1 files changed, 27 insertions, 26 deletions

diff --git a/mm/madvise.c b/mm/madvise.c
index 76eb4193acd..d9ae2067952 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -11,6 +11,7 @@
 #include <linux/mempolicy.h>
 #include <linux/hugetlb.h>
 #include <linux/sched.h>
+#include <linux/ksm.h>
 
 /*
  * Any behaviour which results in changes to the vma->vm_flags needs to
@@ -41,7 +42,7 @@ static long madvise_behavior(struct vm_area_struct * vma,
 	struct mm_struct * mm = vma->vm_mm;
 	int error = 0;
 	pgoff_t pgoff;
-	int new_flags = vma->vm_flags;
+	unsigned long new_flags = vma->vm_flags;
 
 	switch (behavior) {
 	case MADV_NORMAL:
@@ -57,8 +58,18 @@ static long madvise_behavior(struct vm_area_struct * vma,
 		new_flags |= VM_DONTCOPY;
 		break;
 	case MADV_DOFORK:
+		if (vma->vm_flags & VM_IO) {
+			error = -EINVAL;
+			goto out;
+		}
 		new_flags &= ~VM_DONTCOPY;
 		break;
+	case MADV_MERGEABLE:
+	case MADV_UNMERGEABLE:
+		error = ksm_madvise(vma, start, end, behavior, &new_flags);
+		if (error)
+			goto out;
+		break;
 	}
 
 	if (new_flags == vma->vm_flags) {
@@ -211,37 +222,16 @@ static long
 madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
 		unsigned long start, unsigned long end, int behavior)
 {
-	long error;
-
 	switch (behavior) {
-	case MADV_DOFORK:
-		if (vma->vm_flags & VM_IO) {
-			error = -EINVAL;
-			break;
-		}
-	case MADV_DONTFORK:
-	case MADV_NORMAL:
-	case MADV_SEQUENTIAL:
-	case MADV_RANDOM:
-		error = madvise_behavior(vma, prev, start, end, behavior);
-		break;
 	case MADV_REMOVE:
-		error = madvise_remove(vma, prev, start, end);
-		break;
-
+		return madvise_remove(vma, prev, start, end);
 	case MADV_WILLNEED:
-		error = madvise_willneed(vma, prev, start, end);
-		break;
-
+		return madvise_willneed(vma, prev, start, end);
 	case MADV_DONTNEED:
-		error = madvise_dontneed(vma, prev, start, end);
-		break;
-
+		return madvise_dontneed(vma, prev, start, end);
 	default:
-		BUG();
-		break;
+		return madvise_behavior(vma, prev, start, end, behavior);
 	}
-	return error;
 }
 
 static int
@@ -256,12 +246,17 @@ madvise_behavior_valid(int behavior)
 	case MADV_REMOVE:
 	case MADV_WILLNEED:
 	case MADV_DONTNEED:
+#ifdef CONFIG_KSM
+	case MADV_MERGEABLE:
+	case MADV_UNMERGEABLE:
+#endif
 		return 1;
 
 	default:
 		return 0;
 	}
 }
+
 /*
  * The madvise(2) system call.
  *
@@ -286,6 +281,12 @@ madvise_behavior_valid(int behavior)
  *		so the kernel can free resources associated with it.
  *  MADV_REMOVE - the application wants to free up the given range of
  *		pages and associated backing store.
+ *  MADV_DONTFORK - omit this area from child's address space when forking:
+ *		typically, to avoid COWing pages pinned by get_user_pages().
+ *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
+ *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
+ *		this area with pages of identical content from other such areas.
+ *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
  *
  * return values:
  *  zero    - success