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75 lines
2.6 KiB
C
75 lines
2.6 KiB
C
/* Copyright (C) 2006-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* We define a special synchronization primitive for AIO. POSIX
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conditional variables would be ideal but the pthread_cond_*wait
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operations do not return on EINTR. This is a requirement for
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correct aio_suspend and lio_listio implementations. */
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#include <assert.h>
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#include <nptl/pthreadP.h>
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#include <futex-internal.h>
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#define DONT_NEED_AIO_MISC_COND 1
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#define AIO_MISC_NOTIFY(waitlist) \
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do { \
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if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \
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futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \
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} while (0)
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#define AIO_MISC_WAIT(result, futex, timeout, cancel) \
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do { \
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volatile unsigned int *futexaddr = &futex; \
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unsigned int oldval = futex; \
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\
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if (oldval != 0) \
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{ \
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pthread_mutex_unlock (&__aio_requests_mutex); \
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\
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int oldtype; \
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if (cancel) \
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oldtype = LIBC_CANCEL_ASYNC (); \
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\
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int status; \
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do \
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{ \
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status = futex_reltimed_wait ((unsigned int *) futexaddr, oldval, \
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timeout, FUTEX_PRIVATE); \
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if (status != EAGAIN) \
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break; \
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\
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oldval = *futexaddr; \
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} \
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while (oldval != 0); \
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\
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if (cancel) \
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LIBC_CANCEL_RESET (oldtype); \
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\
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if (status == EINTR) \
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result = EINTR; \
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else if (status == ETIMEDOUT) \
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result = EAGAIN; \
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else \
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assert (status == 0 || status == EAGAIN); \
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\
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pthread_mutex_lock (&__aio_requests_mutex); \
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} \
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} while (0)
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#include_next <aio_misc.h>
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