[NET]: Move sysctl_max_syn_backlog into request_sock.c

This fixes the CONFIG_INET=n build failure noticed
by Andrew Morton.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -564,7 +564,6 @@ static __inline__ int tcp_sk_listen_hashfn(struct sock *sk)
 #define TCP_NAGLE_PUSH		4	/* Cork is overriden for already queued data */
 
 /* sysctl variables for tcp */
-extern int sysctl_max_syn_backlog;
 extern int sysctl_tcp_timestamps;
 extern int sysctl_tcp_window_scaling;
 extern int sysctl_tcp_sack;

net/core/request_sock.c

@@ -18,6 +18,22 @@
 
 #include <net/request_sock.h>
 
+/*
+ * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
+ * One SYN_RECV socket costs about 80bytes on a 32bit machine.
+ * It would be better to replace it with a global counter for all sockets
+ * but then some measure against one socket starving all other sockets
+ * would be needed.
+ *
+ * It was 128 by default. Experiments with real servers show, that
+ * it is absolutely not enough even at 100conn/sec. 256 cures most
+ * of problems. This value is adjusted to 128 for very small machines
+ * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
+ * Further increasing requires to change hash table size.
+ */
+int sysctl_max_syn_backlog = 256;
+EXPORT_SYMBOL(sysctl_max_syn_backlog);
+
 int reqsk_queue_alloc(struct request_sock_queue *queue,
 		      const int nr_table_entries)
 {

net/ipv4/tcp_ipv4.c

@@ -1366,21 +1366,6 @@ static inline struct ip_options *tcp_v4_save_options(struct sock *sk,
 	return dopt;
 }
 
-/*
- * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
- * One SYN_RECV socket costs about 80bytes on a 32bit machine.
- * It would be better to replace it with a global counter for all sockets
- * but then some measure against one socket starving all other sockets
- * would be needed.
- *
- * It was 128 by default. Experiments with real servers show, that
- * it is absolutely not enough even at 100conn/sec. 256 cures most
- * of problems. This value is adjusted to 128 for very small machines
- * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
- * Further increasing requires to change hash table size.
- */
-int sysctl_max_syn_backlog = 256;
-
 struct request_sock_ops tcp_request_sock_ops = {
 	.family		=	PF_INET,
 	.obj_size	=	sizeof(struct tcp_request_sock),
@@ -2662,7 +2647,6 @@ EXPORT_SYMBOL(tcp_proc_register);
 EXPORT_SYMBOL(tcp_proc_unregister);
 #endif
 EXPORT_SYMBOL(sysctl_local_port_range);
-EXPORT_SYMBOL(sysctl_max_syn_backlog);
 EXPORT_SYMBOL(sysctl_tcp_low_latency);
 EXPORT_SYMBOL(sysctl_tcp_tw_reuse);