1/* Copyright (C) 2006-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18/* We define a special synchronization primitive for AIO. POSIX
19 conditional variables would be ideal but the pthread_cond_*wait
20 operations do not return on EINTR. This is a requirement for
21 correct aio_suspend and lio_listio implementations. */
22
23#include <assert.h>
24#include <nptl/pthreadP.h>
25#include <futex-internal.h>
26
27#define DONT_NEED_AIO_MISC_COND 1
28
29#define AIO_MISC_NOTIFY(waitlist) \
30 do { \
31 if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \
32 futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \
33 } while (0)
34
35#define AIO_MISC_WAIT(result, futex, timeout, cancel) \
36 do { \
37 volatile unsigned int *futexaddr = &futex; \
38 unsigned int oldval = futex; \
39 \
40 if (oldval != 0) \
41 { \
42 pthread_mutex_unlock (&__aio_requests_mutex); \
43 \
44 int status; \
45 do \
46 { \
47 if (cancel) \
48 status = futex_reltimed_wait_cancelable ( \
49 (unsigned int *) futexaddr, oldval, timeout, FUTEX_PRIVATE); \
50 else \
51 status = futex_reltimed_wait ((unsigned int *) futexaddr, \
52 oldval, timeout, FUTEX_PRIVATE); \
53 if (status != EAGAIN) \
54 break; \
55 \
56 oldval = *futexaddr; \
57 } \
58 while (oldval != 0); \
59 \
60 if (status == EINTR) \
61 result = EINTR; \
62 else if (status == ETIMEDOUT) \
63 result = EAGAIN; \
64 else \
65 assert (status == 0 || status == EAGAIN); \
66 \
67 pthread_mutex_lock (&__aio_requests_mutex); \
68 } \
69 } while (0)
70
71#include_next <aio_misc.h>
72