Re: [PATCH v4 1/3] util/main-loop: Fix maximum number of wait objects for win32

[Philippe Mathieu-Daudé]

On 19/10/22 12:20, Bin Meng wrote:
> From: Bin Meng <bin.meng@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.meng@windriver.com>
> ---
>
> Changes in v4:
> - make the out of bounds access protection explicit
>
> 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 | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/util/main-loop.c b/util/main-loop.c
> index f00a25451b..de38876064 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};
> @@ -395,7 +395,7 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc 
> *func, void *opaque)
>           if (w->events[i] == handle) {
>               found = 1;
>           }
> -        if (found) {
> +        if (found && i < (MAXIMUM_WAIT_OBJECTS - 1)) {

Matter of style, I find this form easier to review (same logic than
what follows):

           if (found && i + 1 < MAXIMUM_WAIT_OBJECTS) {

>               w->events[i] = w->events[i + 1];
>               w->func[i] = w->func[i + 1];
>               w->opaque[i] = w->opaque[i + 1];

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>