[NETPOLL]: Introduce a netpoll_info struct

This patch introduces a netpoll_info structure, which the struct net_device
will now point to instead of pointing to a struct netpoll.  The reason for
this is two-fold: 1) fields such as the rx_flags, poll_owner, and poll_lock
should be maintained per net_device, not per netpoll;  and 2) this is a first
step in providing support for multiple netpoll clients to register against the
same net_device.

The struct netpoll is now pointed to by the netpoll_info structure.  As
such, the previous behaviour of the code is preserved.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 57 insertions, 29 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ba5d1236aa17..d6afd440cf7b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -41,7 +41,7 @@
 struct divert_blk;
 struct vlan_group;
 struct ethtool_ops;
-struct netpoll;
+struct netpoll_info;
                                         /* source back-compat hooks */
 #define SET_ETHTOOL_OPS(netdev,ops) \
         ( (netdev)->ethtool_ops = (ops) )
@@ -468,7 +468,7 @@ struct net_device
                                                      unsigned char *haddr);
         int                     (*neigh_setup)(struct net_device *dev, struct neigh_parms *);
 #ifdef CONFIG_NETPOLL
-        struct netpoll          *np;
+        struct netpoll_info     *npinfo;
 #endif
 #ifdef CONFIG_NET_POLL_CONTROLLER
         void                    (*poll_controller)(struct net_device *dev);
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 449a4fde6587..388cd91bc7a6 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -16,14 +16,18 @@ struct netpoll;
 struct netpoll {
         struct net_device *dev;
         char dev_name[16], *name;
-        int rx_flags;
         void (*rx_hook)(struct netpoll *, int, char *, int);
         void (*drop)(struct sk_buff *skb);
         u32 local_ip, remote_ip;
         u16 local_port, remote_port;
         unsigned char local_mac[6], remote_mac[6];
+};
+
+struct netpoll_info {
         spinlock_t poll_lock;
         int poll_owner;
+        int rx_flags;
+        struct netpoll *np;
 };
 
 void netpoll_poll(struct netpoll *np);
@@ -39,22 +43,27 @@ void netpoll_queue(struct sk_buff *skb);
 #ifdef CONFIG_NETPOLL
 static inline int netpoll_rx(struct sk_buff *skb)
 {
-        return skb->dev->np && skb->dev->np->rx_flags && __netpoll_rx(skb);
+        struct netpoll_info *npinfo = skb->dev->npinfo;
+
+        if (!npinfo || !npinfo->rx_flags)
+                return 0;
+
+        return npinfo->np && __netpoll_rx(skb);
 }
 
 static inline void netpoll_poll_lock(struct net_device *dev)
 {
-        if (dev->np) {
-                spin_lock(&dev->np->poll_lock);
-                dev->np->poll_owner = smp_processor_id();
+        if (dev->npinfo) {
+                spin_lock(&dev->npinfo->poll_lock);
+                dev->npinfo->poll_owner = smp_processor_id();
         }
 }
 
 static inline void netpoll_poll_unlock(struct net_device *dev)
 {
-        if (dev->np) {
-                dev->np->poll_owner = -1;
-                spin_unlock(&dev->np->poll_lock);
+        if (dev->npinfo) {
+                dev->npinfo->poll_owner = -1;
+                spin_unlock(&dev->npinfo->poll_lock);
         }
 }
 
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index a119696d5521..ab3c0c9713b0 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -130,19 +130,20 @@ static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  */
 static void poll_napi(struct netpoll *np)
 {
+        struct netpoll_info *npinfo = np->dev->npinfo;
         int budget = 16;
 
