1 files changed, 19 insertions, 0 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 2b97e8f04607..e916168b6e0a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -39,6 +39,25 @@ int sysctl_oom_kill_allocating_task;
 int sysctl_oom_dump_tasks = 1;
 static DEFINE_SPINLOCK(zone_scan_lock);
 
+/*
+ * compare_swap_oom_score_adj() - compare and swap current's oom_score_adj
+ * @old_val: old oom_score_adj for compare
+ * @new_val: new oom_score_adj for swap
+ *
+ * Sets the oom_score_adj value for current to @new_val iff its present value is
+ * @old_val.  Usually used to reinstate a previous value to prevent racing with
+ * userspacing tuning the value in the interim.
+ */
+void compare_swap_oom_score_adj(int old_val, int new_val)
+{
+        struct sighand_struct *sighand = current->sighand;
+
+        spin_lock_irq(&sighand->siglock);
+        if (current->signal->oom_score_adj == old_val)
+                current->signal->oom_score_adj = new_val;
+        spin_unlock_irq(&sighand->siglock);
+}
+
 /**
  * test_set_oom_score_adj() - set current's oom_score_adj and return old value
  * @new_val: new oom_score_adj value