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

[Denis V. Lunev]

On 9/17/23 13:40, Mike Maslenkin wrote:
> 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.
wow! That is pretty much correct!

What compiler/OS you are using :)

Den