_WAKEUP_THRESH(dr)))
                 return 1;
 
@@ -608,31 +613,23 @@ static int handle_mcast(struct vnet_port *port, void *msgbuf)
         return 0;
 }
 
-static void maybe_tx_wakeup(struct vnet *vp)
+/* Got back a STOPPED LDC message on port. If the queue is stopped,
+ * wake it up so that we'll send out another START message at the
+ * next TX.
+ */
+static void maybe_tx_wakeup(struct vnet_port *port)
 {
-        struct net_device *dev = vp->dev;
+        struct netdev_queue *txq;
 
-        netif_tx_lock(dev);
-        if (likely(netif_queue_stopped(dev))) {
-                struct vnet_port *port;
-                int wake = 1;
-
-                rcu_read_lock();
-                list_for_each_entry_rcu(port, &vp->port_list, list) {
-                        struct vio_dring_state *dr;
-
-                        dr = &port->vio.drings[VIO_DRIVER_TX_RING];
-                        if (vnet_tx_dring_avail(dr) <
-                            VNET_TX_WAKEUP_THRESH(dr)) {
-                                wake = 0;
-                                break;
-                        }
-                }
-                rcu_read_unlock();
-                if (wake)
-                        netif_wake_queue(dev);
+        txq = netdev_get_tx_queue(port->vp->dev, port->q_index);
+        __netif_tx_lock(txq, smp_processor_id());
+        if (likely(netif_tx_queue_stopped(txq))) {
+                struct vio_dring_state *dr;
+
+                dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+                        netif_tx_wake_queue(txq);
         }
-        netif_tx_unlock(dev);
+        __netif_tx_unlock(txq);
 }
 
 static inline bool port_is_up(struct vnet_port *vnet)
@@ -748,7 +745,7 @@ napi_resume:
                         break;
         }
         if (unlikely(tx_wakeup && err != -ECONNRESET))
-                maybe_tx_wakeup(port->vp);
+                maybe_tx_wakeup(port);
         return npkts;
 }
 
@@ -953,6 +950,16 @@ static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, void **pstart,
         return skb;
 }
 
+static u16
+vnet_select_queue(struct net_device *dev, struct sk_buff *skb,
+                  void *accel_priv, select_queue_fallback_t fallback)
+{
+        struct vnet *vp = netdev_priv(dev);
+        struct vnet_port *port = __tx_port_find(vp, skb);
+
+        return port->q_index;
+}
+
 static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct vnet *vp = netdev_priv(dev);
@@ -965,6 +972,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
         void *start = NULL;
         int nlen = 0;
         unsigned pending = 0;
+        struct netdev_queue *txq;
 
         skb = vnet_skb_shape(skb, &start, &nlen);
         if (unlikely(!skb))
@@ -1008,9 +1016,11 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
         }
 
         dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+        i = skb_get_queue_mapping(skb);
+        txq = netdev_get_tx_queue(dev, i);
         if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
-                if (!netif_queue_stopped(dev)) {
-                        netif_stop_queue(dev);
+                if (!netif_tx_queue_stopped(txq)) {
+                        netif_tx_stop_queue(txq);
 
                         /* This is a hard error, log it. */
                         netdev_err(dev, "BUG! Tx Ring full when queue awake!\n");
@@ -1104,9 +1114,9 @@ ldc_start_done:
 
         dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
         if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
-                netif_stop_queue(dev);
+                netif_tx_stop_queue(txq);
                 if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
-                        netif_wake_queue(dev);
+                        netif_tx_wake_queue(txq);
         }
 
         (void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);
@@ -1139,14 +1149,14 @@ static void vnet_tx_timeout(struct net_device *dev)
 static int vnet_open(struct net_device *dev)
 {
         netif_carrier_on(dev);
-        netif_start_queue(dev);
+        netif_tx_start_all_queues(dev);
 
         return 0;
 }
 
 static int vnet_close(struct net_device *dev)
 {
-        netif_stop_queue(dev);
+        netif_tx_stop_all_queues(dev);
         netif_carrier_off(dev);
 
         return 0;
@@ -1420,6 +1430,7 @@ static const struct net_device_ops vnet_ops = {
         .ndo_tx_timeout         = vnet_tx_timeout,
         .ndo_change_mtu         = vnet_change_mtu,
         .ndo_start_xmit         = vnet_start_xmit,
+        .ndo_select_queue       = vnet_select_queue,
 #ifdef CONFIG_NET_POLL_CONTROLLER
         .ndo_poll_controller    = vnet_poll_controller,
 #endif
@@ -1431,7 +1442,7 @@ static struct vnet *vnet_new(const u64 *local_mac)
         struct vnet *vp;
         int err, i;
 
-        dev = alloc_etherdev(sizeof(*vp));
+        dev = alloc_etherdev_mqs(sizeof(*vp), VNET_MAX_TXQS, 1);
         if (!dev)
                 return ERR_PTR(-ENOMEM);
         dev->needed_headroom = VNET_PACKET_SKIP + 8;
@@ -1556,6 +1567,25 @@ static void print_version(void)
 
 const char *remote_macaddr_prop = "remote-mac-address";
 
+static void
+vnet_port_add_txq(struct vnet_port *port)
+{
+        struct vnet *vp = port->vp;
+        int n;
+
+        n = vp->nports++;
+        n = n & (VNET_MAX_TXQS - 1);
+        port->q_index = n;
+        netif_tx_wake_queue(netdev_get_tx_queue(vp->dev, port->q_index));
+}
+
+static void
+vnet_port_rm_txq(struct vnet_port *port)
+{
+        port->vp->nports--;
+        netif_tx_stop_queue(netdev_get_tx_queue(port->vp->dev, port->q_index));
+}
+
 static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 {
         struct mdesc_handle *hp;
@@ -1624,6 +1654,7 @@ static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
                 list_add_tail_rcu(&port->list, &vp->port_list);
         hlist_add_head_rcu(&port->hash,
                            &vp->port_hash[vnet_hashfn(port->raddr)]);
+        vnet_port_add_txq(port);
         spin_unlock_irqrestore(&vp->lock, flags);
 
         dev_set_drvdata(&vdev->dev, port);
@@ -1668,6 +1699,7 @@ static int vnet_port_remove(struct vio_dev *vdev)
 
                 synchronize_rcu();
                 del_timer_sync(&port->clean_timer);
+                vnet_port_rm_txq(port);
                 netif_napi_del(&port->napi);
                 vnet_port_free_tx_bufs(port);
                 vio_ldc_free(&port->vio);
diff --git a/drivers/net/ethernet/sun/sunvnet.h b/drivers/net/ethernet/sun/sunvnet.h
index c8a862e471dd..cd5d343ea232 100644
--- a/drivers/net/ethernet/sun/sunvnet.h
+++ b/drivers/net/ethernet/sun/sunvnet.h
@@ -61,6 +61,7 @@ struct vnet_port {
         u32                     napi_stop_idx;
         bool                    napi_resume;
         int                     rx_event;
+        u16                     q_index;
 };
 
 static inline struct vnet_port *to_vnet_port(struct vio_driver_state *vio)
@@ -102,6 +103,7 @@ struct vnet {
         struct list_head        list;
         u64                     local_mac;
 
+        int                     nports;
 };
 
 #endif /* _SUNVNET_H */