Re: [PATCH v2] md/raid5: Convert stripe_head's "dev" to flexible array member

[Song Liu]

On Tue, May 30, 2023 at 4:00 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> On Tue, May 23, 2023 at 10:43:52AM -0700, Song Liu wrote:
> > On Mon, May 22, 2023 at 2:21 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >
> > > Replace old-style 1-element array of "dev" in struct stripe_head with
> > > modern C99 flexible array. In the future, we can additionally annotate
> > > it with the run-time size, found in the "disks" member.
> > >
> > > Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> > > Cc: linux-raid@xxxxxxxxxxxxxxx
> > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> > > ---
> > > It looks like this memory calculation:
> > >
> > >         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
> > >                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
> > >
> > > ... was already buggy (i.e. it included the single "dev" bytes in the
> > > result). However, I'm not entirely sure if that is the right analysis,
> > > since "dev" is not related to struct bio nor PAGE_SIZE?
> > >
> > > v1: https://lore.kernel.org/all/20230517233313.never.130-kees@xxxxxxxxxx/
> > > v2: use new struct_size_t() helper from
> > >     https://lore.kernel.org/lkml/20230522211810.never.421-kees@xxxxxxxxxx/
> >
> > LTGM. Thanks!
>
> Thanks!
>
> > I will hold this for a while until struct_size_t() merged.
>
> Since my tree will introduce struct_size_t(), I will just carry it
> there.

Sounds good! You can add

Acked-by: Song Liu <song@xxxxxxxxxx>

Thanks,
Song