On Mon, Jun 08, 2020 at 03:03:05PM +0300, Andy Shevchenko wrote:
> On Mon, Jun 8, 2020 at 1:26 PM Alexander Gordeev <agordeev@xxxxxxxxxxxxx> wrote:
> >
> > Commit 2d6261583be0 ("lib: rework bitmap_parse()") does not
> > take into account order of halfwords on 64-bit big endian
> > architectures. As result (at least) Receive Packet Steering,
> > IRQ affinity masks and runtime kernel test "test_bitmap" get
> > broken on s390.
>
> ...
>
> > +#if defined(__BIG_ENDIAN) && defined(CONFIG_64BIT)
>
> I think it's better to re-use existing patterns.
>
> ipc/sem.c:1682:#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
>
> > +static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
> > +{
> > + maskp += (chunk_idx / 2);
> > + ((u32 *)maskp)[(chunk_idx & 1) ^ 1] = chunk;
> > +}
> > +#else
> > +static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
> > +{
> > + ((u32 *)maskp)[chunk_idx] = chunk;
> > +}
> > +#endif
>
> See below.
>
> ...
>
> > - end = bitmap_get_x32_reverse(start, end, bitmap++);
> > + end = bitmap_get_x32_reverse(start, end, &chunk);
> > if (IS_ERR(end))
> > return PTR_ERR(end);
> > +
> > + save_x32_chunk(maskp, chunk, chunk_idx++);
>
> Can't we simple do
>
> int chunk_index = 0;
> ...
> do {
> #if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
> end = bitmap_get_x32_reverse(start, end,
> bitmap[chunk_index ^ 1]);
> #else
> end = bitmap_get_x32_reverse(start, end, bitmap[chunk_index]);
> #endif
> ...
> } while (++chunk_index);
>
> ?
Well, unless we ignore coding style 21) Conditional Compilation
we could. Do you still insist it would be better?
Thanks for the review!
> --
> With Best Regards,
> Andy Shevchenko
