Re: [PATCH 05/32] timerfd/timens: Take into account ns clock offsets

[Cyrill Gorcunov <gorcunov@gmail.com>]

On Wed, Feb 06, 2019 at 12:10:39AM +0000, Dmitry Safonov wrote:
> From: Andrei Vagin <avagin@gmail.com>
> 
> Make timerfd respect timens offsets.
> Provide two helpers timens_clock_to_host() timens_clock_from_host() that
> are useful to wire up timens to different kernel subsystems.
> Following patches will use timens_clock_from_host(), added here for
> completeness.
> 
> Signed-off-by: Andrei Vagin <avagin@openvz.org>
> Co-developed-by: Dmitry Safonov <dima@arista.com>
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---
>  fs/timerfd.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/timerfd.c b/fs/timerfd.c
> index 803ca070d42e..c7ae1e371912 100644
> --- a/fs/timerfd.c
> +++ b/fs/timerfd.c
> @@ -26,6 +26,7 @@
>  #include <linux/syscalls.h>
>  #include <linux/compat.h>
>  #include <linux/rcupdate.h>
> +#include <linux/time_namespace.h>
>  
>  struct timerfd_ctx {
>  	union {
> @@ -433,22 +434,27 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
>  }
>  
>  static int do_timerfd_settime(int ufd, int flags, 
> -		const struct itimerspec64 *new,
> +		struct itimerspec64 *new,
>  		struct itimerspec64 *old)
>  {
>  	struct fd f;
>  	struct timerfd_ctx *ctx;
>  	int ret;
>  
> -	if ((flags & ~TFD_SETTIME_FLAGS) ||
> -		 !itimerspec64_valid(new))
> -		return -EINVAL;

Please don't defer this early test of a @flags value. Otherwise
if @flags is invalid you continue fget/put/clock-to-host even
if result will be dropped out then.