[CRIU] [PATCH] criu: tty -- Restore tty params synchronously

[Pavel Emelyanov]

On 04/21/2016 05:10 PM, Cyrill Gorcunov wrote:
> Async call to do_restore_tty_parms may have a side effect -- the caller
> doesn't wait for its completion and continue processing tty associated
> with the fd. userns_call carries own copy of file descriptor and if
> main code in tty fails then both slave and master may be closed
> and only one file descriptor remains: the one which userns carries,
> but the terminal already dead, so when we call do_restore_tty_parms
> on it we get -EIO.

But the restore fails anyway, so we do we care?

> Thus simply run params restoration on peers in sync'ed way when we
> know terminal peers both exist and valid.
> 
> https://jira.sw.ru/browse/PSBM-46382
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
> ---
>  criu/tty.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/criu/tty.c b/criu/tty.c
> index 68d7ba3..430a2c8 100644
> --- a/criu/tty.c
> +++ b/criu/tty.c
> @@ -786,7 +786,7 @@ static int restore_tty_params(int fd, struct tty_info *info)
>  		winsize_copy(&p.w, info->tie->winsize);
>  	}
>  
> -	return userns_call(do_restore_tty_parms, UNS_ASYNC, &p, sizeof(p), fd);
> +	return userns_call(do_restore_tty_parms, 0, &p, sizeof(p), fd);
>  }
>  
>  static int pty_open_slaves(struct tty_info *info)
>