net-tcp: /proc/sys/net/ipv4/tcp_probe_interval is a u32 not int

(fix documentation and sysctl access to treat it as such)

Tested:
  # zcat /proc/config.gz | egrep ^CONFIG_HZ
  CONFIG_HZ_1000=y
  CONFIG_HZ=1000
  # echo $[(1<<32)/1000 + 1] | tee /proc/sys/net/ipv4/tcp_probe_interval
  4294968
  tee: /proc/sys/net/ipv4/tcp_probe_interval: Invalid argument
  # echo $[(1<<32)/1000] | tee /proc/sys/net/ipv4/tcp_probe_interval
  4294967
  # echo 0 | tee /proc/sys/net/ipv4/tcp_probe_interval
  # echo -1 | tee /proc/sys/net/ipv4/tcp_probe_interval
  -1
  tee: /proc/sys/net/ipv4/tcp_probe_interval: Invalid argument

Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 8313a63..960de8f 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -425,7 +425,7 @@ tcp_mtu_probing - INTEGER
          1 - Disabled by default, enabled when an ICMP black hole detected
          2 - Always enabled, use initial MSS of tcp_base_mss.
 
-tcp_probe_interval - INTEGER
+tcp_probe_interval - UNSIGNED INTEGER
        Controls how often to start TCP Packetization-Layer Path MTU
        Discovery reprobe. The default is reprobing every 10 minutes as
        per RFC4821.

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index b92f422..891ed2f 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -48,6 +48,7 @@ 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;
 
 /* obsolete */
 static int sysctl_tcp_low_latency __read_mostly;
@@ -745,9 +746,10 @@ static struct ctl_table ipv4_net_table[] = {
        {
                .procname       = "tcp_probe_interval",
                .data           = &init_net.ipv4.sysctl_tcp_probe_interval,
-               .maxlen         = sizeof(int),
+               .maxlen         = sizeof(u32),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec,
+               .proc_handler   = proc_douintvec_minmax,
+               .extra2         = &u32_max_div_HZ,
        },
        {
                .procname       = "igmp_link_local_mcast_reports",