[PATCH rc 4/5] iommupt: Check for missing PAGE_SIZE in the pgsize_bitmap

[Jason Gunthorpe <jgg@nvidia.com>]

Sashiko pointed out that the driver could drop PAGE_SIZE from the
pgsize_bitmap. That is technically allowed but nothing does it, and
such an iommu_domain would not be used with the DMA API today.

Still, it is against the design and it is trivial to fix up. Lift
the PT_WARN_ON to the if branch and just skip the fast path.

Fixes: dcd6a011a8d5 ("iommupt: Add map_pages op")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/iommu/generic_pt/iommu_pt.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/generic_pt/iommu_pt.h b/drivers/iommu/generic_pt/iommu_pt.h
index 19b6daf88f2ab1..4877b05291c9d4 100644
--- a/drivers/iommu/generic_pt/iommu_pt.h
+++ b/drivers/iommu/generic_pt/iommu_pt.h
@@ -920,8 +920,8 @@ static int NS(map_range)(struct pt_iommu *iommu_table, dma_addr_t iova,
 		return ret;
 
 	/* Calculate target page size and level for the leaves */
-	if (pt_has_system_page_size(common) && len == PAGE_SIZE) {
-		PT_WARN_ON(!(pgsize_bitmap & PAGE_SIZE));
+	if (pt_has_system_page_size(common) && len == PAGE_SIZE &&
+		likely(pgsize_bitmap & PAGE_SIZE)) {
 		if (log2_mod(iova | paddr, PAGE_SHIFT))
 			return -ENXIO;
 		map.leaf_pgsize_lg2 = PAGE_SHIFT;
-- 
2.43.0