net: Kill ratelimit.h dependency in linux/net.h

Ingo Molnar noticed that we have this unnecessary ratelimit.h
dependency in linux/net.h, which hid compilation problems from
people doing builds only with CONFIG_NET enabled.

Move this stuff out to a seperate net/net_ratelimit.h file and
include that in the only two places where this thing is needed.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>

include/linux/net.h

@@ -289,11 +289,5 @@ extern int kernel_sock_shutdown(struct socket *sock,
 	MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto) \
 		     "-type-" __stringify(type))
 
-#ifdef CONFIG_SYSCTL
-#include <linux/sysctl.h>
-#include <linux/ratelimit.h>
-extern struct ratelimit_state net_ratelimit_state;
-#endif
-
 #endif /* __KERNEL__ */
 #endif	/* _LINUX_NET_H */

include/net/net_ratelimit.h

+#ifndef _LINUX_NET_RATELIMIT_H
+#define _LINUX_NET_RATELIMIT_H
+
+#include <linux/ratelimit.h>
+
+extern struct ratelimit_state net_ratelimit_state;
+
+#endif	/* _LINUX_NET_RATELIMIT_H */

net/core/sysctl_net_core.c

@@ -17,6 +17,7 @@
 
 #include <net/ip.h>
 #include <net/sock.h>
+#include <net/net_ratelimit.h>
 
 #ifdef CONFIG_RPS
 static int rps_sock_flow_sysctl(ctl_table *table, int write,

net/core/utils.c

@@ -27,6 +27,7 @@
 #include <linux/ratelimit.h>
 
 #include <net/sock.h>
+#include <net/net_ratelimit.h>
 
 #include <asm/byteorder.h>
 #include <asm/system.h>