static void nbd_reply_ready(void *opaque) { NbdClientSession *s = opaque; uint64_t i; int ret; if (s->reply.handle == 0) { /* No reply already in flight. Fetch a header. It is possible * that another thread has done the same thing in parallel, so * the socket is not readable anymore. */ ret = nbd_receive_reply(s->sock, &s->reply); if (ret == -EAGAIN) { return; } if (ret < 0) { s->reply.handle = 0; goto fail; } } /* 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) { goto fail; } if (s->recv_coroutine[i]) { qemu_coroutine_enter(s->recv_coroutine[i], NULL); return; } fail: nbd_teardown_connection(s); }