Commit ae994ea9 authored by Jens Axboe's avatar Jens Axboe
Browse files

cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL 



Commit 9470e4a6 only covered the initial bug report, there are
other spots in CFQ where we need to check that we actually have
a valid cfq_group_data structure.

Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data")
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 9470e4a6

block/cfq-iosched.c

+11 −1
Original line number Diff line number Diff line
@@ -1754,6 +1754,9 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of, 
	ret = -EINVAL;

	cfqg = blkg_to_cfqg(ctx.blkg);

	cfqgd = blkcg_to_cfqgd(blkcg);

	if (!cfqg || !cfqgd)

		goto err;



	if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) {

		if (!is_leaf_weight) {

			cfqg->dev_weight = ctx.v;
@@ -1765,6 +1768,7 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of, 
		ret = 0;

	}



err:

	blkg_conf_finish(&ctx);

	return ret ?: nbytes;

}
@@ -1787,12 +1791,17 @@ static int __cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft, 
	struct blkcg *blkcg = css_to_blkcg(css);

	struct blkcg_gq *blkg;

	struct cfq_group_data *cfqgd;

	int ret = 0;



	if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX)

		return -EINVAL;



	spin_lock_irq(&blkcg->lock);

	cfqgd = blkcg_to_cfqgd(blkcg);

	if (!cfqgd) {

		ret = -EINVAL;

		goto out;

	}



	if (!is_leaf_weight)

		cfqgd->weight = val;
@@ -1814,8 +1823,9 @@ static int __cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft, 
		}

	}



out:

	spin_unlock_irq(&blkcg->lock);

	return 0;

	return ret;

}



static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,