         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
-            np->poll_owner != smp_processor_id() &&
-            spin_trylock(&np->poll_lock)) {
-                np->rx_flags |= NETPOLL_RX_DROP;
+            npinfo->poll_owner != smp_processor_id() &&
+            spin_trylock(&npinfo->poll_lock)) {
+                npinfo->rx_flags |= NETPOLL_RX_DROP;
                 atomic_inc(&trapped);
 
                 np->dev->poll(np->dev, &budget);
 
                 atomic_dec(&trapped);
-                np->rx_flags &= ~NETPOLL_RX_DROP;
-                spin_unlock(&np->poll_lock);
+                npinfo->rx_flags &= ~NETPOLL_RX_DROP;
+                spin_unlock(&npinfo->poll_lock);
         }
 }
 
@@ -245,6 +246,7 @@ repeat:
 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 {
         int status;
+        struct netpoll_info *npinfo;
 
 repeat:
         if(!np || !np->dev || !netif_running(np->dev)) {
@@ -253,8 +255,9 @@ repeat:
         }
 
         /* avoid recursion */
-        if(np->poll_owner == smp_processor_id() ||
-           np->dev->xmit_lock_owner == smp_processor_id()) {
+        npinfo = np->dev->npinfo;
+        if (npinfo->poll_owner == smp_processor_id() ||
+            np->dev->xmit_lock_owner == smp_processor_id()) {
                 if (np->drop)
                         np->drop(skb);
                 else
@@ -341,14 +344,18 @@ void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 
 static void arp_reply(struct sk_buff *skb)
 {
+        struct netpoll_info *npinfo = skb->dev->npinfo;
         struct arphdr *arp;
         unsigned char *arp_ptr;
         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
         u32 sip, tip;
         struct sk_buff *send_skb;
-        struct netpoll *np = skb->dev->np;
+        struct netpoll *np = NULL;
 
-        if (!np) return;
+        if (npinfo)
+                np = npinfo->np;
+        if (!np)
+                return;
 
         /* No arp on this interface */
         if (skb->dev->flags & IFF_NOARP)
@@ -429,7 +436,7 @@ int __netpoll_rx(struct sk_buff *skb)
         int proto, len, ulen;
         struct iphdr *iph;
         struct udphdr *uh;
-        struct netpoll *np = skb->dev->np;
+        struct netpoll *np = skb->dev->npinfo->np;
 
         if (!np->rx_hook)
                 goto out;
@@ -611,9 +618,7 @@ int netpoll_setup(struct netpoll *np)
 {
         struct net_device *ndev = NULL;
         struct in_device *in_dev;
-
-        np->poll_lock = SPIN_LOCK_UNLOCKED;
-        np->poll_owner = -1;
+        struct netpoll_info *npinfo;
 
         if (np->dev_name)
                 ndev = dev_get_by_name(np->dev_name);
@@ -624,7 +629,16 @@ int netpoll_setup(struct netpoll *np)
         }
 
         np->dev = ndev;
-        ndev->np = np;
+        if (!ndev->npinfo) {
+                npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
+                if (!npinfo)
+                        goto release;
+
+                npinfo->np = NULL;
+                npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
+                npinfo->poll_owner = -1;
+        } else
+                npinfo = ndev->npinfo;
 
         if (!ndev->poll_controller) {
                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
@@ -693,12 +707,15 @@ int netpoll_setup(struct netpoll *np)
         }
 
         if(np->rx_hook)
-                np->rx_flags = NETPOLL_RX_ENABLED;
+                npinfo->rx_flags = NETPOLL_RX_ENABLED;
+        npinfo->np = np;
+        ndev->npinfo = npinfo;
 
         return 0;
 
  release:
-        ndev->np = NULL;
+        if (!ndev->npinfo)
+                kfree(npinfo);
         np->dev = NULL;
         dev_put(ndev);
         return -1;
@@ -706,9 +723,11 @@ int netpoll_setup(struct netpoll *np)
 
 void netpoll_cleanup(struct netpoll *np)
 {
-        if (np->dev)
-                np->dev->np = NULL;
-        dev_put(np->dev);
+        if (np->dev) {
+                if (np->dev->npinfo)
+                        np->dev->npinfo->np = NULL;
+                dev_put(np->dev);
+        }
         np->dev = NULL;
 }