[PATCH 15/22] mm: only initialise pt_share_count for user pgtables

[Kevin Brodsky <kevin.brodsky@arm.com>]

ptdesc_pmd_pts_init() initialises the pt_share_count ptdesc field.
That field is only used for hugetlb tracking purposes, so there is
no need to initialise it for kernel page tables. Skip the call for
kernel page tables, like pmd_ptlock_init().

From now on pagetable_*_ctor() and pagetable_dtor() do nothing for
kernel page tables.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 include/linux/mm.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 94f0fb1c662a..b217ccbed5a3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3905,9 +3905,12 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
 static inline bool pagetable_pmd_ctor(struct mm_struct *mm,
 				      struct ptdesc *ptdesc)
 {
-	if (!mm_is_kernel(mm) && !pmd_ptlock_init(ptdesc))
-		return false;
-	ptdesc_pmd_pts_init(ptdesc);
+	if (!mm_is_kernel(mm)) {
+		if (!pmd_ptlock_init(ptdesc))
+			return false;
+		ptdesc_pmd_pts_init(ptdesc);
+	}
+
 	return true;
 }
 

-- 
2.51.2