kernel, oom: fix potential pgd_lock deadlock from __mmdrop

[cascardo/linux.git] / include / linux / sched.h

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 67ea796..c4b5883 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2877,6 +2877,20 @@ static inline void mmdrop(struct mm_struct *mm)
                __mmdrop(mm);
 }
 
+static inline void mmdrop_async_fn(struct work_struct *work)
+{
+       struct mm_struct *mm = container_of(work, struct mm_struct, async_put_work);
+       __mmdrop(mm);
+}
+
+static inline void mmdrop_async(struct mm_struct *mm)
+{
+       if (unlikely(atomic_dec_and_test(&mm->mm_count))) {
+               INIT_WORK(&mm->async_put_work, mmdrop_async_fn);
+               schedule_work(&mm->async_put_work);
+       }
+}
+
 static inline bool mmget_not_zero(struct mm_struct *mm)
 {
        return atomic_inc_not_zero(&mm->mm_users);