Re: [Qemu-block] [PATCH v3 11/19] block-backend: Decrease in_flight only after callback

[Paolo Bonzini]

On 20/09/2018 18:19, Kevin Wolf wrote:
> Request callbacks can do pretty much anything, including operations that
> will yield from the coroutine (such as draining the backend). In that
> case, a decreased in_flight would be visible to other code and could
> lead to a drain completing while the callback hasn't actually completed
> yet.
> 
> Signed-off-by: Kevin Wolf <address@hidden>
> Reviewed-by: Fam Zheng <address@hidden>
> Reviewed-by: Max Reitz <address@hidden>
> ---
>  block/block-backend.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 63eb2d10cd..5e5e60ff8d 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -1340,8 +1340,8 @@ static const AIOCBInfo blk_aio_em_aiocb_info = {
>  static void blk_aio_complete(BlkAioEmAIOCB *acb)
>  {
>      if (acb->has_returned) {
> -        blk_dec_in_flight(acb->rwco.blk);
>          acb->common.cb(acb->common.opaque, acb->rwco.ret);
> +        blk_dec_in_flight(acb->rwco.blk);
>          qemu_aio_unref(acb);
>      }
>  }
> 

If you'd like to include something in the commit message from my last
email on the subject it would be nice, otherwise

Reviewed-by: Paolo Bonzini <address@hidden>

Paolo