nptl/pthread_mutexattr_setprioceiling.c

   1 /* Change priority ceiling setting in pthread_mutexattr_t.
   2    Copyright (C) 2006-2017 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    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <pthreadP.h>
  22 #include <atomic.h>
  23
  24
  25 int
  26 pthread_mutexattr_setprioceiling (pthread_mutexattr_t *attr, int prioceiling)
  27 {
  28   /* See __init_sched_fifo_prio.  */
  29   if (atomic_load_relaxed (&__sched_fifo_min_prio) == -1
  30       || atomic_load_relaxed (&__sched_fifo_max_prio) == -1)
  31     __init_sched_fifo_prio ();
  32
  33   if (__glibc_unlikely (prioceiling
  34                         < atomic_load_relaxed (&__sched_fifo_min_prio))
  35       || __glibc_unlikely (prioceiling
  36                            > atomic_load_relaxed (&__sched_fifo_max_prio))
  37       || __glibc_unlikely ((prioceiling
  38                             & (PTHREAD_MUTEXATTR_PRIO_CEILING_MASK
  39                                >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT))
  40                            != prioceiling))
  41     return EINVAL;
  42
  43   struct pthread_mutexattr *iattr = (struct pthread_mutexattr *) attr;
  44
  45   iattr->mutexkind = ((iattr->mutexkind & ~PTHREAD_MUTEXATTR_PRIO_CEILING_MASK)
  46                       | (prioceiling << PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT));
  47
  48   return 0;
  49 }