iommu/tegra-smmu: Fix page table lookup in unmap/iova_to_phys methods
Fix the page table lookup in the unmap and iova_to_phys methods.
Neither of these methods should allocate a page table; a missing page
table should be treated the same as no mapping present.
More importantly, using as_get_pte() for an IOVA corresponding with a
non-present page table entry increments the use-count for the page
table, on the assumption that the caller of as_get_pte() is going to
setup a mapping. This is an incorrect assumption.
Fix both of these bugs by providing a separate helper which only looks
up the page table, but never allocates it. This is akin to pte_offset()
for CPU page tables.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>
1 file changed