From: Breno Leitao <lei...@debian.org>

[ Upstream commit 984ecdd68de0fa1f63ce205d6c19ef5a7bc67b40 ]

The tbl pointer is being derefenced by IOMMU_PAGE_SIZE prior the check
if it is not NULL.

Just moving the dereference code to after the check, where there will
be guarantee that 'tbl' will not be NULL.

Signed-off-by: Breno Leitao <lei...@debian.org>
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 arch/powerpc/kernel/iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 5f202a566ec5f..9bfdd2510fd5e 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -765,9 +765,9 @@ dma_addr_t iommu_map_page(struct device *dev, struct 
iommu_table *tbl,
 
        vaddr = page_address(page) + offset;
        uaddr = (unsigned long)vaddr;
-       npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl));
 
        if (tbl) {
+               npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl));
                align = 0;
                if (tbl->it_page_shift < PAGE_SHIFT && size >= PAGE_SIZE &&
                    ((unsigned long)vaddr & ~PAGE_MASK) == 0)
-- 
2.20.1

Reply via email to