Re: [PATCH] vhost: use kthread_run macro
From: Michael S. Tsirkin
Date: Wed Apr 15 2015 - 05:59:14 EST
On Tue, Apr 14, 2015 at 05:32:34PM -0400, Bandan Das wrote:
>
> Code Cleanup, kthread_run is a convenient wrapper
> around kthread_create() that even wakes up the process
> for us. Use it and remove no longer needed temp
> task_struct variable.
>
> Signed-off-by: Bandan Das <bsd@xxxxxxxxxx>
> ---
> drivers/vhost/vhost.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 2ee2826..9ac66f7 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -366,7 +366,6 @@ EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
> /* Caller should have device mutex */
> long vhost_dev_set_owner(struct vhost_dev *dev)
> {
> - struct task_struct *worker;
> int err;
>
> /* Is there an owner already? */
> @@ -377,15 +376,12 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
>
> /* No owner, become one */
> dev->mm = get_task_mm(current);
> - worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
> - if (IS_ERR(worker)) {
> - err = PTR_ERR(worker);
> + dev->worker = kthread_run(vhost_worker, dev, "vhost-%d", current->pid);
> + if (IS_ERR(dev->worker)) {
> + err = PTR_ERR(dev->worker);
> goto err_worker;
If you do it like this, dev->worker is not initialized when thread
starts running. As thread itself might queue entries using
vhost_work_queue, this seems wrong.
> }
>
> - dev->worker = worker;
> - wake_up_process(worker); /* avoid contributing to loadavg */
> -
> err = vhost_attach_cgroups(dev);
> if (err)
> goto err_cgroup;
> @@ -396,7 +392,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
>
> return 0;
> err_cgroup:
> - kthread_stop(worker);
> + kthread_stop(dev->worker);
> dev->worker = NULL;
> err_worker:
> if (dev->mm)
> --
> 2.1.0
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