Re: [PATCH 06/21] parallels: refactor path when we need to re-check image in parallels_open

[Mike Maslenkin]

This patch generates a warning.

On Fri, Sep 15, 2023 at 9:41 PM Denis V. Lunev <den@openvz.org> wrote:
>
> More conditions follows thus the check should be more scalable.
>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> ---
>  block/parallels.c | 19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/block/parallels.c b/block/parallels.c
> index 8f223bfd89..aa29df9f77 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -1065,7 +1065,7 @@ static int parallels_open(BlockDriverState *bs, QDict 
> *options, int flags,
>      int ret, size, i;
>      int64_t file_nb_sectors, sector;
>      uint32_t data_start;
> -    bool data_off_is_correct;
> +    bool need_check = false;
>
>      ret = parallels_opts_prealloc(bs, options, errp);
>      if (ret < 0) {
> @@ -1133,11 +1133,12 @@ static int parallels_open(BlockDriverState *bs, QDict 
> *options, int flags,
>      s->bat_bitmap = (uint32_t *)(s->header + 1);
>
>      if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) {
> -        s->header_unclean = true;
> +        need_check = s->header_unclean = true;
>      }
>
> -    data_off_is_correct = parallels_test_data_off(s, file_nb_sectors,
> -                                                  &data_start);
> +    need_check = need_check ||
> +                 !parallels_test_data_off(s, file_nb_sectors, &data_start);
> +

../block/parallels.c:1139:18: warning: variable 'data_start' is used
uninitialized whenever '||' condition is true
[-Wsometimes-uninitialized]
    need_check = need_check ||
                 ^~~~~~~~~~
../block/parallels.c:1142:21: note: uninitialized use occurs here
    s->data_start = data_start;
                    ^~~~~~~~~~
../block/parallels.c:1139:18: note: remove the '||' if its condition
is always false
    need_check = need_check ||
                 ^~~~~~~~~~~~~
../block/parallels.c:1067:24: note: initialize the variable
'data_start' to silence this warning
    uint32_t data_start;
                       ^
                        = 0
1 warning generated.


Regards,
Mike.