From: Tejun Heo <tj@kernel.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Imran Khan <imran.f.khan@oracle.com>,
gregkh@linuxfoundation.org, ebiederm@xmission.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 01/10] kernfs: Remove reference counting for kernfs_open_node.
Date: Tue, 26 Apr 2022 10:16:21 -1000 [thread overview]
Message-ID: <YmhTFZ5zCGhWJOry@slm.duckdns.org> (raw)
In-Reply-To: <YmhSYkXp0KBXOyFc@zeniv-ca.linux.org.uk>
On Tue, Apr 26, 2022 at 08:13:22PM +0000, Al Viro wrote:
> On Tue, Apr 26, 2022 at 08:29:21AM -1000, Tejun Heo wrote:
>
> > The code is just wrong. You can end up:
> >
> > on = kn->attr.open;
> > if (!on)
> > return;
> >
> > // we get preempted here and someone else puts @on and then
> > // recreates it
>
> Can't happen - the caller has guaranteed that no new openers will be
> coming. Look at the call chain of kernfs_drain_open_files()...
Ah, okay. It can only transition to NULL from there. It's still a weird way
to go about it tho.
Thanks.
--
tejun
next prev parent reply other threads:[~2022-04-26 20:17 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-10 2:37 [PATCH v8 00/10] kernfs: Remove reference counting for kernfs_open_node Imran Khan
2022-04-10 2:37 ` [PATCH v8 01/10] " Imran Khan
2022-04-22 16:03 ` Tejun Heo
2022-04-26 1:43 ` Imran Khan
2022-04-26 18:29 ` Tejun Heo
2022-04-26 20:13 ` Al Viro
2022-04-26 20:16 ` Tejun Heo [this message]
2022-04-10 2:37 ` [PATCH v8 02/10] kernfs: make ->attr.open RCU protected Imran Khan
2022-04-22 16:19 ` Tejun Heo
2022-04-26 1:54 ` Imran Khan
2022-04-26 18:37 ` Tejun Heo
2022-04-10 2:37 ` [PATCH v8 03/10] kernfs: Change kernfs_notify_list to llist Imran Khan
2022-04-22 16:41 ` Tejun Heo
2022-04-10 2:37 ` [PATCH v8 04/10] kernfs: Introduce interface to access global kernfs_open_file_mutex Imran Khan
2022-04-10 2:37 ` [PATCH v8 05/10] kernfs: Replace global kernfs_open_file_mutex with hashed mutexes Imran Khan
2022-04-22 17:00 ` Tejun Heo
2022-04-10 2:37 ` [PATCH v8 06/10] kernfs: Use a per-fs rwsem to protect per-fs list of kernfs_super_info Imran Khan
2022-04-10 2:37 ` [PATCH v8 07/10] kernfs: Change kernfs_rename_lock into a read-write lock Imran Khan
2022-04-10 2:37 ` [PATCH v8 08/10] kernfs: Introduce interface to access per-fs rwsem Imran Khan
2022-04-10 2:37 ` [PATCH v8 09/10] kernfs: Replace per-fs rwsem with hashed rwsems Imran Khan
2022-04-10 2:37 ` [PATCH v8 10/10] kernfs: Add a document to describe hashed locks used in kernfs Imran Khan
2022-04-22 17:03 ` [PATCH v8 00/10] kernfs: Remove reference counting for kernfs_open_node Tejun Heo
2022-04-23 8:49 ` Imran Khan
2022-04-25 17:21 ` Tejun Heo
2022-04-28 17:28 ` Imran Khan
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