Hello Simon,
Thank for your review.
On Wed, 4 Oct 2023 13:07:14 +0200
Simon Horman <horms@xxxxxxxxxx> wrote:
> On Tue, Oct 03, 2023 at 10:56:52AM +0200, Köry Maincent wrote:
> > From: Kory Maincent <kory.maincent@xxxxxxxxxxx>
>
> > @@ -448,8 +450,11 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned
> > int nbits, }
> >
> > no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
> > - if (no_mask)
> > - ethnl_bitmap32_clear(bitmap, 0, nbits, mod);
> > + if (no_mask) {
> > + tmp = kcalloc(nbits, sizeof(u32), GFP_KERNEL);
> > + memcpy(tmp, bitmap, nbits);
>
> Hi Köry,
>
> I'm no expert on etnhl bitmaps. But the above doesn't seem correct to me.
> Given that sizeof(u32) == 4:
>
> * The allocation is for nbits * 4 bytes
> * The copy is for its for nbits bytes
> * I believe that bitmap contains space for the value followed by a mask.
> So it seems to me the size of bitmap, in words, is
> DIV_ROUND_UP(nbits, 32) * 2
> And in bytes: DIV_ROUND_UP(nbits, 32) * 16
> But perhaps only half is needed if only the value part of tmp is used.
>
> If I'm on the right track here I'd suggest helpers might be in order.
You are right I should use the same alloc as ethnl_update_bitset with tmp
instead of bitmap32:
u32 small_bitmap32[ETHNL_SMALL_BITMAP_WORDS];
u32 *bitmap32 = small_bitmap32;
if (nbits > ETHNL_SMALL_BITMAP_BITS) {
unsigned int dst_words = DIV_ROUND_UP(nbits, 32);
bitmap32 = kmalloc_array(dst_words, sizeof(u32), GFP_KERNEL);
if (!bitmap32)
return -ENOMEM;
}
But I am still wondering if it needs to be double as you said for the size of
the value followed by the mask. Not sure about it, as ethnl_update_bitset does
not do it.
Regards,
