From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Pavol Sakac <sakacpav@amazon.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Tejun Heo <tj@kernel.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Danilo Krummrich <dakr@kernel.org>,
driver-core@lists.linux.dev, linux-kernel@vger.kernel.org,
Xu Yang <xu.yang_2@nxp.com>,
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>,
nh-open-source@amazon.com
Subject: Re: [PATCH 1/3] kernfs: activate nodes while linking them
Date: Fri, 11 Sep 2026 21:12:31 +0300 [thread overview]
Message-ID: <aqREj_l5fMCZwX4f@ashevche-desk.local> (raw)
In-Reply-To: <20260911171639.68348-1-sakacpav@amazon.de>
On Fri, Sep 11, 2026 at 07:16:03PM +0200, Pavol Sakac wrote:
> kernfs_add_one() links a new node, releases kernfs_rwsem, and takes it
> again through kernfs_activate(). A new node has no descendants, so the
> second hold only activates that node.
>
> Activate ordinary nodes before releasing the linking hold, removing a
> second write-side acquisition and the linked-but-inactive interval.
> KERNFS_ROOT_CREATE_DEACTIVATED roots retain explicit subtree activation.
>
> Removing the unlock-to-lock pair also removes its publication ordering.
> The in-tree lockless ID lookups use CREATE_DEACTIVATED roots and retain
> kernfs_activate(); unsynchronized callers cannot rely on observing a
> node.
...
> +static void kernfs_activate_one(struct kernfs_node *kn);
> +
Can we avoid adding forward declarations like this? Or is there circular
dependencies? If not, add another patch that simply moves the existing code
upper, so this patch won't need a forward declaration.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-09-11 18:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-11 17:16 [PATCH 0/3] kernfs, driver core: Cut per-node lock traffic in bulk registration Pavol Sakac
2026-09-11 17:16 ` [PATCH 1/3] kernfs: activate nodes while linking them Pavol Sakac
2026-09-11 18:12 ` Andy Shevchenko [this message]
2026-09-11 17:16 ` [PATCH 2/3] driver core: Index class glue directories by parent kobject Pavol Sakac
2026-09-11 18:11 ` Andy Shevchenko
2026-09-11 17:16 ` [PATCH 3/3] kernfs: batch inode ID allocation per CPU Pavol Sakac
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