eaee072085
All callers of qemu_co_sleep_wake are checking whether they are passing a NULL argument inside the pointer-to-pointer: do the check in qemu_co_sleep_wake itself. As a side effect, qemu_co_sleep_wake can be called more than once and it will only wake the coroutine once; after the first time, the argument will be set to NULL via *sleep_state->user_state_pointer. However, this would not be safe unless co_sleep_cb keeps using the QemuCoSleepState* directly, so make it go through the pointer-to-pointer instead. Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20210517100548.28806-4-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
74 lines
2.1 KiB
C
74 lines
2.1 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";
|
|
|
|
struct QemuCoSleepState {
|
|
Coroutine *co;
|
|
QEMUTimer ts;
|
|
QemuCoSleepState **user_state_pointer;
|
|
};
|
|
|
|
void qemu_co_sleep_wake(QemuCoSleepState *sleep_state)
|
|
{
|
|
if (sleep_state) {
|
|
/* Write of schedule protected by barrier write in aio_co_schedule */
|
|
const char *scheduled = qatomic_cmpxchg(&sleep_state->co->scheduled,
|
|
qemu_co_sleep_ns__scheduled, NULL);
|
|
|
|
assert(scheduled == qemu_co_sleep_ns__scheduled);
|
|
*sleep_state->user_state_pointer = NULL;
|
|
timer_del(&sleep_state->ts);
|
|
aio_co_wake(sleep_state->co);
|
|
}
|
|
}
|
|
|
|
static void co_sleep_cb(void *opaque)
|
|
{
|
|
QemuCoSleepState **sleep_state = opaque;
|
|
qemu_co_sleep_wake(*sleep_state);
|
|
}
|
|
|
|
void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns,
|
|
QemuCoSleepState **sleep_state)
|
|
{
|
|
AioContext *ctx = qemu_get_current_aio_context();
|
|
QemuCoSleepState state = {
|
|
.co = qemu_coroutine_self(),
|
|
.user_state_pointer = sleep_state,
|
|
};
|
|
|
|
const char *scheduled = qatomic_cmpxchg(&state.co->scheduled, NULL,
|
|
qemu_co_sleep_ns__scheduled);
|
|
if (scheduled) {
|
|
fprintf(stderr,
|
|
"%s: Co-routine was already scheduled in '%s'\n",
|
|
__func__, scheduled);
|
|
abort();
|
|
}
|
|
|
|
aio_timer_init(ctx, &state.ts, type, SCALE_NS, co_sleep_cb, sleep_state);
|
|
*sleep_state = &state;
|
|
timer_mod(&state.ts, qemu_clock_get_ns(type) + ns);
|
|
qemu_coroutine_yield();
|
|
|
|
/* qemu_co_sleep_wake clears *sleep_state before resuming this coroutine. */
|
|
assert(*sleep_state == NULL);
|
|
}
|