uprobes: Fold xol_alloc_area() into get_xol_area()

Currently only xol_get_insn_slot() does get_xol_area() + xol_alloc_area(),
but this will have more users and we do not want to copy-and-paste this
code. This patch simply moves xol_alloc_area() into get_xol_area() to
simplify the current and future code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

1 files changed, 16 insertions, 22 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ea2e2a85479a..7e3e5c5b0d88 100644
--- a/kernel/events/uprobes.c
+++ b/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.