On Thu, 13 Apr 2017 17:05:27 +1000 Alexey Kardashevskiy <a...@ozlabs.ru> wrote:
> When the userspace requests a small TCE table (which takes less than > the system page size) and more than 1 TCE level, the existing code > returns a single page size which is a bug as each additional TCE level > requires at least one page and this is what > pnv_pci_ioda2_table_alloc_pages() does. And we end up seeing > WARN_ON(!ret && ((*ptbl)->it_allocated_size != table_size)) > in drivers/vfio/vfio_iommu_spapr_tce.c. > > This replaces incorrect _ALIGN_UP() (which aligns zero up to zero) with > max_t() to fix the bug. > > Besides removing WARN_ON(), there should be no other changes in > behaviour. Ping? > > Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > --- > arch/powerpc/platforms/powernv/pci-ioda.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c > b/arch/powerpc/platforms/powernv/pci-ioda.c > index 6d0da5dfc955..a0d046adcf45 100644 > --- a/arch/powerpc/platforms/powernv/pci-ioda.c > +++ b/arch/powerpc/platforms/powernv/pci-ioda.c > @@ -2538,7 +2538,8 @@ static unsigned long pnv_pci_ioda2_get_table_size(__u32 > page_shift, > > tce_table_size /= direct_table_size; > tce_table_size <<= 3; > - tce_table_size = _ALIGN_UP(tce_table_size, direct_table_size); > + tce_table_size = max_t(unsigned long, > + tce_table_size, direct_table_size); > } > > return bytes; -- Alexey
