net: un-inline sk_busy_loop()

There is really little gain from inlining this big function.
We'll soon make it even bigger in following patches.

This means we no longer need to export napi_by_id()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -460,15 +460,6 @@ static inline void napi_complete(struct napi_struct *n)
 	return napi_complete_done(n, 0);
 }
 
-/**
- *	napi_by_id - lookup a NAPI by napi_id
- *	@napi_id: hashed napi_id
- *
- * lookup @napi_id in napi_hash table
- * must be called under rcu_read_lock()
- */
-struct napi_struct *napi_by_id(unsigned int napi_id);
-
 /**
  *	napi_hash_add - add a NAPI to global hashtable
  *	@napi: napi context

include/net/busy_poll.h

@@ -72,50 +72,7 @@ static inline bool busy_loop_timeout(unsigned long end_time)
 	return time_after(now, end_time);
 }
 
-/* when used in sock_poll() nonblock is known at compile time to be true
- * so the loop and end_time will be optimized out
- */
-static inline bool sk_busy_loop(struct sock *sk, int nonblock)
-{
-	unsigned long end_time = !nonblock ? sk_busy_loop_end_time(sk) : 0;
-	const struct net_device_ops *ops;
-	struct napi_struct *napi;
-	int rc = false;
-
-	/*
-	 * rcu read lock for napi hash
-	 * bh so we don't race with net_rx_action
-	 */
-	rcu_read_lock_bh();
-
-	napi = napi_by_id(sk->sk_napi_id);
-	if (!napi)
-		goto out;
-
-	ops = napi->dev->netdev_ops;
-	if (!ops->ndo_busy_poll)
-		goto out;
-
-	do {
-		rc = ops->ndo_busy_poll(napi);
-
-		if (rc == LL_FLUSH_FAILED)
-			break; /* permanent failure */
-
-		if (rc > 0)
-			/* local bh are disabled so it is ok to use _BH */
-			NET_ADD_STATS_BH(sock_net(sk),
-					 LINUX_MIB_BUSYPOLLRXPACKETS, rc);
-		cpu_relax();
-
-	} while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) &&
-		 !need_resched() && !busy_loop_timeout(end_time));
-
-	rc = !skb_queue_empty(&sk->sk_receive_queue);
-out:
-	rcu_read_unlock_bh();
-	return rc;
-}
+bool sk_busy_loop(struct sock *sk, int nonblock);
 
 /* used in the NIC receive handler to mark the skb */
 static inline void skb_mark_napi_id(struct sk_buff *skb,

net/core/dev.c

@@ -96,6 +96,7 @@
 #include <linux/skbuff.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
+#include <net/busy_poll.h>
 #include <linux/rtnetlink.h>
 #include <linux/stat.h>
 #include <net/dst.h>
@@ -4663,7 +4664,7 @@ void napi_complete_done(struct napi_struct *n, int work_done)
 EXPORT_SYMBOL(napi_complete_done);
 
 /* must be called under rcu_read_lock(), as we dont take a reference */
-struct napi_struct *napi_by_id(unsigned int napi_id)
+static struct napi_struct *napi_by_id(unsigned int napi_id)
 {
 	unsigned int hash = napi_id % HASH_SIZE(napi_hash);
 	struct napi_struct *napi;
@@ -4674,7 +4675,52 @@ struct napi_struct *napi_by_id(unsigned int napi_id)
 
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(napi_by_id);
+
+#if defined(CONFIG_NET_RX_BUSY_POLL)
+bool sk_busy_loop(struct sock *sk, int nonblock)
+{
+	unsigned long end_time = !nonblock ? sk_busy_loop_end_time(sk) : 0;
+	const struct net_device_ops *ops;
+	struct napi_struct *napi;
+	int rc = false;
+
+	/*
+	 * rcu read lock for napi hash
+	 * bh so we don't race with net_rx_action
+	 */
+	rcu_read_lock_bh();
+
+	napi = napi_by_id(sk->sk_napi_id);
+	if (!napi)
+		goto out;
+
+	ops = napi->dev->netdev_ops;
+	if (!ops->ndo_busy_poll)
+		goto out;
+
+	do {
+		rc = ops->ndo_busy_poll(napi);
+
+		if (rc == LL_FLUSH_FAILED)
+			break; /* permanent failure */
+
+		if (rc > 0)
+			/* local bh are disabled so it is ok to use _BH */
+			NET_ADD_STATS_BH(sock_net(sk),
+					 LINUX_MIB_BUSYPOLLRXPACKETS, rc);
+		cpu_relax();
+
+	} while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) &&
+		 !need_resched() && !busy_loop_timeout(end_time));
+
+	rc = !skb_queue_empty(&sk->sk_receive_queue);
+out:
+	rcu_read_unlock_bh();
+	return rc;
+}
+EXPORT_SYMBOL(sk_busy_loop);
+
+#endif /* CONFIG_NET_RX_BUSY_POLL */
 
 void napi_hash_add(struct napi_struct *napi)
 {