[v2] sysdeps/nanosleep: Use clock_nanosleep_time64 if avaliable

  On 24/10/2019 20:41, Alistair Francis wrote:
> diff --git a/sysdeps/unix/sysv/linux/nanosleep.c b/sysdeps/unix/sysv/linux/nanosleep.c
> index 6787909248f..10a6d57a1de 100644
> --- a/sysdeps/unix/sysv/linux/nanosleep.c
> +++ b/sysdeps/unix/sysv/linux/nanosleep.c
> @@ -17,15 +17,76 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <time.h>
> +#include <kernel-features.h>
>  #include <sysdep-cancel.h>
>  #include <not-cancel.h>
>  
>  /* Pause execution for a number of nanoseconds.  */
>  int
> +__nanosleep_time64 (const struct __timespec64 *requested_time,
> +                    struct __timespec64 *remaining)
> +{
> +#if defined(__ASSUME_TIME64_SYSCALLS)
> +# ifndef __NR_clock_nanosleep_time64
> +#  define __NR_clock_nanosleep_time64 __NR_clock_nanosleep
> +# endif
> +  return SYSCALL_CANCEL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
> +                         requested_time, remaining);
> +#else
> +# ifdef __NR_clock_nanosleep_time64
> +  long int ret_64;
> +
> +  ret_64 = SYSCALL_CANCEL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
> +                           requested_time, remaining);
> +
> +  if (ret_64 == 0 || errno != ENOSYS)
> +    return ret_64;
> +# endif /* __NR_clock_nanosleep_time64 */
> +  int ret;
> +  struct timespec ts32, tr32;
> +
> +  if (! in_time_t_range (requested_time->tv_sec))
> +    {
> +      __set_errno (EOVERFLOW);
> +      return -1;
> +    }
> +
> +  ts32 = valid_timespec64_to_timespec (*requested_time);
> +  ret = SYSCALL_CANCEL (nanosleep, &ts32, &tr32);
> +
> +  if ((ret == 0 || errno != ENOSYS) && remaining)
> +    *remaining = valid_timespec_to_timespec64 (tr32);
> +
> +  return ret;
> +#endif /* __ASSUME_TIME64_SYSCALLS */
> +}
> +
> +#if __TIMESIZE != 64
> +int
>  __nanosleep (const struct timespec *requested_time,
> -	     struct timespec *remaining)
> +             struct timespec *remaining)
>  {
> -  return SYSCALL_CANCEL (nanosleep, requested_time, remaining);
> +  int r;
> +  struct __timespec64 treq64, trem64;
> +
> +  treq64 = valid_timespec_to_timespec64 (*requested_time);
> +  r = __nanosleep_time64 (&treq64, &trem64);
> +
> +  if (r == 0 || errno != ENOSYS)
> +    {
> +      if (! in_time_t_range (trem64.tv_sec))
> +        {
> +          __set_errno (EOVERFLOW);
> +          return -1;
> +        }
> +
> +      if (remaining)
> +        *remaining = valid_timespec64_to_timespec (trem64);
> +    }
> +
> +  return r;
>  }
> +#endif
> +
>  hidden_def (__nanosleep)
>  weak_alias (__nanosleep, nanosleep)

There is no need to replicate all the syscall logic, nanosleep can be implemented
with __clock_nanosleep.  You can do:

int
__nanosleep (const struct timespec *requested_time,
             struct timespec *remaining)
{
  int ret = __clock_nanosleep (CLOCK_REALTIME, 0, requested_time, remaining);
  if (ret != 0)
    {
      __set_errno (-ret);
      return -1;
    }
  return ret;
}

I think we can even make it the default version, thus removing the linux
specific file.

> diff --git a/sysdeps/unix/sysv/linux/nanosleep_nocancel.c b/sysdeps/unix/sysv/linux/nanosleep_nocancel.c
> index d6442bf4f7f..1a6c6c0a48a 100644
> --- a/sysdeps/unix/sysv/linux/nanosleep_nocancel.c
> +++ b/sysdeps/unix/sysv/linux/nanosleep_nocancel.c
> @@ -17,13 +17,74 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <time.h>
> +#include <kernel-features.h>
>  #include <sysdep-cancel.h>
>  #include <not-cancel.h>
>  
> +int
> +__nanosleep_nocancel_time64 (const struct __timespec64 *requested_time,
> +                             struct __timespec64 *remaining)
> +{
> +#ifdef __ASSUME_TIME64_SYSCALLS
> +# ifndef __NR_clock_nanosleep_time64
> +#  define __NR_clock_nanosleep_time64 __NR_clock_nanosleep
> +# endif
> +  return INLINE_SYSCALL_CALL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
> +                              requested_time, remaining);
> +#else
> +# ifdef __NR_clock_nanosleep_time64
> +  long int ret_64;
> +
> +  ret_64 = INLINE_SYSCALL_CALL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
> +                                requested_time, remaining);
> +
> +  if (ret_64 == 0 || errno != ENOSYS)
> +    return ret_64;
> +# endif /* __NR_clock_nanosleep_time64 */
> +  int ret;
> +  struct timespec ts32, tr32;
> +
> +  if (! in_time_t_range (requested_time->tv_sec))
> +    {
> +      __set_errno (EOVERFLOW);
> +      return -1;
> +    }
> +
> +  ts32 = valid_timespec64_to_timespec (*requested_time);
> +  ret = INLINE_SYSCALL_CALL (nanosleep, &ts32, &tr32);
> +
> +  if (ret == 0 || errno != ENOSYS)
> +    *remaining = valid_timespec_to_timespec64 (tr32);
> +
> +  return ret;
> +#endif /* __ASSUME_TIME64_SYSCALLS */
> +}
> +
> +#if __TIMESIZE != 64
>  int
>  __nanosleep_nocancel (const struct timespec *requested_time,
> -		      struct timespec *remaining)
> +                      struct timespec *remaining)
>  {
> -  return INLINE_SYSCALL_CALL (nanosleep, requested_time, remaining);
> +  int ret;
> +  struct __timespec64 treq64, trem64;
> +
> +  treq64 = valid_timespec_to_timespec64 (*requested_time);
> +  ret = __nanosleep_nocancel_time64 (&treq64, &trem64);
> +
> +  if (ret == 0 || errno != ENOSYS)
> +    {
> +      if (! in_time_t_range (trem64.tv_sec))
> +        {
> +          __set_errno (EOVERFLOW);
> +          return -1;
> +        }
> +
> +      if (remaining)
> +        *remaining = valid_timespec64_to_timespec (trem64);
> +    }
> +
> +  return ret;
>  }
> +#endif
> +
>  hidden_def (__nanosleep_nocancel)
> 

The __nanosleep_nocancel is just used priority mutex for pthread_mutex_timedlock,
and I am almost sure that we can replace the code path with __lll_clocklock_wait.
Something like the below.

If you like I can sent it as a cleanup patch, since it would require some more
work to remove the __nanosleep_nocancel internal definitions as well.

--

[v2] sysdeps/nanosleep: Use clock_nanosleep_time64 if avaliable

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