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f7a9f785 | 1 | /* Copyright (C) 2003-2016 Free Software Foundation, Inc. |
a88c9263 UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
a88c9263 UD |
18 | |
19 | #include <errno.h> | |
20 | #include <sysdep.h> | |
21 | #include <lowlevellock.h> | |
a2f0363f | 22 | #include <futex-internal.h> |
a88c9263 UD |
23 | #include <pthreadP.h> |
24 | ||
25 | ||
26 | /* Wait on barrier. */ | |
27 | int | |
9d46370c | 28 | __pthread_barrier_wait (pthread_barrier_t *barrier) |
a88c9263 UD |
29 | { |
30 | struct pthread_barrier *ibarrier = (struct pthread_barrier *) barrier; | |
37c054c7 | 31 | int result = 0; |
a2f0363f TR |
32 | int lll_private = ibarrier->private ^ FUTEX_PRIVATE_FLAG; |
33 | int futex_private = (lll_private == LLL_PRIVATE | |
34 | ? FUTEX_PRIVATE : FUTEX_SHARED); | |
a88c9263 UD |
35 | |
36 | /* Make sure we are alone. */ | |
a2f0363f | 37 | lll_lock (ibarrier->lock, lll_private); |
a88c9263 UD |
38 | |
39 | /* One more arrival. */ | |
40 | --ibarrier->left; | |
41 | ||
42 | /* Are these all? */ | |
43 | if (ibarrier->left == 0) | |
44 | { | |
37c054c7 | 45 | /* Yes. Increment the event counter to avoid invalid wake-ups and |
a88c9263 UD |
46 | tell the current waiters that it is their turn. */ |
47 | ++ibarrier->curr_event; | |
48 | ||
49 | /* Wake up everybody. */ | |
a2f0363f | 50 | futex_wake (&ibarrier->curr_event, INT_MAX, futex_private); |
a88c9263 | 51 | |
a88c9263 | 52 | /* This is the thread which finished the serialization. */ |
37c054c7 | 53 | result = PTHREAD_BARRIER_SERIAL_THREAD; |
a88c9263 | 54 | } |
37c054c7 | 55 | else |
a88c9263 | 56 | { |
37c054c7 UD |
57 | /* The number of the event we are waiting for. The barrier's event |
58 | number must be bumped before we continue. */ | |
59 | unsigned int event = ibarrier->curr_event; | |
37c054c7 | 60 | |
33ab3b66 | 61 | /* Before suspending, make the barrier available to others. */ |
a2f0363f | 62 | lll_unlock (ibarrier->lock, lll_private); |
37c054c7 | 63 | |
33ab3b66 UD |
64 | /* Wait for the event counter of the barrier to change. */ |
65 | do | |
a2f0363f | 66 | futex_wait_simple (&ibarrier->curr_event, event, futex_private); |
37c054c7 | 67 | while (event == ibarrier->curr_event); |
a88c9263 | 68 | } |
a88c9263 | 69 | |
37c054c7 UD |
70 | /* Make sure the init_count is stored locally or in a register. */ |
71 | unsigned int init_count = ibarrier->init_count; | |
72 | ||
73 | /* If this was the last woken thread, unlock. */ | |
7ba0e52c | 74 | if (atomic_increment_val (&ibarrier->left) == init_count) |
37c054c7 | 75 | /* We are done. */ |
a2f0363f | 76 | lll_unlock (ibarrier->lock, lll_private); |
a88c9263 | 77 | |
37c054c7 | 78 | return result; |
a88c9263 | 79 | } |
90dd5913 | 80 | weak_alias (__pthread_barrier_wait, pthread_barrier_wait) |