2016-12-29 14:52:54

by Pavel Tikhomirov

Subject: [PATCH] ipv4: make tcp_notsent_lowat sysctl knob behave as true unsigned int

> cat /proc/sys/net/ipv4/tcp_notsent_lowat
-1
> echo 4294967295 > /proc/sys/net/ipv4/tcp_notsent_lowat
-bash: echo: write error: Invalid argument
> echo -2147483648 > /proc/sys/net/ipv4/tcp_notsent_lowat
> cat /proc/sys/net/ipv4/tcp_notsent_lowat
-2147483648

but in documentation we have "tcp_notsent_lowat - UNSIGNED INTEGER"

Signed-off-by: Pavel Tikhomirov <[email protected]>
---
net/ipv4/sysctl_net_ipv4.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 80bc36b..5361373 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -41,6 +41,7 @@ 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 unsigned int uint_max = UINT_MAX;

/* Update system visible IP port range */
static void set_local_port_range(struct net *net, int range[2])
@@ -958,7 +959,9 @@ static struct ctl_table ipv4_net_table[] = {
.data = &init_net.ipv4.sysctl_tcp_notsent_lowat,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_doulongvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &uint_max,
},
#ifdef CONFIG_IP_ROUTE_MULTIPATH
{
--
2.9.3

2016-12-30 20:23:29

by David Miller

Subject: Re: [PATCH] ipv4: make tcp_notsent_lowat sysctl knob behave as true unsigned int

From: Pavel Tikhomirov <[email protected]>
Date: Thu, 29 Dec 2016 17:35:07 +0300

> @@ -958,7 +959,9 @@ static struct ctl_table ipv4_net_table[] = {
> .data = &init_net.ipv4.sysctl_tcp_notsent_lowat,
> .maxlen = sizeof(unsigned int),
> .mode = 0644,
> - .proc_handler = proc_dointvec,
> + .proc_handler = proc_doulongvec_minmax,
> + .extra1 = &zero,
> + .extra2 = &uint_max,

It seems much simpler to use "proc_douintvec()" to fix this bug.

Doesn't it?