qemu/util/qemu-coroutine-sleep.c
Paolo Bonzini 29a6ea24eb coroutine-sleep: replace QemuCoSleepState pointer with struct in the API
Right now, users of qemu_co_sleep_ns_wakeable are simply passing
a pointer to QemuCoSleepState by reference to the function.  But
QemuCoSleepState really is just a Coroutine*; making the
content of the struct public is just as efficient and lets us
skip the user_state_pointer indirection.

Since the usage is changed, take the occasion to rename the
struct to QemuCoSleep.

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20210517100548.28806-6-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-05-21 18:22:33 +01:00

68 lines
1.8 KiB
C

/*
* 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.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_ns_wakeable(QemuCoSleep *w,
QEMUClockType type, int64_t ns)
{
Coroutine *co = qemu_coroutine_self();
AioContext *ctx = qemu_get_current_aio_context();
QEMUTimer ts;
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;
aio_timer_init(ctx, &ts, type, SCALE_NS, co_sleep_cb, w),
timer_mod(&ts, qemu_clock_get_ns(type) + ns);
qemu_coroutine_yield();
timer_del(&ts);
/* w->to_wake is cleared before resuming this coroutine. */
assert(w->to_wake == NULL);
}