[PATCH 15/35] mm: add pmd_special() check for pmd_trans_huge_lock()

[yulei . kernel]

From: Yulei Zhang <yuleixzh...@tencent.com>

As dmem-pmd had been distinguished from thp-pmd, we need to add
pmd_special() such that pmd_trans_huge_lock could fetch ptl
for dmem huge pmd and treat it as stable pmd.

Signed-off-by: Chen Zhuo <sagazc...@tencent.com>
Signed-off-by: Yulei Zhang <yuleixzh...@tencent.com>
---
 include/linux/huge_mm.h | 3 ++-
 mm/huge_memory.c        | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 8a8bc46a2432..b7381e5aafe5 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -245,7 +245,8 @@ static inline int is_swap_pmd(pmd_t pmd)
 static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
                struct vm_area_struct *vma)
 {
-       if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
+       if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd)
+               || pmd_devmap(*pmd) || pmd_special(*pmd))
                return __pmd_trans_huge_lock(pmd, vma);
        else
                return NULL;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 7ff29cc3d55c..531493a0bc82 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1862,7 +1862,7 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct 
vm_area_struct *vma)
        spinlock_t *ptl;
        ptl = pmd_lock(vma->vm_mm, pmd);
        if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) ||
-                       pmd_devmap(*pmd)))
+                       pmd_devmap(*pmd) || pmd_special(*pmd)))
                return ptl;
        spin_unlock(ptl);
        return NULL;
-- 
2.28.0