static void restart_coroutine(void *opaque)
{
Coroutine *co = opaque;
DPRINTF("co=%p", co);
aio_co_wake(co);
}
static void qio_channel_restart_write(void *opaque)
{
QIOChannel *ioc = opaque;
Coroutine *co = ioc->write_coroutine;
ioc->write_coroutine = NULL;
qio_channel_set_aio_fd_handlers(ioc);
aio_co_wake(co);
}
static void nbd_recv_coroutines_enter_all(NBDClientSession *s)
{
int i;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (s->recv_coroutine[i]) {
aio_co_wake(s->recv_coroutine[i]);
}
}
}
static void nbd_recv_coroutines_wake_all(NBDClientSession *s)
{
int i;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
NBDClientRequest *req = &s->requests[i];
if (req->coroutine && req->receiving) {
aio_co_wake(req->coroutine);
}
}
}
static void nbd_coroutine_end(BlockDriverState *bs,
NBDRequest *request)
{
NBDClientSession *s = nbd_get_client_session(bs);
int i = HANDLE_TO_INDEX(s, request->handle);
s->recv_coroutine[i] = NULL;
s->in_flight--;
qemu_co_queue_next(&s->free_sema);
/* Kick the read_reply_co to get the next reply. */
if (s->read_reply_co) {
aio_co_wake(s->read_reply_co);
}
}
static coroutine_fn void nbd_read_reply_entry(void *opaque)
{
NBDClientSession *s = opaque;
uint64_t i;
int ret = 0;
Error *local_err = NULL;
while (!s->quit) {
assert(s->reply.handle == 0);
ret = nbd_receive_reply(s->ioc, &s->reply, &local_err);
if (ret < 0) {
error_report_err(local_err);
}
if (ret <= 0) {
break;
}
/* There's no need for a mutex on the receive side, because the
* handler acts as a synchronization point and ensures that only
* one coroutine is called until the reply finishes.
*/
i = HANDLE_TO_INDEX(s, s->reply.handle);
if (i >= MAX_NBD_REQUESTS ||
!s->requests[i].coroutine ||
!s->requests[i].receiving) {
break;
}
/* We're woken up again by the request itself. Note that there
* is no race between yielding and reentering read_reply_co. This
* is because:
*
* - if the request runs on the same AioContext, it is only
* entered after we yield
*
* - if the request runs on a different AioContext, reentering
* read_reply_co happens through a bottom half, which can only
* run after we yield.
*/
aio_co_wake(s->requests[i].coroutine);
qemu_coroutine_yield();
}
s->quit = true;
nbd_recv_coroutines_wake_all(s);
s->read_reply_co = NULL;
}
static void nbd_co_receive_reply(NBDClientSession *s,
NBDRequest *request,
NBDReply *reply,
QEMUIOVector *qiov)
{
int i = HANDLE_TO_INDEX(s, request->handle);
/* Wait until we're woken up by nbd_read_reply_entry. */
s->requests[i].receiving = true;
qemu_coroutine_yield();
s->requests[i].receiving = false;
*reply = s->reply;
if (reply->handle != request->handle || !s->ioc || s->quit) {
reply->error = EIO;
} else {
if (qiov && reply->error == 0) {
assert(request->len == iov_size(qiov->iov, qiov->niov));
if (qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov,
NULL) < 0) {
reply->error = EIO;
s->quit = true;
}
}
/* Tell the read handler to read another header. */
s->reply.handle = 0;
}
s->requests[i].coroutine = NULL;
/* Kick the read_reply_co to get the next reply. */
if (s->read_reply_co) {
aio_co_wake(s->read_reply_co);
}
qemu_co_mutex_lock(&s->send_mutex);
s->in_flight--;
qemu_co_queue_next(&s->free_sema);
qemu_co_mutex_unlock(&s->send_mutex);
}
