bfq: fix typos in comments about B-WF2Q+ algorithm

The start time of eligible entity should be less than or equal to
the current virtual time, and the entity in idle tree has a finish
time being greater than the current virtual time.
Signed-off-by: NHou Tao <houtao1@huawei.com>
Reviewed-by: NPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/bfq-iosched.h

@@ -52,7 +52,7 @@ struct bfq_entity;
 struct bfq_service_tree {
 	/* tree for active entities (i.e., those backlogged) */
 	struct rb_root active;
-	/* tree for idle entities (i.e., not backlogged, with V <= F_i)*/
+	/* tree for idle entities (i.e., not backlogged, with V < F_i)*/
 	struct rb_root idle;
 
 	/* idle entity with minimum F_i */

block/bfq-wf2q.c

@@ -1297,7 +1297,7 @@ static void bfq_update_vtime(struct bfq_service_tree *st, u64 new_value)
  *
  * This function searches the first schedulable entity, starting from the
  * root of the tree and going on the left every time on this side there is
- * a subtree with at least one eligible (start >= vtime) entity. The path on
+ * a subtree with at least one eligible (start <= vtime) entity. The path on
  * the right is followed only if a) the left subtree contains no eligible
  * entities and b) no eligible entity has been found yet.
  */