1/* Get priority ceiling setting from pthread_mutexattr_t.
2 Copyright (C) 2006-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <pthreadP.h>
21#include <atomic.h>
22
23
24int
25pthread_mutexattr_getprioceiling (const pthread_mutexattr_t *attr,
26 int *prioceiling)
27{
28 const struct pthread_mutexattr *iattr;
29 int ceiling;
30
31 iattr = (const struct pthread_mutexattr *) attr;
32
33 ceiling = ((iattr->mutexkind & PTHREAD_MUTEXATTR_PRIO_CEILING_MASK)
34 >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT);
35
36 if (! ceiling)
37 {
38 /* See __init_sched_fifo_prio. */
39 if (atomic_load_relaxed (&__sched_fifo_min_prio) == -1)
40 __init_sched_fifo_prio ();
41 if (ceiling < atomic_load_relaxed (&__sched_fifo_min_prio))
42 ceiling = atomic_load_relaxed (&__sched_fifo_min_prio);
43 }
44
45 *prioceiling = ceiling;
46
47 return 0;
48}
49