glibc/nptl/lll_timedlock_wait.c
Adhemerval Zanella 215078017f nptl: Replace non cancellable pause/nanosleep with futex
To help y2038 work avoid duplicate all the logic of nanosleep on
non cancellable version, the patch replace it with a new futex
operation, lll_timedwait.  The changes are:

  - Add a expected value for __lll_clocklock_wait, so it can be used
    to wait for generic values.

  - Remove its internal atomic operation and move the logic to
    __lll_clocklock.  It makes __lll_clocklock_wait even more generic
    and __lll_clocklock slight faster on fast-path (since it won't
    require a function call anymore).

  - Add lll_timedwait, which uses __lll_clocklock_wait, to replace both
    __pause_nocancel and __nanosleep_nocancel.

It also allows remove the sparc32 __lll_clocklock_wait implementation
(since it is similar to the generic one).

Checked on x86_64-linux-gnu, sparcv9-linux-gnu, and i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2019-10-31 11:09:01 -03:00

63 lines
1.9 KiB
C

/* Timed low level locking for pthread library. Generic futex-using version.
Copyright (C) 2003-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <atomic.h>
#include <errno.h>
#include <lowlevellock.h>
#include <sys/time.h>
#include <time.h>
int
__lll_clocklock_wait (int *futex, int val, clockid_t clockid,
const struct timespec *abstime, int private)
{
struct timespec ts, *tsp = NULL;
if (abstime != NULL)
{
/* Reject invalid timeouts. */
if (! valid_nanoseconds (abstime->tv_nsec))
return EINVAL;
/* Get the current time. This can only fail if clockid is not valid. */
if (__glibc_unlikely (__clock_gettime (clockid, &ts) != 0))
return EINVAL;
/* Compute relative timeout. */
ts.tv_sec = abstime->tv_sec - ts.tv_sec;
ts.tv_nsec = abstime->tv_nsec - ts.tv_nsec;
if (ts.tv_nsec < 0)
{
ts.tv_nsec += 1000000000;
--ts.tv_sec;
}
if (ts.tv_sec < 0)
return ETIMEDOUT;
tsp = &ts;
}
/* If *futex == val, wait until woken or timeout. */
lll_futex_timed_wait (futex, val, tsp, private);
return 0;
}