static void qemu_laio_completion_cb(void *opaque)
{
struct qemu_laio_state *s = opaque;
while (1) {
struct io_event events[MAX_EVENTS];
uint64_t val;
ssize_t ret;
struct timespec ts = { 0 };
int nevents, i;
do {
ret = read(s->efd, &val, sizeof(val));
} while (ret == -1 && errno == EINTR);
if (ret == -1 && errno == EAGAIN)
break;
if (ret != 8)
break;
do {
nevents = io_getevents(s->ctx, val, MAX_EVENTS, events, &ts);
} while (nevents == -EINTR);
for (i = 0; i < nevents; i++) {
struct iocb *iocb = events[i].obj;
struct qemu_laiocb *laiocb =
container_of(iocb, struct qemu_laiocb, iocb);
laiocb->ret = io_event_ret(&events[i]);
qemu_laio_process_completion(s, laiocb);
}
}
}
/* The completion BH fetches completed I/O requests and invokes their
* callbacks.
*
* The function is somewhat tricky because it supports nested event loops, for
* example when a request callback invokes aio_poll(). In order to do this,
* the completion events array and index are kept in qemu_laio_state. The BH
* reschedules itself as long as there are completions pending so it will
* either be called again in a nested event loop or will be called after all
* events have been completed. When there are no events left to complete, the
* BH returns without rescheduling.
*/
static void qemu_laio_completion_bh(void *opaque)
{
struct qemu_laio_state *s = opaque;
/* Fetch more completion events when empty */
if (s->event_idx == s->event_max) {
do {
struct timespec ts = { 0 };
s->event_max = io_getevents(s->ctx, MAX_EVENTS, MAX_EVENTS,
s->events, &ts);
} while (s->event_max == -EINTR);
s->event_idx = 0;
if (s->event_max <= 0) {
s->event_max = 0;
return; /* no more events */
}
}
/* Reschedule so nested event loops see currently pending completions */
qemu_bh_schedule(s->completion_bh);
/* Process completion events */
while (s->event_idx < s->event_max) {
struct iocb *iocb = s->events[s->event_idx].obj;
struct qemu_laiocb *laiocb =
container_of(iocb, struct qemu_laiocb, iocb);
laiocb->ret = io_event_ret(&s->events[s->event_idx]);
s->event_idx++;
qemu_laio_process_completion(s, laiocb);
}
}
static void qemu_laio_completion_cb(EventNotifier *e)
{
struct qemu_laio_state *s = container_of(e, struct qemu_laio_state, e);
while (event_notifier_test_and_clear(&s->e)) {
struct io_event events[MAX_EVENTS];
struct timespec ts = { 0 };
int nevents, i;
do {
nevents = io_getevents(s->ctx, MAX_EVENTS, MAX_EVENTS, events, &ts);
} while (nevents == -EINTR);
for (i = 0; i < nevents; i++) {
struct iocb *iocb = events[i].obj;
struct qemu_laiocb *laiocb =
container_of(iocb, struct qemu_laiocb, iocb);
laiocb->ret = io_event_ret(&events[i]);
qemu_laio_process_completion(s, laiocb);
}
}
}
