[PATCH 01/13] linux: Remove unused internal futex functions

Lukasz Majewski lukma@denx.de
Tue Nov 24 17:51:11 GMT 2020


Hi Adhemerval,

> The __futex_abstimed_wait usage was remove with 3102e28bd11 and the
> __futex_abstimed_wait_cancelable by 323592fdc92 and b8d3e8fbaac.
> The futex_lock_pi can be replaced by a futex_lock_pi64.
> 
> Checked on x86_64-linux-gnu and i686-linux-gnu.
> ---
>  nptl/pthread_mutex_lock.c     |  3 +-
>  sysdeps/nptl/futex-internal.h | 98
> ----------------------------------- 2 files changed, 1 insertion(+),
> 100 deletions(-)
> 
> diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
> index fac774e608..0439002454 100644
> --- a/nptl/pthread_mutex_lock.c
> +++ b/nptl/pthread_mutex_lock.c
> @@ -413,8 +413,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
>  	    int private = (robust
>  			   ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex)
>  			   : PTHREAD_MUTEX_PSHARED (mutex));
> -	    int e = futex_lock_pi ((unsigned int *)
> &mutex->__data.__lock,
> -				   NULL, private);
> +	    int e = futex_lock_pi64 (&mutex->__data.__lock, NULL,
> private); if (e == ESRCH || e == EDEADLK)
>  	      {
>  		assert (e != EDEADLK
> diff --git a/sysdeps/nptl/futex-internal.h
> b/sysdeps/nptl/futex-internal.h index c27d0cdac8..21e3b74be6 100644
> --- a/sysdeps/nptl/futex-internal.h
> +++ b/sysdeps/nptl/futex-internal.h
> @@ -275,76 +275,6 @@ futex_abstimed_supported_clockid (clockid_t
> clockid) return lll_futex_supported_clockid (clockid);
>  }
>  
> -/* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an
> -   absolute point in time; a call will time out after this point in
> time.  */ -static __always_inline int
> -futex_abstimed_wait (unsigned int* futex_word, unsigned int expected,
> -		     clockid_t clockid,
> -		     const struct timespec* abstime, int private)
> -{
> -  /* Work around the fact that the kernel rejects negative timeout
> values
> -     despite them being valid.  */
> -  if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
> -    return ETIMEDOUT;
> -  int err = lll_futex_clock_wait_bitset (futex_word, expected,
> -					 clockid, abstime,
> -					 private);
> -  switch (err)
> -    {
> -    case 0:
> -    case -EAGAIN:
> -    case -EINTR:
> -    case -ETIMEDOUT:
> -      return -err;
> -
> -    case -EFAULT: /* Must have been caused by a glibc or application
> bug.  */
> -    case -EINVAL: /* Either due to wrong alignment, unsupported
> -		     clockid or due to the timeout not being
> -		     normalized. Must have been caused by a glibc or
> -		     application bug.  */
> -    case -ENOSYS: /* Must have been caused by a glibc bug.  */
> -    /* No other errors are documented at this time.  */
> -    default:
> -      futex_fatal_error ();
> -    }
> -}
> -
> -/* Like futex_reltimed_wait but is a POSIX cancellation point.  */
> -static __always_inline int
> -futex_abstimed_wait_cancelable (unsigned int* futex_word,
> -				unsigned int expected,
> -				clockid_t clockid,
> -			        const struct timespec* abstime, int
> private) -{
> -  /* Work around the fact that the kernel rejects negative timeout
> values
> -     despite them being valid.  */
> -  if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
> -    return ETIMEDOUT;
> -  int oldtype;
> -  oldtype = __pthread_enable_asynccancel ();
> -  int err = lll_futex_clock_wait_bitset (futex_word, expected,
> -					clockid, abstime,
> -					private);
> -  __pthread_disable_asynccancel (oldtype);
> -  switch (err)
> -    {
> -    case 0:
> -    case -EAGAIN:
> -    case -EINTR:
> -    case -ETIMEDOUT:
> -      return -err;
> -
> -    case -EFAULT: /* Must have been caused by a glibc or application
> bug.  */
> -    case -EINVAL: /* Either due to wrong alignment or due to the
> timeout not
> -		     being normalized.  Must have been caused by a
> glibc or
> -		     application bug.  */
> -    case -ENOSYS: /* Must have been caused by a glibc bug.  */
> -    /* No other errors are documented at this time.  */
> -    default:
> -      futex_fatal_error ();
> -    }
> -}
> -
>  /* Atomically wrt other futex operations on the same futex, this
> unblocks the specified number of processes, or all processes blocked
> on this futex if there are fewer than the specified number.
> Semantically, this is @@ -410,34 +340,6 @@ futex_wake (unsigned int*
> futex_word, int processes_to_wake, int private) futex.
>       - ETIMEDOUT if the ABSTIME expires.
>  */
> -static __always_inline int
> -futex_lock_pi (unsigned int *futex_word, const struct timespec
> *abstime,
> -	       int private)
> -{
> -  int err = lll_futex_timed_lock_pi (futex_word, abstime, private);
> -  switch (err)
> -    {
> -    case 0:
> -    case -EAGAIN:
> -    case -EINTR:
> -    case -ETIMEDOUT:
> -    case -ESRCH:
> -    case -EDEADLK:
> -    case -EINVAL: /* This indicates either state corruption or that
> the kernel
> -		     found a waiter on futex address which is
> waiting via
> -		     FUTEX_WAIT or FUTEX_WAIT_BITSET.  This is
> reported on
> -		     some futex_lock_pi usage
> (pthread_mutex_timedlock for
> -		     instance).  */
> -      return -err;
> -
> -    case -EFAULT: /* Must have been caused by a glibc or application
> bug.  */
> -    case -ENOSYS: /* Must have been caused by a glibc bug.  */
> -    /* No other errors are documented at this time.  */
> -    default:
> -      futex_fatal_error ();
> -    }
> -}
> -
>  static __always_inline int
>  futex_lock_pi64 (int *futex_word, const struct __timespec64 *abstime,
>                   int private)

It is great that we can consolidate the thread code and remove one not
needed.

Reviewed-by: Lukasz Majewski <lukma@denx.de>


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
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