1 files changed, 25 insertions, 32 deletions

diff --git a/mm/ksm.c b/mm/ksm.c
index 1925ffbfb27f..47c885368890 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -28,7 +28,6 @@
 #include <linux/kthread.h>
 #include <linux/wait.h>
 #include <linux/slab.h>
-#include <linux/memcontrol.h>
 #include <linux/rbtree.h>
 #include <linux/memory.h>
 #include <linux/mmu_notifier.h>
@@ -375,6 +374,20 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
 	return (ret & VM_FAULT_OOM) ? -ENOMEM : 0;
 }
 
+static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
+		unsigned long addr)
+{
+	struct vm_area_struct *vma;
+	if (ksm_test_exit(mm))
+		return NULL;
+	vma = find_vma(mm, addr);
+	if (!vma || vma->vm_start > addr)
+		return NULL;
+	if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
+		return NULL;
+	return vma;
+}
+
 static void break_cow(struct rmap_item *rmap_item)
 {
 	struct mm_struct *mm = rmap_item->mm;
@@ -388,15 +401,9 @@ static void break_cow(struct rmap_item *rmap_item)
 	put_anon_vma(rmap_item->anon_vma);
 
 	down_read(&mm->mmap_sem);
-	if (ksm_test_exit(mm))
-		goto out;
-	vma = find_vma(mm, addr);
-	if (!vma || vma->vm_start > addr)
-		goto out;
-	if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
-		goto out;
-	break_ksm(vma, addr);
-out:
+	vma = find_mergeable_vma(mm, addr);
+	if (vma)
+		break_ksm(vma, addr);
 	up_read(&mm->mmap_sem);
 }
 
@@ -422,12 +429,8 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 	struct page *page;
 
 	down_read(&mm->mmap_sem);
-	if (ksm_test_exit(mm))
-		goto out;
-	vma = find_vma(mm, addr);
-	if (!vma || vma->vm_start > addr)
-		goto out;
-	if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
+	vma = find_mergeable_vma(mm, addr);
+	if (!vma)
 		goto out;
 
 	page = follow_page(vma, addr, FOLL_GET);
@@ -673,9 +676,9 @@ error:
 static u32 calc_checksum(struct page *page)
 {
 	u32 checksum;
-	void *addr = kmap_atomic(page, KM_USER0);
+	void *addr = kmap_atomic(page);
 	checksum = jhash2(addr, PAGE_SIZE / 4, 17);
-	kunmap_atomic(addr, KM_USER0);
+	kunmap_atomic(addr);
 	return checksum;
 }
 
@@ -684,11 +687,11 @@ static int memcmp_pages(struct page *page1, struct page *page2)
 	char *addr1, *addr2;
 	int ret;
 
-	addr1 = kmap_atomic(page1, KM_USER0);
-	addr2 = kmap_atomic(page2, KM_USER1);
+	addr1 = kmap_atomic(page1);
+	addr2 = kmap_atomic(page2);
 	ret = memcmp(addr1, addr2, PAGE_SIZE);
-	kunmap_atomic(addr2, KM_USER1);
-	kunmap_atomic(addr1, KM_USER0);
+	kunmap_atomic(addr2);
+	kunmap_atomic(addr1);
 	return ret;
 }
 
@@ -1572,16 +1575,6 @@ struct page *ksm_does_need_to_copy(struct page *page,
 
 	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
 	if (new_page) {
-		/*
-		 * The memcg-specific accounting when moving
-		 * pages around the LRU lists relies on the
-		 * page's owner (memcg) to be valid.  Usually,
-		 * pages are assigned to a new owner before
-		 * being put on the LRU list, but since this
-		 * is not the case here, the stale owner from
-		 * a previous allocation cycle must be reset.
-		 */
-		mem_cgroup_reset_owner(new_page);
 		copy_user_highpage(new_page, page, address, vma);
 
 		SetPageDirty(new_page);