* from swap. But that's a lot of code to duplicate here
* for a rare case, so we simply fetch the page.
*/
-
- /*
- * Do a quick atomic lookup first - this is the fastpath.
- */
- spin_lock(¤t->mm->page_table_lock);
- page = follow_page(mm, uaddr, 0);
- if (likely(page != NULL)) {
- key->shared.pgoff =
- page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- spin_unlock(¤t->mm->page_table_lock);
- return 0;
- }
- spin_unlock(¤t->mm->page_table_lock);
-
- /*
- * Do it the general way.
- */
err = get_user_pages(current, mm, uaddr, 1, 0, 0, &page, NULL);
if (err >= 0) {
key->shared.pgoff =
/*
* The waiting task can free the futex_q as soon as this is written,
* without taking any locks. This must come last.
+ *
+ * A memory barrier is required here to prevent the following store
+ * to lock_ptr from getting ahead of the wakeup. Clearing the lock
+ * at the end of wake_up_all() does not prevent this store from
+ * moving.
*/
+ wmb();
q->lock_ptr = NULL;
}
if (bh1 != bh2)
spin_unlock(&bh2->lock);
+#ifndef CONFIG_MMU
+ /* we don't get EFAULT from MMU faults if we don't have an MMU,
+ * but we might get them from range checking */
+ ret = op_ret;
+ goto out;
+#endif
+
+ if (unlikely(op_ret != -EFAULT)) {
+ ret = op_ret;
+ goto out;
+ }
+
/* futex_atomic_op_inuser needs to both read and write
* *(int __user *)uaddr2, but we can't modify it
* non-atomically. Therefore, if get_user below is not