1 files changed, 89 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 89825c1eccdc..cc1d6bba017a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2067,11 +2067,13 @@ int netdev_txq_to_tc(struct net_device *dev, unsigned int txq)
                 struct netdev_tc_txq *tc = &dev->tc_to_txq[0];
                 int i;
 
+                /* walk through the TCs and see if it falls into any of them */
                 for (i = 0; i < TC_MAX_QUEUE; i++, tc++) {
                         if ((txq - tc->offset) < tc->count)
                                 return i;
                 }
 
+                /* didn't find it, just return -1 to indicate no match */
                 return -1;
         }
 
@@ -2260,7 +2262,14 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
         unsigned int nr_ids;
 
         if (dev->num_tc) {
+                /* Do not allow XPS on subordinate device directly */
                 num_tc = dev->num_tc;
+                if (num_tc < 0)
+                        return -EINVAL;
+
+                /* If queue belongs to subordinate dev use its map */
+                dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
+
                 tc = netdev_txq_to_tc(dev, index);
                 if (tc < 0)
                         return -EINVAL;
@@ -2448,11 +2457,25 @@ int netif_set_xps_queue(struct net_device *dev, const struct cpumask *mask,
 EXPORT_SYMBOL(netif_set_xps_queue);
 
 #endif
+static void netdev_unbind_all_sb_channels(struct net_device *dev)
+{
+        struct netdev_queue *txq = &dev->_tx[dev->num_tx_queues];
+
+        /* Unbind any subordinate channels */
+        while (txq-- != &dev->_tx[0]) {
+                if (txq->sb_dev)
+                        netdev_unbind_sb_channel(dev, txq->sb_dev);
+        }
+}
+
 void netdev_reset_tc(struct net_device *dev)
 {
 #ifdef CONFIG_XPS
         netif_reset_xps_queues_gt(dev, 0);
 #endif
+        netdev_unbind_all_sb_channels(dev);
+
+        /* Reset TC configuration of device */
         dev->num_tc = 0;
         memset(dev->tc_to_txq, 0, sizeof(dev->tc_to_txq));
         memset(dev->prio_tc_map, 0, sizeof(dev->prio_tc_map));
@@ -2481,11 +2504,77 @@ int netdev_set_num_tc(struct net_device *dev, u8 num_tc)
 #ifdef CONFIG_XPS
         netif_reset_xps_queues_gt(dev, 0);
 #endif
+        netdev_unbind_all_sb_channels(dev);
+
         dev->num_tc = num_tc;
         return 0;
 }
 EXPORT_SYMBOL(netdev_set_num_tc);
 
+void netdev_unbind_sb_channel(struct net_device *dev,
+                              struct net_device *sb_dev)
+{
+        struct netdev_queue *txq = &dev->_tx[dev->num_tx_queues];
+
+#ifdef CONFIG_XPS
+        netif_reset_xps_queues_gt(sb_dev, 0);
+#endif
+        memset(sb_dev->tc_to_txq, 0, sizeof(sb_dev->tc_to_txq));
+        memset(sb_dev->prio_tc_map, 0, sizeof(sb_dev->prio_tc_map));
+
+        while (txq-- != &dev->_tx[0]) {
+                if (txq->sb_dev == sb_dev)
+                        txq->sb_dev = NULL;
+        }
+}
+EXPORT_SYMBOL(netdev_unbind_sb_channel);
+
+int netdev_bind_sb_channel_queue(struct net_device *dev,
+                                 struct net_device *sb_dev,
+                                 u8 tc, u16 count, u16 offset)
+{
+        /* Make certain the sb_dev and dev are already configured */
+        if (sb_dev->num_tc >= 0 || tc >= dev->num_tc)
+                return -EINVAL;
+
+        /* We cannot hand out queues we don't have */
+        if ((offset + count) > dev->real_num_tx_queues)
+                return -EINVAL;
+
+        /* Record the mapping */
+        sb_dev->tc_to_txq[tc].count = count;
+        sb_dev->tc_to_txq[tc].offset = offset;
+
+        /* Provide a way for Tx queue to find the tc_to_txq map or
+         * XPS map for itself.
+         */
+        while (count--)
+                netdev_get_tx_queue(dev, count + offset)->sb_dev = sb_dev;
+
+        return 0;
+}
+EXPORT_SYMBOL(netdev_bind_sb_channel_queue);
+
+int netdev_set_sb_channel(struct net_device *dev, u16 channel)
+{
+        /* Do not use a multiqueue device to represent a subordinate channel */
+        if (netif_is_multiqueue(dev))
+                return -ENODEV;
+
+        /* We allow channels 1 - 32767 to be used for subordinate channels.
+         * Channel 0 is meant to be "native" mode and used only to represent
+         * the main root device. We allow writing 0 to reset the device back
+         * to normal mode after being used as a subordinate channel.
+         */
+        if (channel > S16_MAX)
+                return -EINVAL;
+
+        dev->num_tc = -channel;
+
+        return 0;
+}
+EXPORT_SYMBOL(netdev_set_sb_channel);
+
 /*
  * Routine to help set real_num_tx_queues. To avoid skbs mapped to queues
  * greater than real_num_tx_queues stale skbs on the qdisc must be flushed.