Re: [Qemu-devel] [PATCH for-2.10] block/qapi: Remove redundat NULL check to silence Coverity

[Jeff Cody <jcody@redhat.com>]

On Mon, Jul 31, 2017 at 02:51:11PM +0200, Kevin Wolf wrote:
> When skipping implicit nodes in bdrv_block_device_info(), we know that
> bs0 is always non-NULL; initially, because it's taken from a BdrvChild

Not to mention, we deference bs0 in the chunk of code right above this, so
we'd segfault anyway if the initial value was NULL.

> and a BdrvChild never has a NULL bs, and after the first iteration
> because implicit nodes always have a backing file.
> 
> Remove the NULL check and add an assertion that the implicit node does
> indeed have a backing file.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>


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



> ---
>  block/qapi.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/block/qapi.c b/block/qapi.c
> index d2b18ee9df..5f1a71f5d2 100644
> --- a/block/qapi.c
> +++ b/block/qapi.c
> @@ -145,8 +145,9 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
>  
>          /* Skip automatically inserted nodes that the user isn't aware of for
>           * query-block (blk != NULL), but not for query-named-block-nodes */
> -        while (blk && bs0 && bs0->drv && bs0->implicit) {
> +        while (blk && bs0->drv && bs0->implicit) {
>              bs0 = backing_bs(bs0);
> +            assert(bs0);
>          }
>      }
>  
> -- 
> 2.13.3
> 
>