/*
* Returns true if the task does not share ->mm with another thread/process.
*/
-bool is_single_threaded(struct task_struct *task)
+bool current_is_single_threaded(void)
{
+ struct task_struct *task = current;
struct mm_struct *mm = task->mm;
struct task_struct *p, *t;
bool ret;
- might_sleep();
-
if (atomic_read(&task->signal->live) != 1)
return false;
return true;
ret = false;
- down_write(&mm->mmap_sem);
rcu_read_lock();
for_each_process(p) {
if (unlikely(p->flags & PF_KTHREAD))
goto found;
if (likely(t->mm))
break;
+ /*
+ * t->mm == NULL. Make sure next_thread/next_task
+ * will see other CLONE_VM tasks which might be
+ * forked before exiting.
+ */
+ smp_rmb();
} while_each_thread(p, t);
}
ret = true;
found:
rcu_read_unlock();
- up_write(&mm->mmap_sem);
return ret;
}