[PATCH v2 1/2] aio: Provide Linux specific copy of aio_suspend.c
Lukasz Majewski
lukma@denx.de
Sat Nov 14 21:45:21 GMT 2020
This patch is a preparatory work, to provide 64 bit time support
to aio_suspend.c, which would avoid build breaks on the HURD (i686-gnu)
port, as it is not supporting 64 bit version of
__pthread_cond_timedwait64.
The file sysdeps/unix/sysv/linux/aio_suspend.c is the exact copy of
./sysdeps/pthread/aio_suspend.c
---
Changes for v2:
- Rephase the commit message
---
sysdeps/unix/sysv/linux/aio_suspend.c | 253 ++++++++++++++++++++++++++
1 file changed, 253 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/aio_suspend.c
diff --git a/sysdeps/unix/sysv/linux/aio_suspend.c b/sysdeps/unix/sysv/linux/aio_suspend.c
new file mode 100644
index 0000000000..ad03f13558
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aio_suspend.c
@@ -0,0 +1,253 @@
+/* Suspend until termination of a requests.
+ Copyright (C) 1997-2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+
+/* We use an UGLY hack to prevent gcc from finding us cheating. The
+ implementations of aio_suspend and aio_suspend64 are identical and so
+ we want to avoid code duplication by using aliases. But gcc sees
+ the different parameter lists and prints a warning. We define here
+ a function so that aio_suspend64 has no prototype. */
+#define aio_suspend64 XXX
+#include <aio.h>
+/* And undo the hack. */
+#undef aio_suspend64
+
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+#include <libc-lock.h>
+#include <aio_misc.h>
+
+
+struct clparam
+{
+ const struct aiocb *const *list;
+ struct waitlist *waitlist;
+ struct requestlist **requestlist;
+#ifndef DONT_NEED_AIO_MISC_COND
+ pthread_cond_t *cond;
+#endif
+ int nent;
+};
+
+
+static void
+cleanup (void *arg)
+{
+#ifdef DONT_NEED_AIO_MISC_COND
+ /* Acquire the mutex. If pthread_cond_*wait is used this would
+ happen implicitly. */
+ pthread_mutex_lock (&__aio_requests_mutex);
+#endif
+
+ const struct clparam *param = (const struct clparam *) arg;
+
+ /* Now remove the entry in the waiting list for all requests
+ which didn't terminate. */
+ int cnt = param->nent;
+ while (cnt-- > 0)
+ if (param->list[cnt] != NULL
+ && param->list[cnt]->__error_code == EINPROGRESS)
+ {
+ struct waitlist **listp;
+
+ assert (param->requestlist[cnt] != NULL);
+
+ /* There is the chance that we cannot find our entry anymore. This
+ could happen if the request terminated and restarted again. */
+ listp = ¶m->requestlist[cnt]->waiting;
+ while (*listp != NULL && *listp != ¶m->waitlist[cnt])
+ listp = &(*listp)->next;
+
+ if (*listp != NULL)
+ *listp = (*listp)->next;
+ }
+
+#ifndef DONT_NEED_AIO_MISC_COND
+ /* Release the conditional variable. */
+ (void) pthread_cond_destroy (param->cond);
+#endif
+
+ /* Release the mutex. */
+ pthread_mutex_unlock (&__aio_requests_mutex);
+}
+
+#ifdef DONT_NEED_AIO_MISC_COND
+static int
+__attribute__ ((noinline))
+do_aio_misc_wait (unsigned int *cntr, const struct timespec *timeout)
+{
+ int result = 0;
+
+ AIO_MISC_WAIT (result, *cntr, timeout, 1);
+
+ return result;
+}
+#endif
+
+int
+aio_suspend (const struct aiocb *const list[], int nent,
+ const struct timespec *timeout)
+{
+ if (__glibc_unlikely (nent < 0))
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+
+ struct waitlist waitlist[nent];
