All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Tejun Heo <tj@kernel.org>,
	Ming Lei <ming.lei@redhat.com>,
	Changhui Zhong <czhong@redhat.com>
Subject: [PATCH 2/3] blk-cgroup: avoid to warn !rcu_read_lock_held() in blkg_lookup()
Date: Fri, 17 Nov 2023 10:35:23 +0800	[thread overview]
Message-ID: <20231117023527.3188627-3-ming.lei@redhat.com> (raw)
In-Reply-To: <20231117023527.3188627-1-ming.lei@redhat.com>

So far, all callers either holds spin lock or rcu read explicitly, and
most of the caller has added WARN_ON_ONCE(!rcu_read_lock_held()) or
lockdep_assert_held(&disk->queue->queue_lock).

Remove WARN_ON_ONCE(!rcu_read_lock_held()) from blkg_lookup() for
killing the false positive warning from blkg_conf_prep().

Reported-by: Changhui Zhong <czhong@redhat.com>
Fixes: 83462a6c971c ("blkcg: Drop unnecessary RCU read [un]locks from blkg_conf_prep/finish()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-cgroup.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 624c03c8fe64..fd482439afbc 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -249,8 +249,6 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
 {
 	struct blkcg_gq *blkg;
 
-	WARN_ON_ONCE(!rcu_read_lock_held());
-
 	if (blkcg == &blkcg_root)
 		return q->root_blkg;
 
-- 
2.41.0


  parent reply	other threads:[~2023-11-17  2:35 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-17  2:35 [PATCH 0/3] blk-cgroup: three small fixes Ming Lei
2023-11-17  2:35 ` [PATCH 1/3] blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!" Ming Lei
2023-11-17  2:35 ` Ming Lei [this message]
2023-11-17  2:35 ` [PATCH 3/3] blk-cgroup: bypass blkcg_deactivate_policy after destroying Ming Lei
2023-11-19 14:57   ` Tejun Heo
2023-11-20  0:51     ` Ming Lei
2023-11-17 17:49 ` [PATCH 0/3] blk-cgroup: three small fixes Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20231117023527.3188627-3-ming.lei@redhat.com \
    --to=ming.lei@redhat.com \
    --cc=axboe@kernel.dk \
    --cc=czhong@redhat.com \
    --cc=linux-block@vger.kernel.org \
    --cc=tj@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.