On Tue, Sep 25, 2012 at 02:55:48PM +0200, Paolo Bonzini wrote:
> int event_notifier_init(EventNotifier *e, int active)
> {
> + int fds[2];
> + int ret;
> +
> #ifdef CONFIG_EVENTFD
> - int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC);
> - if (fd < 0)
> - return -errno;
> - e->fd = fd;
> - return 0;
> + ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
> #else
> - return -ENOSYS;
> + ret = -1;
> + errno = ENOSYS;
> #endif
> + if (ret >= 0) {
> + e->rfd = e->wfd = ret;
> + } else {
> + if (errno != ENOSYS) {
> + return -errno;
> + }
> + if (qemu_pipe(fds) < 0) {
> + return -errno;
> + }
> + ret = fcntl_setfl(fds[0], O_NONBLOCK);
> + if (ret < 0) {
ret = -errno;
> + goto fail;
> + }
> + ret = fcntl_setfl(fds[1], O_NONBLOCK);
> + if (ret < 0) {
ret = -errno;
> + goto fail;
> + }
> + e->rfd = fds[0];
> + e->wfd = fds[1];
> + }
> + if (active) {
> + event_notifier_set(e);
> + }
> + return 0;
> +
> +fail:
> + close(fds[0]);
> + close(fds[1]);
> + return ret;
> }
>
> void event_notifier_cleanup(EventNotifier *e)
> {
> - close(e->fd);
> + if (e->rfd != e->wfd) {
> + close(e->rfd);
> + }
> + close(e->wfd);
> }
>
> int event_notifier_get_fd(EventNotifier *e)
> {
> - return e->fd;
> + return e->rfd;
> }
>
> int event_notifier_set_handler(EventNotifier *e,
> EventNotifierHandler *handler)
> {
> - return qemu_set_fd_handler(e->fd, (IOHandler *)handler, NULL, e);
> + return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e);
> }
>
> int event_notifier_set(EventNotifier *e)
> {
> - uint64_t value = 1;
> - int r = write(e->fd, &value, sizeof(value));
> - return r == sizeof(value);
> + static const uint64_t value = 1;
> + ssize_t ret;
> +
> + do {
> + ret = write(e->wfd, &value, sizeof(value));
> + } while (ret < 0 && errno == EINTR);
> +
> + /* EAGAIN is fine, a read must be pending. */
> + if (ret < 0 && errno != EAGAIN) {
> + return -1;
If we're changing the return value representation, then we might as well:
return -errno;
But no caller actually checks the return value.
