From: Tejun Heo <tj@kernel.org>
To: Imran Khan <imran.f.khan@oracle.com>
Cc: viro@zeniv.linux.org.uk, gregkh@linuxfoundation.org,
ebiederm@xmission.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 03/10] kernfs: Change kernfs_notify_list to llist.
Date: Fri, 22 Apr 2022 06:41:45 -1000 [thread overview]
Message-ID: <YmLaySAIldwNwreD@slm.duckdns.org> (raw)
In-Reply-To: <20220410023719.1752460-4-imran.f.khan@oracle.com>
Hello,
On Sun, Apr 10, 2022 at 12:37:12PM +1000, Imran Khan wrote:
> @@ -846,18 +845,25 @@ static void kernfs_notify_workfn(struct work_struct *work)
> struct kernfs_node *kn;
> struct kernfs_super_info *info;
> struct kernfs_root *root;
> + struct llist_node *free;
> + struct kernfs_elem_attr *attr;
> repeat:
> - /* pop one off the notify_list */
> + /**
> + * pop one off the notify_list.
> + * There can be multiple concurrent work items.
> + * Use kernfs_notify_lock to synchronize between multipl consumers.
> + */
This is running off of a single work item, so there can only be one instance
of this running at any given time.
> spin_lock_irq(&kernfs_notify_lock);
> - kn = kernfs_notify_list;
> - if (kn == KERNFS_NOTIFY_EOL) {
> + if (llist_empty(&kernfs_notify_list)) {
> spin_unlock_irq(&kernfs_notify_lock);
> return;
> }
> - kernfs_notify_list = kn->attr.notify_next;
> - kn->attr.notify_next = NULL;
> +
> + free = llist_del_first(&kernfs_notify_list);
Why not just test whether the returned pointer is NULL here instead of doing
a separate empty check above?
Thanks.
--
tejun
next prev parent reply other threads:[~2022-04-22 16:41 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
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 [this message]
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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