| 1 | /* Copyright (C) 2006-2022 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | /* We define a special synchronization primitive for AIO. POSIX |
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| 19 | conditional variables would be ideal but the pthread_cond_*wait |
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| 20 | operations do not return on EINTR. This is a requirement for |
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| 21 | correct aio_suspend and lio_listio implementations. */ |
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| 22 | |
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| 23 | #include <assert.h> |
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| 24 | #include <pthreadP.h> |
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| 25 | #include <futex-internal.h> |
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| 26 | |
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| 27 | #define DONT_NEED_AIO_MISC_COND 1 |
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| 28 | |
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| 29 | #define AIO_MISC_NOTIFY(waitlist) \ |
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| 30 | do { \ |
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| 31 | if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \ |
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| 32 | futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \ |
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| 33 | } while (0) |
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| 34 | |
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| 35 | #define AIO_MISC_WAIT(result, futex, timeout, cancel) \ |
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| 36 | do { \ |
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| 37 | volatile unsigned int *futexaddr = &futex; \ |
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| 38 | unsigned int oldval = futex; \ |
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| 39 | \ |
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| 40 | if (oldval != 0) \ |
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| 41 | { \ |
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| 42 | __pthread_mutex_unlock (&__aio_requests_mutex); \ |
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| 43 | \ |
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| 44 | int status; \ |
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| 45 | do \ |
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| 46 | { \ |
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| 47 | if (cancel) \ |
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| 48 | status = __futex_abstimed_wait_cancelable64 ( \ |
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| 49 | (unsigned int *) futexaddr, oldval, CLOCK_MONOTONIC, timeout, \ |
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| 50 | FUTEX_PRIVATE); \ |
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| 51 | else \ |
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| 52 | status = __futex_abstimed_wait64 ((unsigned int *) futexaddr, \ |
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| 53 | oldval, CLOCK_REALTIME, timeout, FUTEX_PRIVATE); \ |
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| 54 | if (status != EAGAIN) \ |
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| 55 | break; \ |
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| 56 | \ |
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| 57 | oldval = *futexaddr; \ |
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| 58 | } \ |
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| 59 | while (oldval != 0); \ |
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| 60 | \ |
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| 61 | if (status == EINTR) \ |
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| 62 | result = EINTR; \ |
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| 63 | else if (status == ETIMEDOUT) \ |
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| 64 | result = EAGAIN; \ |
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| 65 | else if (status == EOVERFLOW) \ |
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| 66 | result = EOVERFLOW; \ |
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| 67 | else \ |
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| 68 | assert (status == 0 || status == EAGAIN); \ |
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| 69 | \ |
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| 70 | __pthread_mutex_lock (&__aio_requests_mutex); \ |
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| 71 | } \ |
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| 72 | } while (0) |
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| 73 | |
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| 74 | #include_next <aio_misc.h> |
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| 75 | |
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