On Wed, Jul 9, 2014 at 5:53 PM, Paolo Bonzini <pbonz...@redhat.com> wrote:
> Uses the same select/WSAEventSelect scheme as main-loop.c.
> WSAEventSelect() is edge-triggered, so it cannot be used
> directly, but it is still used as a way to exit from a
> blocking g_poll().
>
> Before g_poll() is called, we poll sockets with a non-blocking
> select() to achieve the level-triggered semantics we require:
> if a socket is ready, the g_poll() is made non-blocking too.
>
> Based on a patch from Or Goshen.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> aio-win32.c | 150
> ++++++++++++++++++++++++++++++++++++++++++++++++++--
> block/Makefile.objs | 2 -
> include/block/aio.h | 2 -
> 3 files changed, 145 insertions(+), 9 deletions(-)
>
> diff --git a/aio-win32.c b/aio-win32.c
> index 4542270..61e3d2d 100644
> --- a/aio-win32.c
> +++ b/aio-win32.c
> @@ -183,6 +318,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
>
> /* wait until next event */
> while (count > 0) {
> + HANDLE event;
> int ret;
>
> timeout = blocking
> @@ -196,13 +332,17 @@ bool aio_poll(AioContext *ctx, bool blocking)
> first = false;
>
> /* if we have any signaled events, dispatch event */
> - if ((DWORD) (ret - WAIT_OBJECT_0) >= count) {
> + event = NULL;
> + if ((DWORD) (ret - WAIT_OBJECT_0) < count) {
> + event = events[ret - WAIT_OBJECT_0];
> + } else if (!have_select_revents) {
when (ret - WAIT_OBJECT_0) >= count and have_select_revents is true,
the following events[ret - WAIT_OBJECT_0] will be overflowed.
> break;
> }
>
> + have_select_revents = false;
> blocking = false;
>
> - progress |= aio_dispatch_handlers(ctx, events[ret - WAIT_OBJECT_0]);
> + progress |= aio_dispatch_handlers(ctx, event);
>
> /* Try again, but only call each handler once. */
> events[ret - WAIT_OBJECT_0] = events[--count];
