Hi

On Wed, Aug 24, 2022 at 12:52 PM Bin Meng <bmeng...@gmail.com> wrote:

> From: Bin Meng <bin.m...@windriver.com>
>
> The maximum number of wait objects for win32 should be
> MAXIMUM_WAIT_OBJECTS, not MAXIMUM_WAIT_OBJECTS + 1.
>
> Signed-off-by: Bin Meng <bin.m...@windriver.com>
> ---
>
> Changes in v3:
> - move the check of adding the same HANDLE twice to a separete patch
>
> Changes in v2:
> - fix the logic in qemu_add_wait_object() to avoid adding
>   the same HANDLE twice
>
>  util/main-loop.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/util/main-loop.c b/util/main-loop.c
> index f00a25451b..cb018dc33c 100644
> --- a/util/main-loop.c
> +++ b/util/main-loop.c
> @@ -363,10 +363,10 @@ void qemu_del_polling_cb(PollingFunc *func, void
> *opaque)
>  /* Wait objects support */
>  typedef struct WaitObjects {
>      int num;
> -    int revents[MAXIMUM_WAIT_OBJECTS + 1];
> -    HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
> -    WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
> -    void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
> +    int revents[MAXIMUM_WAIT_OBJECTS];
> +    HANDLE events[MAXIMUM_WAIT_OBJECTS];
> +    WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS];
> +    void *opaque[MAXIMUM_WAIT_OBJECTS];
>  } WaitObjects;
>
>  static WaitObjects wait_objects = {0};
> @@ -395,6 +395,9 @@ void qemu_del_wait_object(HANDLE handle,
> WaitObjectFunc *func, void *opaque)
>          if (w->events[i] == handle) {
>              found = 1;
>          }
> +        if (i == MAXIMUM_WAIT_OBJECTS - 1) {
> +            break;
> +        }
>

hmm


>          if (found) {
>              w->events[i] = w->events[i + 1];
>              w->func[i] = w->func[i + 1];
>

The way deletion works is by moving the i+1 element (which is always zeroed
for i == MAXIMUM_WAIT_OBJECTS) to i.

After your patch, for i == MAXIMUM_WAIT_OBJECTS, we no longer clear the
last value, and instead rely simply on updated w->num:

    if (found) {
        w->num--;
    }

 So your patch looks ok to me, but I prefer the current code.

Paolo, what do you say?

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