bridge: make bridge support netpoll

Based on the previous patch, make bridge support netpoll by:

1) implement the 2 methods to support netpoll for bridge;

2) modify netpoll during forwarding packets via bridge;

3) disable netpoll support of bridge when a netpoll-unabled device
   is added to bridge;

4) enable netpoll support when all underlying devices support netpoll.

Cc: David Miller <davem@davemloft.net>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 108 insertions, 1 deletions

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 82599405dc15..074c59690fc5 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -13,8 +13,10 @@
 
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/netpoll.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
+#include <linux/list.h>
 
 #include <asm/uaccess.h>
 #include "br_private.h"
@@ -188,6 +190,59 @@ static int br_set_tx_csum(struct net_device *dev, u32 data)
         return 0;
 }
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+bool br_devices_support_netpoll(struct net_bridge *br)
+{
+        struct net_bridge_port *p;
+        bool ret = true;
+        int count = 0;
+        unsigned long flags;
+
+        spin_lock_irqsave(&br->lock, flags);
+        list_for_each_entry(p, &br->port_list, list) {
+                count++;
+                if ((p->dev->priv_flags & IFF_DISABLE_NETPOLL) ||
+                    !p->dev->netdev_ops->ndo_poll_controller)
+                        ret = false;
+        }
+        spin_unlock_irqrestore(&br->lock, flags);
+        return count != 0 && ret;
+}
+
+static void br_poll_controller(struct net_device *br_dev)
+{
+        struct netpoll *np = br_dev->npinfo->netpoll;
+
+        if (np->real_dev != br_dev)
+                netpoll_poll_dev(np->real_dev);
+}
+
+void br_netpoll_cleanup(struct net_device *br_dev)
+{
+        struct net_bridge *br = netdev_priv(br_dev);
+        struct net_bridge_port *p, *n;
+        const struct net_device_ops *ops;
+
+        br->dev->npinfo = NULL;
+        list_for_each_entry_safe(p, n, &br->port_list, list) {
+                if (p->dev) {
+                        ops = p->dev->netdev_ops;
+                        if (ops->ndo_netpoll_cleanup)
+                                ops->ndo_netpoll_cleanup(p->dev);
+                        else
+                                p->dev->npinfo = NULL;
+                }
+        }
+}
+
+#else
+
+void br_netpoll_cleanup(struct net_device *br_dev)
+{
+}
+
+#endif
+
 static const struct ethtool_ops br_ethtool_ops = {
         .get_drvinfo    = br_getinfo,
         .get_link       = ethtool_op_get_link,
@@ -211,6 +266,10 @@ static const struct net_device_ops br_netdev_ops = {
         .ndo_set_multicast_list  = br_dev_set_multicast_list,
         .ndo_change_mtu          = br_change_mtu,
         .ndo_do_ioctl            = br_dev_ioctl,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        .ndo_netpoll_cleanup     = br_netpoll_cleanup,
+        .ndo_poll_controller     = br_poll_controller,
+#endif
 };
 
 static void br_dev_free(struct net_device *dev)
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 396f077216a3..92ad9feb199d 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/netpoll.h>
 #include <linux/skbuff.h>
 #include <linux/if_vlan.h>
 #include <linux/netfilter_bridge.h>
@@ -50,7 +51,13 @@ int br_dev_queue_push_xmit(struct sk_buff *skb)
                 else {
                         skb_push(skb, ETH_HLEN);
 
-                        dev_queue_xmit(skb);
+#ifdef CONFIG_NET_POLL_CONTROLLER
+                        if (unlikely(skb->dev->priv_flags & IFF_IN_NETPOLL)) {
+                                netpoll_send_skb(skb->dev->npinfo->netpoll, skb);
+                                skb->dev->priv_flags &= ~IFF_IN_NETPOLL;
+                        } else
+#endif
+                                dev_queue_xmit(skb);
                 }
         }
 
@@ -66,9 +73,23 @@ int br_forward_finish(struct sk_buff *skb)
 
 static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
 {
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        struct net_bridge *br = to->br;
+        if (unlikely(br->dev->priv_flags & IFF_IN_NETPOLL)) {
+                struct netpoll *np;
+                to->dev->npinfo = skb->dev->npinfo;
+                np = skb->dev->npinfo->netpoll;
+                np->real_dev = np->dev = to->dev;
+                to->dev->priv_flags |= IFF_IN_NETPOLL;
+        }
+#endif
         skb->dev = to->dev;
         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
                         br_forward_finish);
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        if (skb->dev->npinfo)
+                skb->dev->npinfo->netpoll->dev = br->dev;
+#endif
 }
 
 static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 521439333316..537bdd60d9b9 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -13,6 +13,7 @@
 
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/netpoll.h>
 #include <linux/ethtool.h>
 #include <linux/if_arp.h>
 #include <linux/module.h>
@@ -153,6 +154,14 @@ static void del_nbp(struct net_bridge_port *p)
         kobject_uevent(&p->kobj, KOBJ_REMOVE);
         kobject_del(&p->kobj);
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        if (br_devices_support_netpoll(br))
+                br->dev->priv_flags &= ~IFF_DISABLE_NETPOLL;
+        if (dev->netdev_ops->ndo_netpoll_cleanup)
+                dev->netdev_ops->ndo_netpoll_cleanup(dev);
+        else
+                dev->npinfo = NULL;
+#endif
         call_rcu(&p->rcu, destroy_nbp_rcu);
 }
 
@@ -165,6 +174,8 @@ static void del_br(struct net_bridge *br, struct list_head *head)
                 del_nbp(p);
         }
 
+        br_netpoll_cleanup(br->dev);
+
         del_timer_sync(&br->gc_timer);
 
         br_sysfs_delbr(br->dev);
@@ -444,6 +455,20 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 
         kobject_uevent(&p->kobj, KOBJ_ADD);
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        if (br_devices_support_netpoll(br)) {
+                br->dev->priv_flags &= ~IFF_DISABLE_NETPOLL;
+                if (br->dev->npinfo)
+                        dev->npinfo = br->dev->npinfo;
+        } else if (!(br->dev->priv_flags & IFF_DISABLE_NETPOLL)) {
+                br->dev->priv_flags |= IFF_DISABLE_NETPOLL;
+                printk(KERN_INFO "New device %s does not support netpoll\n",
+                        dev->name);
+                printk(KERN_INFO "Disabling netpoll for %s\n",
+                        br->dev->name);
+        }
+#endif
+
         return 0;
 err2:
         br_fdb_delete_by_port(br, p, 1);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 018499ebe19d..3d2d3fe0a97e 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -253,6 +253,8 @@ static inline int br_is_root_bridge(const struct net_bridge *br)
 extern void br_dev_setup(struct net_device *dev);
 extern netdev_tx_t br_dev_xmit(struct sk_buff *skb,
                                struct net_device *dev);
+extern bool br_devices_support_netpoll(struct net_bridge *br);
+extern void br_netpoll_cleanup(struct net_device *br_dev);
 
 /* br_fdb.c */
 extern int br_fdb_init(void);