linux-kernel - [PATCH 4/5] mm/hugetlb: Add prot_modify_start/commit sequence for hugetlb update

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Message-Id: <20181011035247.30687-5-aneesh.kumar@linux.ibm.com>
Date:   Thu, 11 Oct 2018 09:22:46 +0530
From:   "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
To:     akpm@...ux-foundation.org, mpe@...erman.id.au,
        benh@...nel.crashing.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
Subject: [PATCH 4/5] mm/hugetlb: Add prot_modify_start/commit sequence for hugetlb update

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.ibm.com>
---
 include/linux/hugetlb.h | 18 ++++++++++++++++++
 mm/hugetlb.c            |  8 +++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 087fd5f48c91..e2a3b0c854eb 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -543,6 +543,24 @@ static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr
 	set_huge_pte_at(mm, addr, ptep, pte);
 }
 #endif
+
+#ifndef huge_ptep_modify_prot_start
+static inline pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
+						unsigned long addr, pte_t *ptep)
+{
+	return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep);
+}
+#endif
+
+#ifndef huge_ptep_modify_prot_commit
+static inline void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
+						unsigned long addr, pte_t *ptep,
+						pte_t old_pte, pte_t pte)
+{
+	set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
+}
+#endif
+
 #else	/* CONFIG_HUGETLB_PAGE */
 struct hstate {};
 #define alloc_huge_page(v, a, r) NULL
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5c390f5a5207..1f3a4df95b2e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4367,10 +4367,12 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
 			continue;
 		}
 		if (!huge_pte_none(pte)) {
-			pte = huge_ptep_get_and_clear(mm, address, ptep);
-			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
+			pte_t old_pte;
+
+			old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
+			pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
 			pte = arch_make_huge_pte(pte, vma, NULL, 0);
-			set_huge_pte_at(mm, address, ptep, pte);
+			huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
 			pages++;
 		}
 		spin_unlock(ptl);
-- 
2.17.1