> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Tuesday, June 13, 2023 11:15 AM
>
> On 6/12/23 4:28 PM, Liu, Jingqi wrote:
> > On 6/7/2023 11:51 AM, Lu Baolu wrote:
> >> -
> >> - BUG_ON(!domain->pgsize_bitmap);
> >> -
> >> - pg_size = 1UL << __ffs(domain->pgsize_bitmap);
> >> + pg_size = domain->pgsize_bitmap ? 1UL <<
> >> __ffs(domain->pgsize_bitmap) : 0;
> > Would it be better to add the following check here?
> > if (WARN_ON(!pg_size))
> > return -EINVAL;
> >
> > Instead of checking latter in the loop as follows.
> > if (WARN_ON_ONCE(!pg_size)) {
> > ret = -EINVAL;
> > goto out;
> > }
>
> I am afraid no. Only the paging domains need a valid pg_size. That's the
> reason why I put it after the iommu_is_dma_domain() check. The previous
> code has the same behavior too.
>
You could also add the dma domain check here. pg_size is static
then it makes more sense to verify it once instead of in a loop.
