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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
95 lines
3.3 KiB
C
95 lines
3.3 KiB
C
/* Copyright (C) 2003-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <endian.h>
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#include <errno.h>
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#include <sysdep.h>
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#include <futex-internal.h>
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#include <pthread.h>
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#include <pthreadP.h>
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#include <stap-probe.h>
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#include <atomic.h>
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#include <shlib-compat.h>
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#include "pthread_cond_common.c"
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/* We do the following steps from __pthread_cond_signal in one critical
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section: (1) signal all waiters in G1, (2) close G1 so that it can become
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the new G2 and make G2 the new G1, and (3) signal all waiters in the new
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G1. We don't need to do all these steps if there are no waiters in G1
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and/or G2. See __pthread_cond_signal for further details. */
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int
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___pthread_cond_broadcast (pthread_cond_t *cond)
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{
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LIBC_PROBE (cond_broadcast, 1, cond);
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unsigned int wrefs = atomic_load_relaxed (&cond->__data.__wrefs);
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if (wrefs >> 3 == 0)
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return 0;
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int private = __condvar_get_private (wrefs);
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__condvar_acquire_lock (cond, private);
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unsigned long long int wseq = __condvar_load_wseq_relaxed (cond);
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unsigned int g2 = wseq & 1;
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unsigned int g1 = g2 ^ 1;
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wseq >>= 1;
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bool do_futex_wake = false;
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/* Step (1): signal all waiters remaining in G1. */
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if (cond->__data.__g_size[g1] != 0)
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{
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/* Add as many signals as the remaining size of the group. */
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atomic_fetch_add_relaxed (cond->__data.__g_signals + g1,
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cond->__data.__g_size[g1] << 1);
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cond->__data.__g_size[g1] = 0;
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/* We need to wake G1 waiters before we quiesce G1 below. */
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/* TODO Only set it if there are indeed futex waiters. We could
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also try to move this out of the critical section in cases when
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G2 is empty (and we don't need to quiesce). */
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futex_wake (cond->__data.__g_signals + g1, INT_MAX, private);
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}
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/* G1 is complete. Step (2) is next unless there are no waiters in G2, in
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which case we can stop. */
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if (__condvar_quiesce_and_switch_g1 (cond, wseq, &g1, private))
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{
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/* Step (3): Send signals to all waiters in the old G2 / new G1. */
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atomic_fetch_add_relaxed (cond->__data.__g_signals + g1,
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cond->__data.__g_size[g1] << 1);
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cond->__data.__g_size[g1] = 0;
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/* TODO Only set it if there are indeed futex waiters. */
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do_futex_wake = true;
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}
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__condvar_release_lock (cond, private);
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if (do_futex_wake)
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futex_wake (cond->__data.__g_signals + g1, INT_MAX, private);
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return 0;
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}
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versioned_symbol (libc, ___pthread_cond_broadcast,
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pthread_cond_broadcast, GLIBC_2_3_2);
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libc_hidden_ver (___pthread_cond_broadcast, __pthread_cond_broadcast)
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#ifndef SHARED
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strong_alias (___pthread_cond_broadcast, __pthread_cond_broadcast)
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#endif
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