Re: [PATCH RESEND] pty: show associative slave of ptmx in fdinfo

[Greg KH]

On Thu, Jul 13, 2017 at 04:34:37AM +0900, Masatake YAMATO wrote:
> This patch adds "tty-index" field to /proc/PID/fdinfo/N if N
> specifies /dev/ptmx. The field shows the index of associative
> slave pts.
> 
> Though a minor number is given for each pts instance, ptmx is not.
> It means there is no way in user-space to know the association between
> file descriptors for pts/n and ptmx. (n = 0, 1, ...)
> 
> This is different from pipe. About pipe such association can be solved
> by inode of pipefs.
> 
> Providing the way to know the association between pts/n and ptmx helps
> users understand the status of running system. lsof can utilize this field.
> 
> Signed-off-by: Masatake YAMATO <yamato@xxxxxxxxxx>
> ---
>  drivers/tty/pty.c          | 12 +++++++++++-
>  drivers/tty/tty_io.c       | 15 +++++++++++++++
>  include/linux/tty_driver.h |  5 +++++
>  3 files changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
> index 6579957..9357c6a 100644
> --- a/drivers/tty/pty.c
> +++ b/drivers/tty/pty.c
> @@ -669,6 +669,13 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
>  	}
>  }
>  
> +#ifdef CONFIG_PROC_FS

There is no real need for all of the #ifdef everywhere here, if PROC_FS
is not enabled, the functions will just not be called, right?

Can you fix this up and resend a new version?

thanks,

greg k-h