@@ -72,6 +72,19 @@ __acquires(bitmap->lock)
/* this page has not been allocated yet */
spin_unlock_irq(&bitmap->lock);
+ /* It is possible that this is being called inside a
+ * prepare_to_wait/finish_wait loop from raid5c:make_request().
+ * In general it is not permitted to sleep in that context as it
+ * can cause the loop to spin freely.
+ * That doesn't apply here as we can only reach this point
+ * once with any loop.
+ * When this function completes, either bp[page].map or
+ * bp[page].hijacked. In either case, this function will
+ * abort before getting to this point again. So there is
+ * no risk of a free-spin, and so it is safe to assert
+ * that sleeping here is allowed.
+ */
+ sched_annotate_sleep();
mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
spin_lock_irq(&bitmap->lock);