tcp: convert tcp_comp_sack_nr sysctl to u8

tcp_comp_sack_nr max value was already 255.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -171,12 +171,12 @@ struct netns_ipv4 {
 	u8 sysctl_tcp_min_tso_segs;
 	u8 sysctl_tcp_autocorking;
 	u8 sysctl_tcp_reflect_tos;
+	u8 sysctl_tcp_comp_sack_nr;
 	int sysctl_tcp_invalid_ratelimit;
 	int sysctl_tcp_pacing_ss_ratio;
 	int sysctl_tcp_pacing_ca_ratio;
 	int sysctl_tcp_wmem[3];
 	int sysctl_tcp_rmem[3];
-	int sysctl_tcp_comp_sack_nr;
 	unsigned long sysctl_tcp_comp_sack_delay_ns;
 	unsigned long sysctl_tcp_comp_sack_slack_ns;
 	int sysctl_max_syn_backlog;

net/ipv4/sysctl_net_ipv4.c

@@ -46,7 +46,6 @@ static int tcp_syn_retries_min = 1;
 static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
 static int ip_ping_group_range_min[] = { 0, 0 };
 static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
-static int comp_sack_nr_max = 255;
 static u32 u32_max_div_HZ = UINT_MAX / HZ;
 static int one_day_secs = 24 * 3600;
 
@@ -1330,11 +1329,10 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "tcp_comp_sack_nr",
 		.data		= &init_net.ipv4.sysctl_tcp_comp_sack_nr,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &comp_sack_nr_max,
 	},
 	{
 		.procname       = "tcp_reflect_tos",