1*062c5bc4SJason Schmidlapp /*
2*062c5bc4SJason Schmidlapp * pthread_spin_destroy.c
3*062c5bc4SJason Schmidlapp *
4*062c5bc4SJason Schmidlapp * Description:
5*062c5bc4SJason Schmidlapp * This translation unit implements spin lock primitives.
6*062c5bc4SJason Schmidlapp *
7*062c5bc4SJason Schmidlapp * --------------------------------------------------------------------------
8*062c5bc4SJason Schmidlapp *
9*062c5bc4SJason Schmidlapp * Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
10*062c5bc4SJason Schmidlapp * Copyright(C) 2008 Jason Schmidlapp
11*062c5bc4SJason Schmidlapp *
12*062c5bc4SJason Schmidlapp * Contact Email: jschmidlapp@users.sourceforge.net
13*062c5bc4SJason Schmidlapp *
14*062c5bc4SJason Schmidlapp *
15*062c5bc4SJason Schmidlapp * Based upon Pthreads-win32 - POSIX Threads Library for Win32
16*062c5bc4SJason Schmidlapp * Copyright(C) 1998 John E. Bossom
17*062c5bc4SJason Schmidlapp * Copyright(C) 1999,2005 Pthreads-win32 contributors
18*062c5bc4SJason Schmidlapp *
19*062c5bc4SJason Schmidlapp * Contact Email: rpj@callisto.canberra.edu.au
20*062c5bc4SJason Schmidlapp *
21*062c5bc4SJason Schmidlapp * The original list of contributors to the Pthreads-win32 project
22*062c5bc4SJason Schmidlapp * is contained in the file CONTRIBUTORS.ptw32 included with the
23*062c5bc4SJason Schmidlapp * source code distribution. The list can also be seen at the
24*062c5bc4SJason Schmidlapp * following World Wide Web location:
25*062c5bc4SJason Schmidlapp * http://sources.redhat.com/pthreads-win32/contributors.html
26*062c5bc4SJason Schmidlapp *
27*062c5bc4SJason Schmidlapp * This library is free software; you can redistribute it and/or
28*062c5bc4SJason Schmidlapp * modify it under the terms of the GNU Lesser General Public
29*062c5bc4SJason Schmidlapp * License as published by the Free Software Foundation; either
30*062c5bc4SJason Schmidlapp * version 2 of the License, or (at your option) any later version.
31*062c5bc4SJason Schmidlapp *
32*062c5bc4SJason Schmidlapp * This library is distributed in the hope that it will be useful,
33*062c5bc4SJason Schmidlapp * but WITHOUT ANY WARRANTY; without even the implied warranty of
34*062c5bc4SJason Schmidlapp * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
35*062c5bc4SJason Schmidlapp * Lesser General Public License for more details.
36*062c5bc4SJason Schmidlapp *
37*062c5bc4SJason Schmidlapp * You should have received a copy of the GNU Lesser General Public
38*062c5bc4SJason Schmidlapp * License along with this library in the file COPYING.LIB;
39*062c5bc4SJason Schmidlapp * if not, write to the Free Software Foundation, Inc.,
40*062c5bc4SJason Schmidlapp * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
41*062c5bc4SJason Schmidlapp */
42*062c5bc4SJason Schmidlapp
43*062c5bc4SJason Schmidlapp #include <stdlib.h>
44*062c5bc4SJason Schmidlapp
45*062c5bc4SJason Schmidlapp #include "pthread.h"
46*062c5bc4SJason Schmidlapp #include "implement.h"
47*062c5bc4SJason Schmidlapp
48*062c5bc4SJason Schmidlapp
49*062c5bc4SJason Schmidlapp int
pthread_spin_destroy(pthread_spinlock_t * lock)50*062c5bc4SJason Schmidlapp pthread_spin_destroy (pthread_spinlock_t * lock)
51*062c5bc4SJason Schmidlapp {
