net: remove sock_poll_busy_flag

Fold it into the only caller to make the code simpler and easier to read.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/busy_poll.h

@@ -121,12 +121,6 @@ static inline void sk_busy_loop(struct sock *sk, int nonblock)
 #endif
 }
 
-/* if this socket can poll_ll, tell the system call */
-static inline __poll_t sock_poll_busy_flag(struct socket *sock)
-{
-	return sk_can_busy_loop(sock->sk) ? POLL_BUSY_LOOP : 0;
-}
-
 /* used in the NIC receive handler to mark the skb */
 static inline void skb_mark_napi_id(struct sk_buff *skb,
 				    struct napi_struct *napi)

net/socket.c

@@ -1130,15 +1130,21 @@ EXPORT_SYMBOL(sock_create_lite);
 static __poll_t sock_poll(struct file *file, poll_table *wait)
 {
 	struct socket *sock = file->private_data;
-	__poll_t events = poll_requested_events(wait);
+	__poll_t events = poll_requested_events(wait), flag = 0;
 
 	if (!sock->ops->poll)
 		return 0;
 
+	if (sk_can_busy_loop(sock->sk)) {
 		/* poll once if requested by the syscall */
-	if (sk_can_busy_loop(sock->sk) && (events & POLL_BUSY_LOOP))
+		if (events & POLL_BUSY_LOOP)
 			sk_busy_loop(sock->sk, 1);
-	return sock->ops->poll(file, sock, wait) | sock_poll_busy_flag(sock);
+
+		/* if this socket can poll_ll, tell the system call */
+		flag = POLL_BUSY_LOOP;
+	}
+
+	return sock->ops->poll(file, sock, wait) | flag;
 }
 
 static int sock_mmap(struct file *file, struct vm_area_struct *vma)