On 18 September 2012 20:33, Andrew Morton [off-list ref] wrote:

On Sat, 15 Sep 2012 15:38:33 +0200
Ralf Baechle [off-list ref] wrote:

quoted

On Tue, Sep 11, 2012 at 05:47:15PM +0100, Will Deacon wrote:

quoted

The update_mmu_cache() takes a pointer (to pte_t by default) as the last
argument but the huge_memory.c passes a pmd_t value. The patch changes
the argument to the pmd_t * pointer.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steve Capper <redacted>
Signed-off-by: Will Deacon <redacted>
---
 mm/huge_memory.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 57c4b93..4aa6d02 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c

@@ -934,7 +934,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
            entry = pmd_mkyoung(orig_pmd);
            entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
            if (pmdp_set_access_flags(vma, haddr, pmd, entry,  1))
-                   update_mmu_cache(vma, address, entry);
+                   update_mmu_cache(vma, address, pmd);

Documentation/cachetlb.txt will need an update as well.  Currently it says:

5) void update_mmu_cache(struct vm_area_struct *vma,
                         unsigned long address, pte_t *ptep)

Yes please.

Should we just use a generic (void *) for the last argument or force a
cast in mm/huge_memory.c?

Ralf's point is that transparent huge page code calls update_mmu_cache
with a (pmd_t *) as the last argument. This could make sense for THP
as it assumes that huge pages can only be created at the pmd level.
But that's unlike mm/hugetlb.c which casts huge page types to pte_t,
even though on ARM they are implemented at the pmd level.

On ARM (with VIPT caches) update_mmu_cache() is empty like on x86,
though a static inline rather than macro.

-- 
Catalin