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From: Tejun Heo <tj@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Michal Koutný" <mkoutny@suse.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Hillf Danton" <hdanton@sina.com>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Marco Elver" <elver@google.com>,
	"Zefan Li" <lizefan.x@bytedance.com>,
	tglx@linutronix.de,
	syzbot+6ea37e2e6ffccf41a7e6@syzkaller.appspotmail.com
Subject: Re: [PATCH v4 6/6] kernfs: Use RCU to access kernfs_node::name.
Date: Fri, 24 Jan 2025 13:41:17 -1000	[thread overview]
Message-ID: <Z5QlHcCErrALjWfG@slm.duckdns.org> (raw)
In-Reply-To: <20250124174614.866884-7-bigeasy@linutronix.de>

Hello,

On Fri, Jan 24, 2025 at 06:46:14PM +0100, Sebastian Andrzej Siewior wrote:
> Using RCU lifetime rules to access kernfs_node::name can avoid the
> trouble kernfs_rename_lock in kernfs_name() and kernfs_path_from_node()
> if the fs was created with KERNFS_ROOT_INVARIANT_PARENT.

Maybe explain why we want to do this?

> +static inline const char *kernfs_rcu_get_name(const struct kernfs_node *kn)
> +{
> +	return rcu_dereference_check(kn->name, kernfs_root_is_locked(kn));
> +}

Can you drop "get" from the accessors? Other accessors don't have it and it
gets confusing with reference counting operations.

Thanks.

-- 
tejun

  reply	other threads:[~2025-01-24 23:41 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-24 17:46 [PATCH v4 0/6] kernfs: Use RCU to access kernfs_node::{parent|name} Sebastian Andrzej Siewior
2025-01-24 17:46 ` [PATCH v4 1/6] kernfs: Acquire kernfs_rwsem in kernfs_notify_workfn() Sebastian Andrzej Siewior
2025-01-24 23:09   ` Tejun Heo
2025-01-24 17:46 ` [PATCH v4 2/6] kernfs: Acquire kernfs_rwsem in kernfs_get_parent_dentry() Sebastian Andrzej Siewior
2025-01-24 23:11   ` Tejun Heo
2025-01-27  8:42     ` Sebastian Andrzej Siewior
2025-01-24 17:46 ` [PATCH v4 3/6] kernfs: Acquire kernfs_rwsem in kernfs_node_dentry() Sebastian Andrzej Siewior
2025-01-24 23:12   ` Tejun Heo
2025-01-24 17:46 ` [PATCH v4 4/6] kernfs: Don't re-lock kernfs_root::kernfs_rwsem in kernfs_fop_readdir() Sebastian Andrzej Siewior
2025-01-24 23:15   ` Tejun Heo
2025-01-27  9:02     ` Sebastian Andrzej Siewior
2025-01-27 18:01       ` Tejun Heo
2025-01-24 17:46 ` [PATCH v4 5/6] kernfs: Use RCU to access kernfs_node::parent Sebastian Andrzej Siewior
2025-01-24 23:35   ` Tejun Heo
2025-01-27 16:25     ` Sebastian Andrzej Siewior
2025-01-27 18:00       ` Tejun Heo
2025-01-24 17:46 ` [PATCH v4 6/6] kernfs: Use RCU to access kernfs_node::name Sebastian Andrzej Siewior
2025-01-24 23:41   ` Tejun Heo [this message]
2025-01-27 16:17     ` Sebastian Andrzej Siewior

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