Re: [Qemu-devel] [PATCH] qcow2: remove useless NULL check

[Max Reitz <mreitz@redhat.com>]

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On 08.02.2017 09:09, Marc-André Lureau wrote:
> g_strdup() already handles the case where the argument is NULL.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  block/qcow2.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 96fb8a8f16..9114218030 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2016,8 +2016,8 @@ static int qcow2_change_backing_file(BlockDriverState *bs,
>      g_free(s->image_backing_file);
>      g_free(s->image_backing_format);
>  
> -    s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
> -    s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
> +    s->image_backing_file = g_strdup(bs->backing_file);
> +    s->image_backing_format = g_strdup(bs->backing_format);

bs->backing_file and bs->backing_format are arrays. They will never be NULL.

The ternary operator tests backing_file and backing_fmt which instead
are pointers. So this is not an equivalent conversion.

Max

>  
>      return qcow2_update_header(bs);
>  }
> 



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