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[Qemu-devel] [PATCH 6/8] enable event_notifier to use pipes
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 6/8] enable event_notifier to use pipes |
Date: |
Wed, 26 May 2010 16:09:36 +0200 |
Signed-off-by: Paolo Bonzini <address@hidden>
---
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
- [Qemu-devel] [PATCH 0/8] Make event_notifier more useful and more used, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 6/8] enable event_notifier to use pipes,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 7/8] add Win32 implementation of event notifiers, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 1/8] move event_notifier into the main directory, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 3/8] remove event_notifier_test, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 5/8] add and use event_notifier_set_handler, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 4/8] add and use virtqueue_from_guest_notifier, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 8/8] change ioevent to use event notifiers, Paolo Bonzini, 2010/05/26
- [Qemu-devel] [PATCH 2/8] add event_notifier_set, Paolo Bonzini, 2010/05/26
- [Qemu-devel] Re: [PATCH 0/8] Make event_notifier more useful and more used, Michael S. Tsirkin, 2010/05/27