Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> --- event_notifier.c | 69 +++++++++++++++++++++++++++++++++++++++--------------- event_notifier.h | 3 +- 2 files changed, 52 insertions(+), 20 deletions(-)
diff --git a/event_notifier.c b/event_notifier.c index 066adb9..a33f3c5 100644 --- a/event_notifier.c +++ b/event_notifier.c @@ -10,51 +10,82 @@ * the COPYING file in the top-level directory. */ +#include "qemu-common.h" #include "event_notifier.h" #include "qemu-char.h" -#ifdef CONFIG_EVENTFD -#include <sys/eventfd.h> -#endif int event_notifier_init(EventNotifier *e, int active) { -#ifdef CONFIG_EVENTFD - int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC); - if (fd < 0) + int fds[2]; + int err; + if (qemu_eventfd (fds) < 0) return -errno; - e->fd = fd; + + err = fcntl_setfl(fds[0], O_NONBLOCK); + if (err < 0) + goto fail; + + err = fcntl_setfl(fds[1], O_NONBLOCK); + if (err < 0) + goto fail; + + e->rfd = fds[0]; + e->wfd = fds[1]; + if (active) + event_notifier_set(e); return 0; -#else - return -ENOSYS; -#endif + +fail: + close(fds[0]); + close(fds[1]); + return err; } void event_notifier_cleanup(EventNotifier *e) { - close(e->fd); + close(e->rfd); + close(e->wfd); } int event_notifier_get_fd(EventNotifier *e) { - return e->fd; + return e->wfd; } 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; + } + return 0; } int event_notifier_test_and_clear(EventNotifier *e) { - uint64_t value; - int r = read(e->fd, &value, sizeof(value)); - return r == sizeof(value); + int value; + ssize_t len; + char buffer[512]; + + /* Drain the notify pipe. For eventfd, only 8 bytes will be read. */ + value = 0; + do { + len = read(e->rfd, buffer, sizeof(buffer)); + value |= (len > 0); + } while ((len == -1 && errno == EINTR) || len == sizeof(buffer)); + + return value; } diff --git a/event_notifier.h b/event_notifier.h index f6ec9ef..ff9d6f2 100644 --- a/event_notifier.h +++ b/event_notifier.h @@ -4,7 +4,8 @@ #include "qemu-common.h" struct EventNotifier { - int fd; + int rfd; + int wfd; }; typedef void EventNotifierHandler(EventNotifier *); -- 1.6.6.1