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/*
* QEMU coroutine sleep
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu/coroutine_int.h"
#include "qemu/timer.h"
#include "block/aio.h"
static const char *qemu_co_sleep_ns__scheduled = "qemu_co_sleep_ns";
void qemu_co_sleep_wake(QemuCoSleep *w)
{
Coroutine *co;
co = w->to_wake;
w->to_wake = NULL;
if (co) {
/* Write of schedule protected by barrier write in aio_co_schedule */
const char *scheduled = qatomic_cmpxchg(&co->scheduled,
qemu_co_sleep_ns__scheduled, NULL);
assert(scheduled == qemu_co_sleep_ns__scheduled);
aio_co_wake(co);
}
}
static void co_sleep_cb(void *opaque)
{
QemuCoSleep *w = opaque;
qemu_co_sleep_wake(w);
}
void coroutine_fn qemu_co_sleep(QemuCoSleep *w)
{
Coroutine *co = qemu_coroutine_self();
const char *scheduled = qatomic_cmpxchg(&co->scheduled, NULL,
qemu_co_sleep_ns__scheduled);
if (scheduled) {
fprintf(stderr,
"%s: Co-routine was already scheduled in '%s'\n",
__func__, scheduled);
abort();
}
w->to_wake = co;
qemu_coroutine_yield();
/* w->to_wake is cleared before resuming this coroutine. */
assert(w->to_wake == NULL);
}
void coroutine_fn qemu_co_sleep_ns_wakeable(QemuCoSleep *w,
QEMUClockType type, int64_t ns)
{
AioContext *ctx = qemu_get_current_aio_context();
QEMUTimer ts;
aio_timer_init(ctx, &ts, type, SCALE_NS, co_sleep_cb, w);
timer_mod(&ts, qemu_clock_get_ns(type) + ns);
/*
* The timer will fire in the current AiOContext, so the callback
* must happen after qemu_co_sleep yields and there is no race
* between timer_mod and qemu_co_sleep.
*/
qemu_co_sleep(w);
timer_del(&ts);
}
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