Merge branch 'netpoll-next'

Eric W. Biederman says:

====================
netpoll: Cleanup received packet processing

This is the long-winded, careful, and polite version of removing the netpoll
receive packet processing.

First I untangle the code in small steps.  Then I modify the code to not
force reception and dropping of packets when we are transmiting a packet
with netpoll.  Finally I move all of the packet reception under
CONFIG_NETPOLL_TRAP and delete CONFIG_NETPOLL_TRAP.

If someone wants to do a stable backport of these patches, it would
require backporting the first 18 patches that handle the budget == 0 in
the networking drivers, and the first 6 of these patches.

If anyone wants to resurrect netpoll packet reception someday it should
just be a matter of reverting the last patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -177,11 +177,6 @@ config NETCONSOLE_DYNAMIC
 config NETPOLL
 	def_bool NETCONSOLE
 
-config NETPOLL_TRAP
-	bool "Netpoll traffic trapping"
-	default n
-	depends on NETPOLL
-
 config NET_POLL_CONTROLLER
 	def_bool NETPOLL
 

include/linux/netdevice.h

@@ -1979,9 +1979,6 @@ struct net_device *__dev_get_by_index(struct net *net, int ifindex);
 struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);
 int netdev_get_name(struct net *net, char *name, int ifindex);
 int dev_restart(struct net_device *dev);
-#ifdef CONFIG_NETPOLL_TRAP
-int netpoll_trap(void);
-#endif
 int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb);
 
 static inline unsigned int skb_gro_offset(const struct sk_buff *skb)
@@ -2186,12 +2183,6 @@ static inline void netif_tx_start_all_queues(struct net_device *dev)
 
 static inline void netif_tx_wake_queue(struct netdev_queue *dev_queue)
 {
-#ifdef CONFIG_NETPOLL_TRAP
-	if (netpoll_trap()) {
-		netif_tx_start_queue(dev_queue);
-		return;
-	}
-#endif
 	if (test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &dev_queue->state))
 		__netif_schedule(dev_queue->qdisc);
 }
@@ -2435,10 +2426,6 @@ static inline void netif_start_subqueue(struct net_device *dev, u16 queue_index)
 static inline void netif_stop_subqueue(struct net_device *dev, u16 queue_index)
 {
 	struct netdev_queue *txq = netdev_get_tx_queue(dev, queue_index);
-#ifdef CONFIG_NETPOLL_TRAP
-	if (netpoll_trap())
-		return;
-#endif
 	netif_tx_stop_queue(txq);
 }
 
@@ -2473,10 +2460,6 @@ static inline bool netif_subqueue_stopped(const struct net_device *dev,
 static inline void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
 {
 	struct netdev_queue *txq = netdev_get_tx_queue(dev, queue_index);
-#ifdef CONFIG_NETPOLL_TRAP
-	if (netpoll_trap())
-		return;
-#endif
 	if (test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &txq->state))
 		__netif_schedule(txq->qdisc);
 }

include/linux/netpoll.h

@@ -24,27 +24,20 @@ struct netpoll {
 	struct net_device *dev;
 	char dev_name[IFNAMSIZ];
 	const char *name;
-	void (*rx_skb_hook)(struct netpoll *np, int source, struct sk_buff *skb,
-			    int offset, int len);
 
 	union inet_addr local_ip, remote_ip;
 	bool ipv6;
 	u16 local_port, remote_port;
 	u8 remote_mac[ETH_ALEN];
 
-	struct list_head rx; /* rx_np list element */
 	struct work_struct cleanup_work;
 };
 
 struct netpoll_info {
 	atomic_t refcnt;
 
-	unsigned long rx_flags;
-	spinlock_t rx_lock;
 	struct semaphore dev_lock;
-	struct list_head rx_np; /* netpolls that registered an rx_skb_hook */
 
-	struct sk_buff_head neigh_tx; /* list of neigh requests to reply to */
 	struct sk_buff_head txq;
 
 	struct delayed_work tx_work;
@@ -66,12 +59,9 @@ void netpoll_print_options(struct netpoll *np);
 int netpoll_parse_options(struct netpoll *np, char *opt);
 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp);
 int netpoll_setup(struct netpoll *np);
-int netpoll_trap(void);
-void netpoll_set_trap(int trap);
 void __netpoll_cleanup(struct netpoll *np);
 void __netpoll_free_async(struct netpoll *np);
 void netpoll_cleanup(struct netpoll *np);
-int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo);
 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 			     struct net_device *dev);
 static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
@@ -82,46 +72,7 @@ static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 	local_irq_restore(flags);
 }
 
-
-
 #ifdef CONFIG_NETPOLL
-static inline bool netpoll_rx_on(struct sk_buff *skb)
-{
-	struct netpoll_info *npinfo = rcu_dereference_bh(skb->dev->npinfo);
-
-	return npinfo && (!list_empty(&npinfo->rx_np) || npinfo->rx_flags);
-}
-
-static inline bool netpoll_rx(struct sk_buff *skb)
-{
-	struct netpoll_info *npinfo;
-	unsigned long flags;
-	bool ret = false;
-
-	local_irq_save(flags);
-
-	if (!netpoll_rx_on(skb))
-		goto out;
-
-	npinfo = rcu_dereference_bh(skb->dev->npinfo);
-	spin_lock(&npinfo->rx_lock);
-	/* check rx_flags again with the lock held */
-	if (npinfo->rx_flags && __netpoll_rx(skb, npinfo))
-		ret = true;
-	spin_unlock(&npinfo->rx_lock);
-
-out:
-	local_irq_restore(flags);
-	return ret;
-}
-
-static inline int netpoll_receive_skb(struct sk_buff *skb)
-{
-	if (!list_empty(&skb->dev->napi_list))
-		return netpoll_rx(skb);
-	return 0;
-}
-
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
 {
 	struct net_device *dev = napi->dev;
@@ -150,18 +101,6 @@ static inline bool netpoll_tx_running(struct net_device *dev)
 }
 
 #else
-static inline bool netpoll_rx(struct sk_buff *skb)
-{
-	return false;
-}
-static inline bool netpoll_rx_on(struct sk_buff *skb)
-{
-	return false;
-}
-static inline int netpoll_receive_skb(struct sk_buff *skb)
-{
-	return 0;
-}
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
 {
 	return NULL;

net/core/dev.c

@@ -3231,10 +3231,6 @@ static int netif_rx_internal(struct sk_buff *skb)
 {
 	int ret;
 
-	/* if netpoll wants it, pretend we never saw it */
-	if (netpoll_rx(skb))
-		return NET_RX_DROP;
-
 	net_timestamp_check(netdev_tstamp_prequeue, skb);
 
 	trace_netif_rx(skb);
@@ -3520,10 +3516,6 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc)
 
 	trace_netif_receive_skb(skb);
 
-	/* if we've gotten here through NAPI, check netpoll */
-	if (netpoll_receive_skb(skb))
-		goto out;
-
 	orig_dev = skb->dev;
 
 	skb_reset_network_header(skb);
@@ -3650,7 +3642,6 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc)
 
 unlock:
 	rcu_read_unlock();
-out:
 	return ret;
 }
 
@@ -3875,7 +3866,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 	int same_flow;
 	enum gro_result ret;
 
-	if (!(skb->dev->features & NETIF_F_GRO) || netpoll_rx_on(skb))
+	if (!(skb->dev->features & NETIF_F_GRO))
 		goto normal;
 
 	if (skb_is_gso(skb) || skb_has_frag_list(skb))