net/ipv4: replace simple_strtoul with kstrtoul

Replace simple_strtoul with kstrtoul in three similar occurrences, all setup
handlers:
* route.c: set_rhash_entries
* tcp.c: set_thash_entries
* udp.c: set_uhash_entries

Also check if the conversion failed.
Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/route.c

@@ -3408,9 +3408,15 @@ struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
 static __initdata unsigned long rhash_entries;
 static int __init set_rhash_entries(char *str)
 {
+	ssize_t ret;
+
 	if (!str)
 		return 0;
-	rhash_entries = simple_strtoul(str, &str, 0);
+
+	ret = kstrtoul(str, 0, &rhash_entries);
+	if (ret)
+		return 0;
+
 	return 1;
 }
 __setup("rhash_entries=", set_rhash_entries);

net/ipv4/tcp.c

@@ -3462,9 +3462,15 @@ extern struct tcp_congestion_ops tcp_reno;
 static __initdata unsigned long thash_entries;
 static int __init set_thash_entries(char *str)
 {
+	ssize_t ret;
+
 	if (!str)
 		return 0;
-	thash_entries = simple_strtoul(str, &str, 0);
+
+	ret = kstrtoul(str, 0, &thash_entries);
+	if (ret)
+		return 0;
+
 	return 1;
 }
 __setup("thash_entries=", set_thash_entries);

net/ipv4/udp.c

@@ -2173,9 +2173,15 @@ void udp4_proc_exit(void)
 static __initdata unsigned long uhash_entries;
 static int __init set_uhash_entries(char *str)
 {
+	ssize_t ret;
+
 	if (!str)
 		return 0;
-	uhash_entries = simple_strtoul(str, &str, 0);
+
+	ret = kstrtoul(str, 0, &uhash_entries);
+	if (ret)
+		return 0;
+
 	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
 		uhash_entries = UDP_HTABLE_SIZE_MIN;
 	return 1;