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blk-cgroup: remove blkg_lookup_check

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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220921180501.1539876-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2022-09-21 20:04:49 +02:00 committed by Jens Axboe
parent 4a69f325aa
commit f753526e32
1 changed files with 10 additions and 26 deletions
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36
block/blk-cgroup.c
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@ -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);