Date: Wed, 28 Oct 2015 09:53:50 -0400
From: Jeff Cody <jcody@redhat.com>
Message-ID: <20151028135349.GB1600@localhost.localdomain>
References: <1446029211-27148-1-git-send-email-kwolf@redhat.com>
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In-Reply-To: <1446029211-27148-1-git-send-email-kwolf@redhat.com>
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] block: Consider all child
 nodes in bdrv_requests_pending()
To: Kevin Wolf <kwolf@redhat.com>
Cc: stefanha@redhat.com, famz@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, mreitz@redhat.com

On Wed, Oct 28, 2015 at 11:46:51AM +0100, Kevin Wolf wrote:
> The function manually recursed into bs->file and bs->backing to check
> whether there were any requests pending, but it ignored other children.
> 
> There's no need to special case file and backing here, so just replace
> these two explicit recursions by a loop recursing for all child nodes.
> 
> Reported-by: Max Reitz <mreitz@redhat.com>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/io.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index 5ac6256..8dcad3b 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -216,6 +216,8 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs)
>  /* Check if any requests are in-flight (including throttled requests) */
>  bool bdrv_requests_pending(BlockDriverState *bs)
>  {
> +    BdrvChild *child;
> +
>      if (!QLIST_EMPTY(&bs->tracked_requests)) {
>          return true;
>      }
> @@ -225,12 +227,13 @@ bool bdrv_requests_pending(BlockDriverState *bs)
>      if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) {
>          return true;
>      }
> -    if (bs->file && bdrv_requests_pending(bs->file->bs)) {
> -        return true;
> -    }
> -    if (bs->backing && bdrv_requests_pending(bs->backing->bs)) {
> -        return true;
> +
> +    QLIST_FOREACH(child, &bs->children, next) {
> +        if (bdrv_requests_pending(child->bs)) {
> +            return true;
> +        }
>      }
> +
>      return false;
>  }
>  
> -- 
> 1.8.3.1
> 
> 

Reviewed-by: Jeff Cody <jcody@redhat.com>