+ struct requestlist *requestlist[nent];
+#ifndef DONT_NEED_AIO_MISC_COND
+ pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+#endif
+ int cnt;
+ bool any = false;
+ int result = 0;
+ unsigned int cntr = 1;
+
+ /* Request the mutex. */
+ pthread_mutex_lock (&__aio_requests_mutex);
+
+ /* There is not yet a finished request. Signal the request that
+ we are working for it. */
+ for (cnt = 0; cnt < nent; ++cnt)
+ if (list[cnt] != NULL)
+ {
+ if (list[cnt]->__error_code == EINPROGRESS)
+ {
+ requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]);
+
+ if (requestlist[cnt] != NULL)
+ {
+#ifndef DONT_NEED_AIO_MISC_COND
+ waitlist[cnt].cond = &cond;
+#endif
+ waitlist[cnt].result = NULL;
+ waitlist[cnt].next = requestlist[cnt]->waiting;
+ waitlist[cnt].counterp = &cntr;
+ waitlist[cnt].sigevp = NULL;
+ requestlist[cnt]->waiting = &waitlist[cnt];
+ any = true;
+ }
+ else
+ /* We will never suspend. */
+ break;
+ }
+ else
+ /* We will never suspend. */
+ break;
+ }
+
+
+ /* Only if none of the entries is NULL or finished to be wait. */
+ if (cnt == nent && any)
+ {
+ struct clparam clparam =
+ {
+ .list = list,
+ .waitlist = waitlist,
+ .requestlist = requestlist,
+#ifndef DONT_NEED_AIO_MISC_COND
+ .cond = &cond,
+#endif
+ .nent = nent
+ };
+
+ pthread_cleanup_push (cleanup, &clparam);
+
+#ifdef DONT_NEED_AIO_MISC_COND
+ result = do_aio_misc_wait (&cntr, timeout);
+#else
+ if (timeout == NULL)
+ result = pthread_cond_wait (&cond, &__aio_requests_mutex);
+ else
+ {
+ /* We have to convert the relative timeout value into an
+ absolute time value with pthread_cond_timedwait expects. */
+ struct timespec now;
+ struct timespec abstime;
+
+ __clock_gettime (CLOCK_REALTIME, &now);
+ abstime.tv_nsec = timeout->tv_nsec + now.tv_nsec;
+ abstime.tv_sec = timeout->tv_sec + now.tv_sec;
+ if (abstime.tv_nsec >= 1000000000)
+ {
+ abstime.tv_nsec -= 1000000000;
+ abstime.tv_sec += 1;
+ }
+
+ result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
+ &abstime);
+ }
+#endif
+
+ pthread_cleanup_pop (0);
+ }
+
+ /* Now remove the entry in the waiting list for all requests
+ which didn't terminate. */
+ while (cnt-- > 0)
+ if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS)
+ {
+ struct waitlist **listp;
+
+ assert (requestlist[cnt] != NULL);
+
+ /* There is the chance that we cannot find our entry anymore. This
+ could happen if the request terminated and restarted again. */
+ listp = &requestlist[cnt]->waiting;
+ while (*listp != NULL && *listp != &waitlist[cnt])
+ listp = &(*listp)->next;
+
+ if (*listp != NULL)
+ *listp = (*listp)->next;
+ }
+
+#ifndef DONT_NEED_AIO_MISC_COND
+ /* Release the conditional variable. */
+ if (__glibc_unlikely (pthread_cond_destroy (&cond) != 0))
+ /* This must never happen. */
+ abort ();
+#endif
+
+ if (result != 0)
+ {
+#ifndef DONT_NEED_AIO_MISC_COND
+ /* An error occurred. Possibly it's ETIMEDOUT. We have to translate
+ the timeout error report of `pthread_cond_timedwait' to the
+ form expected from `aio_suspend'. */
+ if (result == ETIMEDOUT)
+ __set_errno (EAGAIN);
+ else
+#endif
+ __set_errno (result);
+
+ result = -1;
+ }
+
+ /* Release the mutex. */
+ pthread_mutex_unlock (&__aio_requests_mutex);
+
+ return result;
+}
+
+weak_alias (aio_suspend, aio_suspend64)
--
2.20.1
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