void qemu_co_rwlock_wrlock(CoRwlock *lock)
{
while (lock->writer || lock->reader) {
qemu_co_queue_wait(&lock->queue);
}
lock->writer = true;
}
void qemu_co_rwlock_rdlock(CoRwlock *lock)
{
while (lock->writer) {
qemu_co_queue_wait(&lock->queue);
}
lock->reader++;
}
void fdt_init_yield(FDTMachineInfo *fdti)
{
static int yield_index;
int this_yield = yield_index++;
DB_PRINT(1, "Yield #%d\n", this_yield);
qemu_co_queue_wait(fdti->cq, NULL);
DB_PRINT(1, "Unyield #%d\n", this_yield);
}
static void nbd_coroutine_start(NBDClientSession *s,
NBDRequest *request)
{
/* Poor man semaphore. The free_sema is locked when no other request
* can be accepted, and unlocked after receiving one reply. */
if (s->in_flight == MAX_NBD_REQUESTS) {
qemu_co_queue_wait(&s->free_sema, NULL);
assert(s->in_flight < MAX_NBD_REQUESTS);
}
s->in_flight++;
/* s->recv_coroutine[i] is set as soon as we get the send_lock. */
}
void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
{
Coroutine *self = qemu_coroutine_self();
trace_qemu_co_mutex_lock_entry(mutex, self);
while (mutex->locked) {
qemu_co_queue_wait(&mutex->queue);
}
mutex->locked = true;
trace_qemu_co_mutex_lock_return(mutex, self);
}
static int nbd_co_send_request(BlockDriverState *bs,
NBDRequest *request,
QEMUIOVector *qiov)
{
NBDClientSession *s = nbd_get_client_session(bs);
int rc, ret, i;
qemu_co_mutex_lock(&s->send_mutex);
while (s->in_flight == MAX_NBD_REQUESTS) {
qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
}
s->in_flight++;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (s->recv_coroutine[i] == NULL) {
s->recv_coroutine[i] = qemu_coroutine_self();
break;
}
}
g_assert(qemu_in_coroutine());
assert(i < MAX_NBD_REQUESTS);
request->handle = INDEX_TO_HANDLE(s, i);
if (!s->ioc) {
qemu_co_mutex_unlock(&s->send_mutex);
return -EPIPE;
}
if (qiov) {
qio_channel_set_cork(s->ioc, true);
rc = nbd_send_request(s->ioc, request);
if (rc >= 0) {
ret = nbd_rwv(s->ioc, qiov->iov, qiov->niov, request->len, false,
NULL);
if (ret != request->len) {
rc = -EIO;
}
}
qio_channel_set_cork(s->ioc, false);
} else {
rc = nbd_send_request(s->ioc, request);
}
qemu_co_mutex_unlock(&s->send_mutex);
return rc;
}
void coroutine_fn fsdev_co_throttle_request(FsThrottle *fst, bool is_write,
struct iovec *iov, int iovcnt)
{
if (throttle_enabled(&fst->cfg)) {
if (throttle_schedule_timer(&fst->ts, &fst->tt, is_write) ||
!qemu_co_queue_empty(&fst->throttled_reqs[is_write])) {
qemu_co_queue_wait(&fst->throttled_reqs[is_write], NULL);
}
throttle_account(&fst->ts, is_write, iov_size(iov, iovcnt));
if (!qemu_co_queue_empty(&fst->throttled_reqs[is_write]) &&
!throttle_schedule_timer(&fst->ts, &fst->tt, is_write)) {
qemu_co_queue_next(&fst->throttled_reqs[is_write]);
}
}
}
static int nbd_co_send_request(BlockDriverState *bs,
NBDRequest *request,
QEMUIOVector *qiov)
{
NBDClientSession *s = nbd_get_client_session(bs);
int rc, i;
qemu_co_mutex_lock(&s->send_mutex);
while (s->in_flight == MAX_NBD_REQUESTS) {
qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
}
s->in_flight++;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (s->requests[i].coroutine == NULL) {
break;
}
}
g_assert(qemu_in_coroutine());
assert(i < MAX_NBD_REQUESTS);
s->requests[i].coroutine = qemu_coroutine_self();
s->requests[i].receiving = false;
request->handle = INDEX_TO_HANDLE(s, i);
if (s->quit) {
rc = -EIO;
goto err;
}
if (!s->ioc) {
rc = -EPIPE;
goto err;
}
if (qiov) {
qio_channel_set_cork(s->ioc, true);
rc = nbd_send_request(s->ioc, request);
if (rc >= 0 && !s->quit) {
assert(request->len == iov_size(qiov->iov, qiov->niov));
if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov,
NULL) < 0) {
rc = -EIO;
}
}
qio_channel_set_cork(s->ioc, false);
} else {
rc = nbd_send_request(s->ioc, request);
}
err:
if (rc < 0) {
s->quit = true;
s->requests[i].coroutine = NULL;
s->in_flight--;
qemu_co_queue_next(&s->free_sema);
}
qemu_co_mutex_unlock(&s->send_mutex);
return rc;
}
