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authorPaolo Bonzini <pbonzini@redhat.com>2012-11-23 15:59:43 +0100
committerAnthony Liguori <aliguori@us.ibm.com>2012-11-26 09:37:06 -0600
commitb022b4a44abda9b6f89777b07e538be6f8f7aacb (patch)
tree930770a31ba76f6071b6f2d79423e2aa76fe2173 /aio-win32.c
parent21022c92dc5095324ceb3effc068b5ff81642125 (diff)
aio: avoid livelock behavior for Win32
The repeated calls to WaitForMultipleObjects may cause a livelock in aio_poll, where no progress is made on bottom halves. This patch matches the behavior of the POSIX code. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'aio-win32.c')
-rw-r--r--aio-win32.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/aio-win32.c b/aio-win32.c
index a84eb71246..cec4646635 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -173,7 +173,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
}
/* wait until next event */
- for (;;) {
+ while (count > 0) {
int timeout = blocking ? INFINITE : 0;
int ret = WaitForMultipleObjects(count, events, FALSE, timeout);
@@ -209,6 +209,9 @@ bool aio_poll(AioContext *ctx, bool blocking)
g_free(tmp);
}
}
+
+ /* Try again, but only call each handler once. */
+ events[ret - WAIT_OBJECT_0] = events[--count];
}
return progress;