ipvs: Restrict connection table size via Kconfig

Instead of checking the value in include/net/ip_vs.h, we can just
restrict the range in our Kconfig file. This will prevent values outside
of the range early.
Signed-off-by: NSven Wegener <sven.wegener@stealer.net>
Reviewed-by: NJulius Volz <juliusv@google.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>

include/net/ip_vs.h

@@ -621,16 +621,8 @@ extern void ip_vs_init_hash_table(struct list_head *table, int rows);
 #ifndef CONFIG_IP_VS_TAB_BITS
 #define CONFIG_IP_VS_TAB_BITS   12
 #endif
-/* make sure that IP_VS_CONN_TAB_BITS is located in [8, 20] */
-#if CONFIG_IP_VS_TAB_BITS < 8
-#define IP_VS_CONN_TAB_BITS	8
-#endif
-#if CONFIG_IP_VS_TAB_BITS > 20
-#define IP_VS_CONN_TAB_BITS	20
-#endif
-#if 8 <= CONFIG_IP_VS_TAB_BITS && CONFIG_IP_VS_TAB_BITS <= 20
+
 #define IP_VS_CONN_TAB_BITS	CONFIG_IP_VS_TAB_BITS
-#endif
 #define IP_VS_CONN_TAB_SIZE     (1 << IP_VS_CONN_TAB_BITS)
 #define IP_VS_CONN_TAB_MASK     (IP_VS_CONN_TAB_SIZE - 1)
 

net/ipv4/ipvs/Kconfig

@@ -41,7 +41,8 @@ config	IP_VS_DEBUG
 
 config	IP_VS_TAB_BITS
 	int "IPVS connection table size (the Nth power of 2)"
-	default "12" 
+	range 8 20
+	default 12
 	---help---
 	  The IPVS connection hash table uses the chaining scheme to handle
 	  hash collisions. Using a big IPVS connection hash table will greatly