From: Mike Galbraith <mgalbraith@suse.de>
Date: Wed Aug  2 10:55:41 CEST 2017
Subject: net: Move napi_hash_add/del() inside CONFIG_NET_RX_BUSY_POLL
Patch-mainline: Never, RT specific
References: SLE12 Realtime Extension

Since 545cd5e5ec54 ("net: Busy polling should ignore sender CPUs"),
kernel build fails when CONFIG_NET_RX_BUSY_POLL is disabled.  Move
napi_hash_add/del() accordingly.

Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
 include/linux/netdevice.h |   14 +++++++++++++-
 net/core/dev.c            |   17 ++++++++++++-----
 2 files changed, 25 insertions(+), 6 deletions(-)

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -492,6 +492,8 @@ static inline bool napi_complete(struct
 	return napi_complete_done(n, 0);
 }
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
+
 /**
  *	napi_hash_del - remove a NAPI from global table
  *	@napi: NAPI context
@@ -505,6 +507,17 @@ static inline bool napi_complete(struct
  * the needed RCU grace periods into a single one.
  */
 bool napi_hash_del(struct napi_struct *napi);
+struct net_device *dev_get_by_napi_id(unsigned int napi_id);
+
+#else /* !CONFIG_NET_RX_BUSY_POLL */
+
+static inline bool napi_hash_del(struct napi_struct *napi) { return false; }
+static inline struct net_device *dev_get_by_napi_id(unsigned int napi_id)
+{
+	return NULL;
+}
+
+#endif /* CONFIG_NET_RX_BUSY_POLL */
 
 /**
  *	napi_disable - prevent NAPI from scheduling
@@ -2683,7 +2696,6 @@ static inline void xmit_rec_dec(void)
 struct net_device *dev_get_by_index(struct net *net, int ifindex);
 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);
-struct net_device *dev_get_by_napi_id(unsigned int napi_id);
 int netdev_get_name(struct net *net, char *name, int ifindex);
 int dev_restart(struct net_device *dev);
 int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb);
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -163,7 +163,6 @@ static struct list_head offload_base __r
 static int netif_rx_internal(struct sk_buff *skb);
 static int call_netdevice_notifiers_info(unsigned long val,
 					 struct netdev_notifier_info *info);
-static struct napi_struct *napi_by_id(unsigned int napi_id);
 
 /*
  * The @dev_base_head list is protected by @dev_base_lock and the rtnl
@@ -187,11 +186,15 @@ static struct napi_struct *napi_by_id(un
 DEFINE_RWLOCK(dev_base_lock);
 EXPORT_SYMBOL(dev_base_lock);
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
+static struct napi_struct *napi_by_id(unsigned int napi_id);
+
 /* protects napi_hash addition/deletion and napi_gen_id */
 static DEFINE_SPINLOCK(napi_hash_lock);
 
 static unsigned int napi_gen_id = NR_CPUS;
 static DEFINE_READ_MOSTLY_HASHTABLE(napi_hash, 8);
+#endif
 
 static seqcount_t devnet_rename_seq;
 static DEFINE_MUTEX(devnet_rename_mutex);
@@ -868,6 +871,7 @@ struct net_device *dev_get_by_index(stru
 }
 EXPORT_SYMBOL(dev_get_by_index);
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
 /**
  *	dev_get_by_napi_id - find a device by napi_id
  *	@napi_id: ID of the NAPI struct
@@ -892,6 +896,7 @@ struct net_device *dev_get_by_napi_id(un
 	return napi ? napi->dev : NULL;
 }
 EXPORT_SYMBOL(dev_get_by_napi_id);
+#endif
 
 /**
  *	netdev_get_name - get a netdevice name, knowing its ifindex.
@@ -5984,6 +5989,8 @@ bool napi_complete_done(struct napi_stru
 }
 EXPORT_SYMBOL(napi_complete_done);
 
+#if defined(CONFIG_NET_RX_BUSY_POLL)
+
 /* must be called under rcu_read_lock(), as we dont take a reference */
 static struct napi_struct *napi_by_id(unsigned int napi_id)
 {
@@ -5997,8 +6004,6 @@ static struct napi_struct *napi_by_id(un
 	return NULL;
 }
 
-#if defined(CONFIG_NET_RX_BUSY_POLL)
-
 #define BUSY_POLL_BUDGET 8
 
 static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock)
@@ -6099,8 +6104,6 @@ out:
 }
 EXPORT_SYMBOL(napi_busy_loop);
 
-#endif /* CONFIG_NET_RX_BUSY_POLL */
-
 static void napi_hash_add(struct napi_struct *napi)
 {
 	if (test_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state) ||
@@ -6140,6 +6143,8 @@ bool napi_hash_del(struct napi_struct *n
 }
 EXPORT_SYMBOL_GPL(napi_hash_del);
 
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
 static enum hrtimer_restart napi_watchdog(struct hrtimer *timer)
 {
 	struct napi_struct *napi;
@@ -6187,7 +6192,9 @@ void netif_napi_add(struct net_device *d
 	set_bit(NAPI_STATE_SCHED, &napi->state);
 	set_bit(NAPI_STATE_NPSVC, &napi->state);
 	list_add_rcu(&napi->dev_list, &dev->napi_list);
+#ifdef CONFIG_NET_RX_BUSY_POLL
 	napi_hash_add(napi);
+#endif
 }
 EXPORT_SYMBOL(netif_napi_add);