Commit f753526e authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-cgroup: remove blkg_lookup_check 



The combinations of an error check with an ERR_PTR return and a lookup
with a NULL return leads to ugly handling of the return values in the
callers.  Just open coding the check and the lookup is much simpler.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAndreas Herrmann <aherrmann@suse.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220921180501.1539876-6-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 4a69f325

block/blk-cgroup.c

+10 −26
Original line number Diff line number Diff line
@@ -602,25 +602,6 @@ u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v) 
}

EXPORT_SYMBOL_GPL(__blkg_prfill_u64);



/* Performs queue bypass and policy enabled checks then looks up blkg. */

static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,

					  const struct blkcg_policy *pol,

					  struct request_queue *q)

{

	struct blkcg_gq *blkg;



	WARN_ON_ONCE(!rcu_read_lock_held());

	lockdep_assert_held(&q->queue_lock);



	if (!blkcg_policy_enabled(q, pol))

		return ERR_PTR(-EOPNOTSUPP);



	blkg = blkg_lookup(blkcg, q);

	if (blkg)

		blkg_update_hint(blkcg, blkg);

	return blkg;

}



/**

 * blkcg_conf_open_bdev - parse and open bdev for per-blkg config update

 * @inputp: input string pointer
@@ -697,14 +678,16 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, 
	rcu_read_lock();

	spin_lock_irq(&q->queue_lock);



	blkg = blkg_lookup_check(blkcg, pol, q);

	if (IS_ERR(blkg)) {

		ret = PTR_ERR(blkg);

	if (!blkcg_policy_enabled(q, pol)) {

		ret = -EOPNOTSUPP;

		goto fail_unlock;

	}



	if (blkg)

	blkg = blkg_lookup(blkcg, q);

	if (blkg) {

		blkg_update_hint(blkcg, blkg);

		goto success;

	}



	/*

	 * Create blkgs walking down from blkcg_root to @blkcg, so that all
@@ -740,14 +723,15 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, 
		rcu_read_lock();

		spin_lock_irq(&q->queue_lock);



		blkg = blkg_lookup_check(pos, pol, q);

		if (IS_ERR(blkg)) {

			ret = PTR_ERR(blkg);

		if (!blkcg_policy_enabled(q, pol)) {

			blkg_free(new_blkg);

			ret = -EOPNOTSUPP;

			goto fail_preloaded;

		}



		blkg = blkg_lookup(pos, q);

		if (blkg) {

			blkg_update_hint(pos, blkg);

			blkg_free(new_blkg);

		} else {

			blkg = blkg_create(pos, q, new_blkg);