Re: [RFC V3 PATCH 18/26] net/netpolicy: set tx queues according to policy

From: Kan Liang <redacted>

When the device tries to transmit a packet, netdev_pick_tx is called to
find the available tx queues. If the net policy is applied, it picks up
the assigned tx queue from net policy subsystem, and redirect the
traffic to the assigned queue.

Signed-off-by: Kan Liang <redacted>
---
 include/net/sock.h |  9 +++++++++
 net/core/dev.c     | 20 ++++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index e1e9e3d..ca97f35 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h

@@ -2280,4 +2280,13 @@ extern int sysctl_optmem_max;
 extern __u32 sysctl_wmem_default;
 extern __u32 sysctl_rmem_default;

+/* Return netpolicy instance information from socket. */
+static inline struct netpolicy_instance *netpolicy_find_instance(struct sock *sk)
+{
+#ifdef CONFIG_NETPOLICY
+       if (is_net_policy_valid(sk->sk_netpolicy.policy))
+               return &sk->sk_netpolicy;
+#endif
+       return NULL;
+}
 #endif /* _SOCK_H */

diff --git a/net/core/dev.c b/net/core/dev.c
index 34b5322..b9a8044 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -3266,6 +3266,7 @@ struct netdev_queue *netdev_pick_tx(struct net_device *dev,
                                    struct sk_buff *skb,
                                    void *accel_priv)
 {
+       struct sock *sk = skb->sk;
        int queue_index = 0;

 #ifdef CONFIG_XPS

@@ -3280,8 +3281,23 @@ struct netdev_queue *netdev_pick_tx(struct net_device *dev,
                if (ops->ndo_select_queue)
                        queue_index = ops->ndo_select_queue(dev, skb, accel_priv,
                                                            __netdev_pick_tx);
-               else
-                       queue_index = __netdev_pick_tx(dev, skb);
+               else {
+#ifdef CONFIG_NETPOLICY
+                       struct netpolicy_instance *instance;
+
+                       queue_index = -1;
+                       if (dev->netpolicy && sk) {
+                               instance = netpolicy_find_instance(sk);
+                               if (instance) {
+                                       if (!instance->dev)
+                                               instance->dev = dev;
+                                       queue_index = netpolicy_pick_queue(instance, false);
+                               }
+                       }
+                       if (queue_index < 0)
+#endif