From 5a686c8c2ada4a0d3b76c788ab966df9fa7af2f0 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 31 Dec 2012 16:39:49 +0100
Subject: [PATCH] --- yaml --- r: 350091 b: refs/heads/master c:
 9b545df809644912552360054c7bbe8b8a9e01fa h: refs/heads/master i:   350089:
 e9d028325555b9c54af0cb9d963074ca6f0d65ef   350087:
 fdc4f80ede8da5fd1777df4591c428856b7caa35 v: v3

---
 [refs]                        |  2 +-
 trunk/kernel/events/uprobes.c | 38 +++++++++++++++--------------------
 2 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/[refs] b/[refs]
index 3a968db186af..214f5e69ad28 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c8a82538001e1a68f4a319d5a75de90d1f284731
+refs/heads/master: 9b545df809644912552360054c7bbe8b8a9e01fa
diff --git a/trunk/kernel/events/uprobes.c b/trunk/kernel/events/uprobes.c
index ea2e2a85479a..7e3e5c5b0d88 100644
--- a/trunk/kernel/events/uprobes.c
+++ b/trunk/kernel/events/uprobes.c
@@ -1070,27 +1070,21 @@ static int xol_add_vma(struct xol_area *area)
 	return ret;
 }
 
-static struct xol_area *get_xol_area(struct mm_struct *mm)
-{
-	struct xol_area *area;
-
-	area = mm->uprobes_state.xol_area;
-	smp_read_barrier_depends();	/* pairs with wmb in xol_add_vma() */
-
-	return area;
-}
-
 /*
- * xol_alloc_area - Allocate process's xol_area.
- * This area will be used for storing instructions for execution out of
- * line.
+ * get_xol_area - Allocate process's xol_area if necessary.
+ * This area will be used for storing instructions for execution out of line.
  *
  * Returns the allocated area or NULL.
  */
-static struct xol_area *xol_alloc_area(void)
+static struct xol_area *get_xol_area(void)
 {
+	struct mm_struct *mm = current->mm;
 	struct xol_area *area;
 
+	area = mm->uprobes_state.xol_area;
+	if (area)
+		goto ret;
+
 	area = kzalloc(sizeof(*area), GFP_KERNEL);
 	if (unlikely(!area))
 		goto out;
@@ -1113,7 +1107,10 @@ static struct xol_area *xol_alloc_area(void)
  free_area:
 	kfree(area);
  out:
-	return get_xol_area(current->mm);
+	area = mm->uprobes_state.xol_area;
+ ret:
+	smp_read_barrier_depends();     /* pairs with wmb in xol_add_vma() */
+	return area;
 }
 
 /*
@@ -1189,14 +1186,11 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot
 	unsigned long offset;
 	void *vaddr;
 
-	area = get_xol_area(current->mm);
-	if (!area) {
-		area = xol_alloc_area();
-		if (!area)
-			return 0;
-	}
-	current->utask->xol_vaddr = xol_take_insn_slot(area);
+	area = get_xol_area();
+	if (!area)
+		return 0;
 
+	current->utask->xol_vaddr = xol_take_insn_slot(area);
 	/*
 	 * Initialize the slot if xol_vaddr points to valid
 	 * instruction slot.