From a3462c656128e7b900ccc5d436f9e858d07de264 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 9 Jul 2014 11:53:08 +0200
Subject: [PATCH] AioContext: introduce aio_prepare
This will be used to implement socket polling on Windows.
On Windows, select() and g_poll() are completely different;
sockets are polled with select() before calling g_poll,
and the g_poll must be nonblocking if select() says a
socket is ready.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
aio-posix.c | 5 +++++
aio-win32.c | 5 +++++
async.c | 5 +++++
include/block/aio.h | 9 ++++++++-
4 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/aio-posix.c b/aio-posix.c
index 0936b4ff9d5..d3ac06e238b 100644
--- a/aio-posix.c
+++ b/aio-posix.c
@@ -100,6 +100,11 @@ void aio_set_event_notifier(AioContext *ctx,
(IOHandler *)io_read, NULL, notifier);
}
+bool aio_prepare(AioContext *ctx)
+{
+ return false;
+}
+
bool aio_pending(AioContext *ctx)
{
AioHandler *node;
diff --git a/aio-win32.c b/aio-win32.c
index fd526864be7..45422704a46 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -76,6 +76,11 @@ void aio_set_event_notifier(AioContext *ctx,
aio_notify(ctx);
}
+bool aio_prepare(AioContext *ctx)
+{
+ return false;
+}
+
bool aio_pending(AioContext *ctx)
{
AioHandler *node;
diff --git a/async.c b/async.c
index 293a52a0a73..a99e7f639a4 100644
--- a/async.c
+++ b/async.c
@@ -188,6 +188,11 @@ aio_ctx_prepare(GSource *source, gint *timeout)
/* We assume there is no timeout already supplied */
*timeout = qemu_timeout_ns_to_ms(aio_compute_timeout(ctx));
+
+ if (aio_prepare(ctx)) {
+ *timeout = 0;
+ }
+
return *timeout == 0;
}
diff --git a/include/block/aio.h b/include/block/aio.h
index 7ba3e9675b8..ef4197b8619 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -205,7 +205,14 @@ void qemu_bh_cancel(QEMUBH *bh);
void qemu_bh_delete(QEMUBH *bh);
/* Return whether there are any pending callbacks from the GSource
- * attached to the AioContext.
+ * attached to the AioContext, before g_poll is invoked.
+ *
+ * This is used internally in the implementation of the GSource.
+ */
+bool aio_prepare(AioContext *ctx);
+
+/* Return whether there are any pending callbacks from the GSource
+ * attached to the AioContext, after g_poll is invoked.
*
* This is used internally in the implementation of the GSource.
*/
--
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