[PATCH 5/6] introduce thp_ptep_get()

[Naoya Horiguchi]

Casting pmd into pte_t to handle thp is strongly architecture dependent.
This patch introduces a new function to separate this dependency from
independent part.

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
---
 arch/x86/include/asm/pgtable.h |    5 +++++
 fs/proc/task_mmu.c             |    8 ++++----
 include/asm-generic/pgtable.h  |    4 ++++
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git 3.2-rc5.orig/arch/x86/include/asm/pgtable.h 3.2-rc5/arch/x86/include/asm/pgtable.h
index 18601c8..24e4ae1 100644
--- 3.2-rc5.orig/arch/x86/include/asm/pgtable.h
+++ 3.2-rc5/arch/x86/include/asm/pgtable.h
@@ -165,6 +165,11 @@ static inline int has_transparent_hugepage(void)
 {
 	return cpu_has_pse;
 }
+
+static inline pte_t thp_ptep_get(pmd_t *pmd)
+{
+	return *(pte_t *)pmd;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static inline pte_t pte_set_flags(pte_t pte, pteval_t set)
diff --git 3.2-rc5.orig/fs/proc/task_mmu.c 3.2-rc5/fs/proc/task_mmu.c
index 5db15eb..5bf4ccf 100644
--- 3.2-rc5.orig/fs/proc/task_mmu.c
+++ 3.2-rc5/fs/proc/task_mmu.c
@@ -395,7 +395,7 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	spinlock_t *ptl;
 
 	if (pmd_trans_huge_stable(pmd, vma)) {
-		smaps_pte_entry(*(pte_t *)pmd, addr,
+		smaps_pte_entry(thp_ptep_get(pmd), addr,
 				HPAGE_PMD_SIZE, walk);
 		spin_unlock(&walk->mm->page_table_lock);
 		mss->anonymous_thp += HPAGE_PMD_SIZE;
@@ -687,11 +687,11 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	vma = find_vma(walk->mm, addr);
 
 	if (pmd_trans_huge_stable(pmd, vma)) {
+		pte_t huge_pte = thp_ptep_get(pmd);
 		for (; addr != end; addr += PAGE_SIZE) {
 			unsigned long offset = (addr & ~PAGEMAP_WALK_MASK)
 				>> PAGE_SHIFT;
-			pfn = thp_pte_to_pagemap_entry(*(pte_t *)pmd,
-						       offset);
+			pfn = thp_pte_to_pagemap_entry(huge_pte, offset);
 			err = add_to_pagemap(addr, pfn, pm);
 			if (err)
 				break;
@@ -966,7 +966,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 	md = walk->private;
 
 	if (pmd_trans_huge_stable(pmd, md->vma)) {
-		pte_t huge_pte = *(pte_t *)pmd;
+		pte_t huge_pte = thp_ptep_get(pmd);
 		struct page *page;
 
 		page = can_gather_numa_stats(huge_pte, md->vma, addr);
diff --git 3.2-rc5.orig/include/asm-generic/pgtable.h 3.2-rc5/include/asm-generic/pgtable.h
index 76bff2b..f346bdc 100644
--- 3.2-rc5.orig/include/asm-generic/pgtable.h
+++ 3.2-rc5/include/asm-generic/pgtable.h
@@ -434,6 +434,10 @@ static inline int pmd_trans_splitting(pmd_t pmd)
 {
 	return 0;
 }
+static inline pte_t thp_ptep_get(pmd_t *pmd)
+{
+	return 0;
+}
 #ifndef __HAVE_ARCH_PMD_WRITE
 static inline int pmd_write(pmd_t pmd)
 {
-- 
1.7.6.5

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