1 /* Copyright (C) 2006-2024 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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/>. */
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. */
26 #include <futex-internal.h>
28 #define DONT_NEED_GAI_MISC_COND 1
30 #define GAI_MISC_NOTIFY(waitlist) \
32 if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \
33 futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \
36 #define GAI_MISC_WAIT(result, futex, timeout, cancel) \
38 volatile unsigned int *futexaddr = &futex; \
39 unsigned int oldval = futex; \
43 __pthread_mutex_unlock (&__gai_requests_mutex); \
49 status = __futex_abstimed_wait_cancelable64 ( \
50 (unsigned int *) futexaddr, oldval, CLOCK_MONOTONIC, timeout, \
53 status = __futex_abstimed_wait64 ((unsigned int *) futexaddr, \
54 oldval, CLOCK_REALTIME, timeout, FUTEX_PRIVATE); \
55 if (status != EAGAIN) \
58 oldval = *futexaddr; \
60 while (oldval != 0); \
62 if (status == EINTR) \
64 else if (status == ETIMEDOUT) \
66 else if (status == EOVERFLOW) \
69 assert (status == 0 || status == EAGAIN); \
71 __pthread_mutex_lock (&__gai_requests_mutex); \
76 #define gai_start_notify_thread __gai_start_notify_thread
77 #define gai_create_helper_thread __gai_create_helper_thread
80 __gai_start_notify_thread (void)
84 (void) __pthread_sigmask (SIG_SETMASK
, &ss
, NULL
);
88 __gai_create_helper_thread (pthread_t
*threadp
, void *(*tf
) (void *),
93 /* Make sure the thread is created detached. */
94 __pthread_attr_init (&attr
);
95 __pthread_attr_setdetachstate (&attr
, PTHREAD_CREATE_DETACHED
);
97 /* The helper thread needs only very little resources. */
98 (void) __pthread_attr_setstacksize (&attr
,
99 __pthread_get_minstack (&attr
)
100 + 4 * PTHREAD_STACK_MIN
);
102 /* Block all signals in the helper thread. To do this thoroughly we
103 temporarily have to block all signals here. */
107 (void) __pthread_sigmask (SIG_SETMASK
, &ss
, &oss
);
109 int ret
= __pthread_create (threadp
, &attr
, tf
, arg
);
111 /* Restore the signal mask. */
112 (void) __pthread_sigmask (SIG_SETMASK
, &oss
, NULL
);
114 (void) __pthread_attr_destroy (&attr
);
118 #include_next <gai_misc.h>