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Commit 92ed51e6 authored by Paolo Valente's avatar Paolo Valente Committed by Greg Kroah-Hartman
Browse files

block, bfq: get a ref to a group when adding it to a service tree 



commit db37a34c563bf4692b36990ae89005c031385e52 upstream.

BFQ schedules generic entities, which may represent either bfq_queues
or groups of bfq_queues. When an entity is inserted into a service
tree, a reference must be taken, to make sure that the entity does not
disappear while still referred in the tree. Unfortunately, such a
reference is mistakenly taken only if the entity represents a
bfq_queue. This commit takes a reference also in case the entity
represents a group.

Tested-by: default avatarOleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: default avatarChris Evich <cevich@redhat.com>
Signed-off-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e657b1f6

block/bfq-cgroup.c

+1 −1
Original line number Diff line number Diff line
@@ -332,7 +332,7 @@ static void bfqg_put(struct bfq_group *bfqg) 
		kfree(bfqg);

}



static void bfqg_and_blkg_get(struct bfq_group *bfqg)

void bfqg_and_blkg_get(struct bfq_group *bfqg)

{

	/* see comments in bfq_bic_update_cgroup for why refcounting bfqg */

	bfqg_get(bfqg);

block/bfq-iosched.h

+1 −0
Original line number Diff line number Diff line
@@ -978,6 +978,7 @@ struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, 
struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);

struct bfq_group *bfqq_group(struct bfq_queue *bfqq);

struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);

void bfqg_and_blkg_get(struct bfq_group *bfqg);

void bfqg_and_blkg_put(struct bfq_group *bfqg);



#ifdef CONFIG_BFQ_GROUP_IOSCHED

block/bfq-wf2q.c

+10 −2
Original line number Diff line number Diff line
@@ -536,7 +536,9 @@ static void bfq_get_entity(struct bfq_entity *entity) 
		bfqq->ref++;

		bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d",

			     bfqq, bfqq->ref);

	}

	} else

		bfqg_and_blkg_get(container_of(entity, struct bfq_group,

					       entity));

}



/**
@@ -650,8 +652,14 @@ static void bfq_forget_entity(struct bfq_service_tree *st, 


	entity->on_st = false;

	st->wsum -= entity->weight;

	if (bfqq && !is_in_service)

	if (is_in_service)

		return;



	if (bfqq)

		bfq_put_queue(bfqq);

	else

		bfqg_and_blkg_put(container_of(entity, struct bfq_group,

					       entity));

}



/**