powerpc/mm: Add pte_xchg() helper
We have five locations in 64-bit hash MMU code that do a cmpxchg() of a
PTE. Currently doing it inline OK, but in a future patch we will be
converting the PTEs to __be64 in some configs. In that case we will need
casts at every cmpxchg() site in order to keep sparse happy.
So move the logic into a helper, this is a reasonably nice cleanup on
its own.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
index b2d659c..6fbf983 100644
--- a/arch/powerpc/mm/hash64_64k.c
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -79,8 +79,8 @@
new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED | _PAGE_COMBO;
if (access & _PAGE_RW)
new_pte |= _PAGE_DIRTY;
- } while (old_pte != __cmpxchg_u64((unsigned long *)ptep,
- old_pte, new_pte));
+ } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
+
/*
* Handle the subpage protection bits
*/
@@ -254,8 +254,7 @@
new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
if (access & _PAGE_RW)
new_pte |= _PAGE_DIRTY;
- } while (old_pte != __cmpxchg_u64((unsigned long *)ptep,
- old_pte, new_pte));
+ } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
rflags = htab_convert_pte_flags(new_pte);