Re: [Qemu-block] [PATCH for 2.9 v3 10/10] block: Fix bdrv_co_flush early return

[Paolo Bonzini]

On 10/04/2017 23:05, Fam Zheng wrote:
> bdrv_inc_in_flight and bdrv_dec_in_flight are mandatory for
> BDRV_POLL_WHILE to work, even for the shortcut case where flush is
> unnecessary. Move the if block to below bdrv_dec_in_flight, and BTW fix
> the variable declaration position.
> 
> Signed-off-by: Fam Zheng <address@hidden>
> ---
>  block/io.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index 00e45ca..bae6947 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -2278,16 +2278,17 @@ static void coroutine_fn bdrv_flush_co_entry(void 
> *opaque)
>  
>  int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
>  {
> -    int ret;
> -
> -    if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
> -        bdrv_is_sg(bs)) {
> -        return 0;
> -    }
> +    int current_gen;
> +    int ret = 0;
>  
>      bdrv_inc_in_flight(bs);
>  
> -    int current_gen = bs->write_gen;
> +    if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
> +        bdrv_is_sg(bs)) {
> +        goto early_exit;
> +    }
> +
> +    current_gen = bs->write_gen;
>  
>      /* Wait until any previous flushes are completed */
>      while (bs->active_flush_req) {
> @@ -2370,6 +2371,7 @@ out:
>      /* Return value is ignored - it's ok if wait queue is empty */
>      qemu_co_queue_next(&bs->flush_queue);
>  
> +early_exit:
>      bdrv_dec_in_flight(bs);
>      return ret;
>  }
> 

Reviewed-by: Paolo Bonzini <address@hidden>