From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=45440 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OHHN9-0003Mk-To for qemu-devel@nongnu.org; Wed, 26 May 2010 10:14:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OHHIt-00045j-7c for qemu-devel@nongnu.org; Wed, 26 May 2010 10:09:52 -0400 Received: from mail-ww0-f45.google.com ([74.125.82.45]:39026) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OHHIt-00044Y-2v for qemu-devel@nongnu.org; Wed, 26 May 2010 10:09:51 -0400 Received: by mail-ww0-f45.google.com with SMTP id 39so860125wwb.4 for ; Wed, 26 May 2010 07:09:50 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Wed, 26 May 2010 16:09:33 +0200 Message-Id: <1274882978-9875-4-git-send-email-pbonzini@redhat.com> In-Reply-To: <1274882978-9875-1-git-send-email-pbonzini@redhat.com> References: <1274882978-9875-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 3/8] remove event_notifier_test List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org This is broken; since the eventfd is used in nonblocking mode there is a race between reading and writing. Signed-off-by: Paolo Bonzini --- event_notifier.c | 15 --------------- event_notifier.h | 1 - 2 files changed, 0 insertions(+), 16 deletions(-) diff --git a/event_notifier.c b/event_notifier.c index 3f50568..0f7b8da 100644 --- a/event_notifier.c +++ b/event_notifier.c @@ -51,18 +51,3 @@ int event_notifier_test_and_clear(EventNotifier *e) int r = read(e->fd, &value, sizeof(value)); return r == sizeof(value); } - -int event_notifier_test(EventNotifier *e) -{ - uint64_t value; - int r = read(e->fd, &value, sizeof(value)); - if (r == sizeof(value)) { - /* restore previous value. */ - int s = write(e->fd, &value, sizeof(value)); - /* never blocks because we use EFD_SEMAPHORE. - * If we didn't we'd get EAGAIN on overflow - * and we'd have to write code to ignore it. */ - assert(s == sizeof(value)); - } - return r == sizeof(value); -} diff --git a/event_notifier.h b/event_notifier.h index 8d5735f..714d690 100644 --- a/event_notifier.h +++ b/event_notifier.h @@ -12,6 +12,5 @@ void event_notifier_cleanup(EventNotifier *); int event_notifier_get_fd(EventNotifier *); int event_notifier_set(EventNotifier *); int event_notifier_test_and_clear(EventNotifier *); -int event_notifier_test(EventNotifier *); #endif -- 1.6.6.1