This takes the eventfd emulation code from the main loop. When the
EventNotifier is used for the main loop too, we need this compatibility
code.
Without CONFIG_EVENTFD, event_notifier_get_fd is only usable for the
"read" side of the notifier, for example to set a select() handler.
Reviewed-by: Anthony Liguori <anth...@codemonkey.ws>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
event_notifier.c | 83 +++++++++++++++++++++++++++++++++++++++++++++-----------
event_notifier.h | 3 +-
2 file modificati, 69 inserzioni(+), 17 rimozioni(-)
diff --git a/event_notifier.c b/event_notifier.c
index 2c207e1..88c114b 100644
--- a/event_notifier.c
+++ b/event_notifier.c
@@ -20,48 +20,99 @@
void event_notifier_init_fd(EventNotifier *e, int fd)
{
- e->fd = fd;
+ e->rfd = fd;
+ e->wfd = fd;
}
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) {
+ goto fail;
+ }
+ ret = fcntl_setfl(fds[1], O_NONBLOCK);
+ if (ret < 0) {
+ 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;
+ }
+ 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 f0ec2f2..f04d12d 100644
--- a/event_notifier.h
+++ b/event_notifier.h
@@ -16,7 +16,8 @@
#include "qemu-common.h"
struct EventNotifier {
- int fd;
+ int rfd;
+ int wfd;
};
typedef void EventNotifierHandler(EventNotifier *);
--
1.7.12
