1 files changed, 14 insertions, 54 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index bed0834..4206706 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1047,15 +1047,13 @@ static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemap
 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			     struct mm_walk *walk)
 {
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = walk->vma;
 	struct pagemapread *pm = walk->private;
 	spinlock_t *ptl;
 	pte_t *pte, *orig_pte;
 	int err = 0;
 
-	/* find the first VMA at or above 'addr' */
-	vma = find_vma(walk->mm, addr);
-	if (vma && pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
 		int pmd_flags2;
 
 		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
@@ -1081,55 +1079,20 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	if (pmd_trans_unstable(pmd))
 		return 0;
 
-	while (1) {
-		/* End of address space hole, which we mark as non-present. */
-		unsigned long hole_end;
-
-		if (vma)
-			hole_end = min(end, vma->vm_start);
-		else
-			hole_end = end;
-
-		for (; addr < hole_end; addr += PAGE_SIZE) {
-			pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
-
-			err = add_to_pagemap(addr, &pme, pm);
-			if (err)
-				return err;
-		}
-
-		if (!vma || vma->vm_start >= end)
-			break;
-		/*
-		 * We can't possibly be in a hugetlb VMA. In general,
-		 * for a mm_walk with a pmd_entry and a hugetlb_entry,
-		 * the pmd_entry can only be called on addresses in a
-		 * hugetlb if the walk starts in a non-hugetlb VMA and
-		 * spans a hugepage VMA. Since pagemap_read walks are
-		 * PMD-sized and PMD-aligned, this will never be true.
-		 */
-		BUG_ON(is_vm_hugetlb_page(vma));
-
-		/* Addresses in the VMA. */
-		orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
-		for (; addr < min(end, vma->vm_end); pte++, addr += PAGE_SIZE) {
-			pagemap_entry_t pme;
-
-			pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
-			err = add_to_pagemap(addr, &pme, pm);
-			if (err)
-				break;
-		}
-		pte_unmap_unlock(orig_pte, ptl);
+	/*
+	 * We can assume that @vma always points to a valid one and @end never
+	 * goes beyond vma->vm_end.
+	 */
+	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	for (; addr < end; pte++, addr += PAGE_SIZE) {
+		pagemap_entry_t pme;
 
+		pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
+		err = add_to_pagemap(addr, &pme, pm);
 		if (err)
-			return err;
-
-		if (addr == end)
 			break;
-
-		vma = find_vma(walk->mm, addr);
 	}
+	pte_unmap_unlock(orig_pte, ptl);
 
 	cond_resched();
 
@@ -1155,15 +1118,12 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
 				 struct mm_walk *walk)
 {
 	struct pagemapread *pm = walk->private;
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = walk->vma;
 	int err = 0;
 	int flags2;
 	pagemap_entry_t pme;
 
-	vma = find_vma(walk->mm, addr);
-	WARN_ON_ONCE(!vma);
-
-	if (vma && (vma->vm_flags & VM_SOFTDIRTY))
+	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags2 = __PM_SOFT_DIRTY;
 	else
 		flags2 = 0;