+/*
+ * The next function used by blk_queue_for_each_rl(). It's a bit tricky
+ * because the root blkg uses @q->root_rl instead of its own rl.
+ */
+struct request_list *__blk_queue_next_rl(struct request_list *rl,
+ struct request_queue *q)
+{
+ struct list_head *ent;
+ struct blkcg_gq *blkg;
+
+ /*
+ * Determine the current blkg list_head. The first entry is
+ * root_rl which is off @q->blkg_list and mapped to the head.
+ */
+ if (rl == &q->root_rl) {
+ ent = &q->blkg_list;
+ } else {
+ blkg = container_of(rl, struct blkcg_gq, rl);
+ ent = &blkg->q_node;
+ }
+
+ /* walk to the next list_head, skip root blkcg */
+ ent = ent->next;
+ if (ent == &q->root_blkg->q_node)
+ ent = ent->next;
+ if (ent == &q->blkg_list)
+ return NULL;
+
+ blkg = container_of(ent, struct blkcg_gq, q_node);
+ return &blkg->rl;
+}
+