Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc mremap fix from Ben Herrenschmidt:
 "This is the patch that I had sent after -rc8 and which we decided to
  wait before merging.  It's based on a different tree than my -next
  branch (it needs some pre-reqs that were in -rc4 or so while my -next
  is based on -rc1) so I left it as a separate branch for your to pull.
  It's identical to the request I did 2 or 3 weeks back.

  This fixes crashes in mremap with THP on powerpc.

  The fix however requires a small change in the generic code.  It moves
  a condition into a helper we can override from the arch which is
  harmless, but it *also* slightly changes the order of the set_pmd and
  the withdraw & deposit, which should be fine according to Kirill (who
  wrote that code) but I agree -rc8 is a bit late...

  It was acked by Kirill and Andrew told me to just merge it via powerpc"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/thp: Fix crash on mremap

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index 4a191c472867..d27960c89a71 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -558,5 +558,19 @@ extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 #define __HAVE_ARCH_PMDP_INVALIDATE
 extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			    pmd_t *pmdp);
+
+#define pmd_move_must_withdraw pmd_move_must_withdraw
+typedef struct spinlock spinlock_t;
+static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
+					 spinlock_t *old_pmd_ptl)
+{
+	/*
+	 * Archs like ppc64 use pgtable to store per pmd
+	 * specific information. So when we switch the pmd,
+	 * we should also withdraw and deposit the pgtable
+	 */
+	return true;
+}
+
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */