[PATCH v10-mte 4/7] arm64: mte: implement CONFIG_ARM64_MTE_COMP

[Alexander Potapenko]

>
> That looks weird... You're casting address of a 'data' to a bitmap
> instead of 'data'. At the 1st glance it makes little sense because
> 'data' is passed as parameter. Moreover, in mte_is_compressed()
> you pass 'data', not '&data'. Can you please comment on your
> intention?

Although `data` is a void*, it actually contains 64 bits of compressed
data, so we pass &data to mte_bitmap_read() to read its contents.
Perhaps I'd better make `data` an unsigned long to avoid confusion.

>
> > +     max_ranges = MTE_MAX_RANGES;
> > +     /* Skip the leading bit indicating the inline case. */
> > +     mte_bitmap_read(bitmap, &bit_pos, 1);
> > +     largest_idx =
> > +             mte_bitmap_read(bitmap, &bit_pos, MTE_BITS_PER_LARGEST_IDX);
>
> Nit: really no need to split the line - we're OK with 100-chars per
> line now.

That's true, but I am relying on clang-format here (maybe we should
extend the limit in .clang-format?)