Function fdset_event_dispatch

dpdk/lib/vhost/fd_man.c:215–307

* This functions runs in infinite blocking loop until there is no fd in * pfdset. It calls corresponding r/w handler if there is event on the fd. * * Before the callback is called, we set the flag to busy status; If other * thread(now rte_vhost_driver_unregister) calls fdset_del concurrently, it * will wait until the flag is reset to zero(which indicates the callback is * finished), then it

 * finished), then it could free the context after fdset_del.
 */
uint32_t
fdset_event_dispatch(void *arg)
{
	int i;
	struct pollfd *pfd;
	struct fdentry *pfdentry;
	fd_cb rcb, wcb;
	void *dat;
	int fd, numfds;
	int remove1, remove2;
	int need_shrink;
	struct fdset *pfdset = arg;
	int val;

	if (pfdset == NULL)
		return 0;

	while (1) {

		/*
		 * When poll is blocked, other threads might unregister
		 * listenfds from and register new listenfds into fdset.
		 * When poll returns, the entries for listenfds in the fdset
		 * might have been updated. It is ok if there is unwanted call
		 * for new listenfds.
		 */
		pthread_mutex_lock(&pfdset->fd_mutex);
		numfds = pfdset->num;
		pthread_mutex_unlock(&pfdset->fd_mutex);

		pthread_mutex_lock(&pfdset->fd_pooling_mutex);
		val = poll(pfdset->rwfds, numfds, 1000 /* millisecs */);
		pthread_mutex_unlock(&pfdset->fd_pooling_mutex);
		if (val < 0)
			continue;

		need_shrink = 0;
		for (i = 0; i < numfds; i++) {
			pthread_mutex_lock(&pfdset->fd_mutex);

			pfdentry = &pfdset->fd[i];
			fd = pfdentry->fd;
			pfd = &pfdset->rwfds[i];

			if (fd < 0) {
				need_shrink = 1;
				pthread_mutex_unlock(&pfdset->fd_mutex);
				continue;
			}

			if (!pfd->revents) {
				pthread_mutex_unlock(&pfdset->fd_mutex);
				continue;
			}

			remove1 = remove2 = 0;

			rcb = pfdentry->rcb;