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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [PATCH 3/8] remove event_notifier_test
Date: Wed, 26 May 2010 16:09:33 +0200	[thread overview]
Message-ID: <1274882978-9875-4-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1274882978-9875-1-git-send-email-pbonzini@redhat.com>

This is broken; since the eventfd is used in nonblocking mode there
is a race between reading and writing.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 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

  parent reply	other threads:[~2010-05-26 14:14 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-26 14:09 [Qemu-devel] [PATCH 0/8] Make event_notifier more useful and more used Paolo Bonzini
2010-05-26 14:09 ` [Qemu-devel] [PATCH 1/8] move event_notifier into the main directory Paolo Bonzini
2010-05-26 14:09 ` [Qemu-devel] [PATCH 2/8] add event_notifier_set Paolo Bonzini
2010-05-26 14:09 ` Paolo Bonzini [this message]
2010-05-26 14:09 ` [Qemu-devel] [PATCH 4/8] add and use virtqueue_from_guest_notifier Paolo Bonzini
2010-05-26 14:09 ` [Qemu-devel] [PATCH 5/8] add and use event_notifier_set_handler Paolo Bonzini
2010-05-26 14:09 ` [Qemu-devel] [PATCH 6/8] enable event_notifier to use pipes Paolo Bonzini
2010-05-26 18:19   ` Richard Henderson
2010-05-26 19:48     ` [Qemu-devel] " Paolo Bonzini
2010-05-26 14:09 ` [Qemu-devel] [PATCH 7/8] add Win32 implementation of event notifiers Paolo Bonzini
2010-05-26 14:09 ` [Qemu-devel] [PATCH 8/8] change ioevent to use " Paolo Bonzini
2010-05-27 14:21 ` [Qemu-devel] Re: [PATCH 0/8] Make event_notifier more useful and more used Michael S. Tsirkin
2010-05-27 15:37   ` Paolo Bonzini
2010-06-15 13:53 ` Paolo Bonzini

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