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d4697bc9 | 1 | /* Copyright (C) 2003-2014 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> | |
22 | #include <pthreadP.h> | |
23 | ||
24 | ||
25 | /* Wait on barrier. */ | |
26 | int | |
27 | pthread_barrier_wait (barrier) | |
28 | pthread_barrier_t *barrier; | |
29 | { | |
30 | struct pthread_barrier *ibarrier = (struct pthread_barrier *) barrier; | |
37c054c7 | 31 | int result = 0; |
a88c9263 UD |
32 | |
33 | /* Make sure we are alone. */ | |
e51deae7 | 34 | lll_lock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG); |
a88c9263 UD |
35 | |
36 | /* One more arrival. */ | |
37 | --ibarrier->left; | |
38 | ||
39 | /* Are these all? */ | |
40 | if (ibarrier->left == 0) | |
41 | { | |
37c054c7 | 42 | /* Yes. Increment the event counter to avoid invalid wake-ups and |
a88c9263 UD |
43 | tell the current waiters that it is their turn. */ |
44 | ++ibarrier->curr_event; | |
45 | ||
46 | /* Wake up everybody. */ | |
835abc5c | 47 | lll_futex_wake (&ibarrier->curr_event, INT_MAX, |
e51deae7 | 48 | ibarrier->private ^ FUTEX_PRIVATE_FLAG); |
a88c9263 | 49 | |
a88c9263 | 50 | /* This is the thread which finished the serialization. */ |
37c054c7 | 51 | result = PTHREAD_BARRIER_SERIAL_THREAD; |
a88c9263 | 52 | } |
37c054c7 | 53 | else |
a88c9263 | 54 | { |
37c054c7 UD |
55 | /* The number of the event we are waiting for. The barrier's event |
56 | number must be bumped before we continue. */ | |
57 | unsigned int event = ibarrier->curr_event; | |
37c054c7 | 58 | |
33ab3b66 | 59 | /* Before suspending, make the barrier available to others. */ |
e51deae7 | 60 | lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG); |
37c054c7 | 61 | |
33ab3b66 UD |
62 | /* Wait for the event counter of the barrier to change. */ |
63 | do | |
835abc5c | 64 | lll_futex_wait (&ibarrier->curr_event, event, |
e51deae7 | 65 | ibarrier->private ^ FUTEX_PRIVATE_FLAG); |
37c054c7 | 66 | while (event == ibarrier->curr_event); |
a88c9263 | 67 | } |
a88c9263 | 68 | |
37c054c7 UD |
69 | /* Make sure the init_count is stored locally or in a register. */ |
70 | unsigned int init_count = ibarrier->init_count; | |
71 | ||
72 | /* If this was the last woken thread, unlock. */ | |
7ba0e52c | 73 | if (atomic_increment_val (&ibarrier->left) == init_count) |
37c054c7 | 74 | /* We are done. */ |
e51deae7 | 75 | lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG); |
a88c9263 | 76 | |
37c054c7 | 77 | return result; |
a88c9263 | 78 | } |