cfq-iosched: fix bug with aliased request and cooperation detection (3ac6c9f8) · Commits · 戴 / test

cfq_prio_tree_lookup() should return the direct match, yet it always returns zero. Fix that. cfq_prio_tree_add() assumes that we don't get a direct match, while it is very possible that we do. Using O_DIRECT, you can have different cfqq with matching requests, since you don't have the page cache to serialize things for you. Fix this bug by only adding the cfqq if there isn't an existing match. Signed-off-by:

Jens Axboe <jens.axboe@oracle.com>

block/cfq-iosched.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -584,12 +584,13 @@ cfq_prio_tree_lookup(struct cfq_data *cfqd, int ioprio, sector_t sector,
		else
		break;
		p = n;
		cfqq = NULL;
		}

		*ret_parent = parent;
		if (rb_link)
		*rb_link = p;
		return NULL;
		return cfqq;
		}

		static void cfq_prio_tree_add(struct cfq_data cfqd, struct cfq_queue cfqq)
		@@ -608,11 +609,11 @@ static void cfq_prio_tree_add(struct cfq_data cfqd, struct cfq_queue cfqq)

		__cfqq = cfq_prio_tree_lookup(cfqd, cfqq->ioprio, cfqq->next_rq->sector,
		&parent, &p);
		BUG_ON(__cfqq);

		if (!__cfqq) {
		rb_link_node(&cfqq->p_node, parent, p);
		rb_insert_color(&cfqq->p_node, root);
		}
		}

		/*
		* Update cfqq's position in the service tree.

Admin message