52*062c5bc4SJason Schmidlapp register pthread_spinlock_t s;
53*062c5bc4SJason Schmidlapp int result = 0;
54*062c5bc4SJason Schmidlapp
55*062c5bc4SJason Schmidlapp if (lock == NULL || *lock == NULL)
56*062c5bc4SJason Schmidlapp {
57*062c5bc4SJason Schmidlapp return EINVAL;
58*062c5bc4SJason Schmidlapp }
59*062c5bc4SJason Schmidlapp
60*062c5bc4SJason Schmidlapp if ((s = *lock) != PTHREAD_SPINLOCK_INITIALIZER)
61*062c5bc4SJason Schmidlapp {
62*062c5bc4SJason Schmidlapp if (s->interlock == PTE_SPIN_USE_MUTEX)
63*062c5bc4SJason Schmidlapp {
64*062c5bc4SJason Schmidlapp result = pthread_mutex_destroy (&(s->u.mutex));
65*062c5bc4SJason Schmidlapp }
66*062c5bc4SJason Schmidlapp else if (PTE_SPIN_UNLOCKED !=
67*062c5bc4SJason Schmidlapp PTE_ATOMIC_COMPARE_EXCHANGE (
68*062c5bc4SJason Schmidlapp & (s->interlock),
69*062c5bc4SJason Schmidlapp (int) PTE_OBJECT_INVALID,
70*062c5bc4SJason Schmidlapp PTE_SPIN_UNLOCKED))
71*062c5bc4SJason Schmidlapp {
72*062c5bc4SJason Schmidlapp result = EINVAL;
73*062c5bc4SJason Schmidlapp }
74*062c5bc4SJason Schmidlapp
75*062c5bc4SJason Schmidlapp if (0 == result)
76*062c5bc4SJason Schmidlapp {
77*062c5bc4SJason Schmidlapp /*
78*062c5bc4SJason Schmidlapp * We are relying on the application to ensure that all other threads
79*062c5bc4SJason Schmidlapp * have finished with the spinlock before destroying it.
80*062c5bc4SJason Schmidlapp */
81*062c5bc4SJason Schmidlapp *lock = NULL;
82*062c5bc4SJason Schmidlapp (void) free (s);
83*062c5bc4SJason Schmidlapp }
84*062c5bc4SJason Schmidlapp }
85*062c5bc4SJason Schmidlapp else
86*062c5bc4SJason Schmidlapp {
87*062c5bc4SJason Schmidlapp /*
88*062c5bc4SJason Schmidlapp * See notes in pte_spinlock_check_need_init() above also.
89*062c5bc4SJason Schmidlapp */
90*062c5bc4SJason Schmidlapp
91*062c5bc4SJason Schmidlapp pte_osMutexLock (pte_spinlock_test_init_lock);
92*062c5bc4SJason Schmidlapp
93*062c5bc4SJason Schmidlapp /*
94*062c5bc4SJason Schmidlapp * Check again.
95*062c5bc4SJason Schmidlapp */
96*062c5bc4SJason Schmidlapp if (*lock == PTHREAD_SPINLOCK_INITIALIZER)
97*062c5bc4SJason Schmidlapp {
98*062c5bc4SJason Schmidlapp /*
99*062c5bc4SJason Schmidlapp * This is all we need to do to destroy a statically
100*062c5bc4SJason Schmidlapp * initialised spinlock that has not yet been used (initialised).
101*062c5bc4SJason Schmidlapp * If we get to here, another thread
102*062c5bc4SJason Schmidlapp * waiting to initialise this mutex will get an EINVAL.
103*062c5bc4SJason Schmidlapp */
104*062c5bc4SJason Schmidlapp *lock = NULL;
105*062c5bc4SJason Schmidlapp }
106*062c5bc4SJason Schmidlapp else
107*062c5bc4SJason Schmidlapp {
108*062c5bc4SJason Schmidlapp /*
109*062c5bc4SJason Schmidlapp * The spinlock has been initialised while we were waiting
110*062c5bc4SJason Schmidlapp * so assume it's in use.
111*062c5bc4SJason Schmidlapp */
112*062c5bc4SJason Schmidlapp result = EBUSY;
113*062c5bc4SJason Schmidlapp }
114*062c5bc4SJason Schmidlapp
115*062c5bc4SJason Schmidlapp pte_osMutexUnlock(pte_spinlock_test_init_lock);
116*062c5bc4SJason Schmidlapp
117*062c5bc4SJason Schmidlapp }
118*062c5bc4SJason Schmidlapp
119*062c5bc4SJason Schmidlapp return (result);
120*062c5bc4SJason Schmidlapp }
121