Subject: Re: [PATCH net] net:sysctl fix the confusing corner of tcp_mem

From: Sergei Shtylyov <[email-masked]>
Date: Wed, 9 Dec 2015 16:47:34 +0300

Hello.

On 12/9/2015 5:01 AM, Wang Yufen wrote:

> From: Yufen Wang <[email-masked]>
>
> I tried on linux-4.1:
>      linux:~# cat /proc/sys/net/ipv4/tcp_mem
>      8388608	12582912	16777216
>      linux:~# echo 1234 >/proc/sys/net/ipv4/tcp_mem
>      -bash: echo: write error: Invalid argument
>      linux:~# cat /proc/sys/net/ipv4/tcp_mem
>      1234	12582912	16777216
>
> the echo operation got error, but value already written to tcp_mem.
> If a write() returns an error like EINVAL, we expect no change occurred.
> This patch fix the confusing corner and makes __do_proc_doulongvec_minmax
> works the same as __do_proc_dointvec
>
> Signed-off-by: Yufen Wang <[email-masked]>
> Cc: Eric Dumazet <[email-masked]>
> Cc: "Eric W. Biederman" <[email-masked]>
> ---
>   kernel/sysctl.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index c3eee4c..e3ee4be 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2318,6 +2318,8 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
>   			bool neg;
>
>   			left -= proc_skip_spaces(&kbuf);
> +                        if (!left)
> +                                break;

     Please use tabs for indentation, not spaces.

[...]

MBR, Sergei