On Tue, Nov 5, 2024 at 3:27 PM Cindy Lu <lulu@xxxxxxxxxx> wrote:
>
> Restored the previous functions kthread_wakeup and kthread_stop.
> Also add a new structure, vhost_task_fn. The function vhost_worker_create
> Will initializes this structure based on the value of inherit_owner.
>
> Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
> ---
> drivers/vhost/vhost.c | 71 ++++++++++++++++++++++++++++++++++++-------
> drivers/vhost/vhost.h | 6 ++++
> 2 files changed, 66 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index e40cef3a1fa5..603b146fccc1 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -741,43 +741,92 @@ static void vhost_workers_free(struct vhost_dev *dev)
> xa_destroy(&dev->worker_xa);
> }
>
> +static int vhost_task_wakeup_fn(void *vtsk)
> +{
> + vhost_task_wake((struct vhost_task *)vtsk);
> + return 0;
> +}
Let's have a newline between two functions.
> +static int vhost_kthread_wakeup_fn(void *p)
> +{
> + return wake_up_process((struct task_struct *)p);
> +}
> +static int vhost_task_stop_fn(void *vtsk)
> +{
> + vhost_task_stop((struct vhost_task *)vtsk);
> + return 0;
> +}
> +static int vhost_kthread_stop_fn(void *k)
> +{
> + return kthread_stop((struct task_struct *)k);
> +}
> +
> static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
> {
> struct vhost_worker *worker;
> - struct vhost_task *vtsk;
> + struct vhost_task *vtsk = NULL;
> + struct task_struct *task = NULL;
> char name[TASK_COMM_LEN];
> int ret;
> u32 id;
>
> + /* Allocate resources for the worker */
> worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
> if (!worker)
> return NULL;
>
> + worker->fn = kzalloc(sizeof(struct vhost_task_fn), GFP_KERNEL_ACCOUNT);
> + if (!worker->fn) {
> + kfree(worker);
> + return NULL;
> + }
> +
> worker->dev = dev;
> snprintf(name, sizeof(name), "vhost-%d", current->pid);
>
> - vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
> - worker, name);
> - if (!vtsk)
> - goto free_worker;
> -
> mutex_init(&worker->mutex);
> init_llist_head(&worker->work_list);
> worker->kcov_handle = kcov_common_handle();
> - worker->vtsk = vtsk;
>
> - vhost_task_start(vtsk);
> + if (dev->inherit_owner) {
> + /* Create and start a vhost task */
> + vtsk = vhost_task_create(vhost_run_work_list,
> + vhost_worker_killed, worker, name);
> + if (!vtsk)
> + goto free_worker;
> +
> + worker->vtsk = vtsk;
> + worker->fn->wakeup = vhost_task_wakeup_fn;
> + worker->fn->stop = vhost_task_stop_fn;
> +
> + vhost_task_start(vtsk);
> + } else {
> + /* Create and start a kernel thread */
> + task = kthread_create(vhost_run_work_kthread_list, worker,
> + "vhost-%d", current->pid);
> + if (IS_ERR(task)) {
> + ret = PTR_ERR(task);
> + goto free_worker;
> + }
> + worker->task = task;
> + worker->fn->wakeup = vhost_kthread_wakeup_fn;
> + worker->fn->stop = vhost_kthread_stop_fn;
> +
> + wake_up_process(task);
> + /* Attach to the vhost cgroup */
> + ret = vhost_attach_cgroups(dev);
> + if (ret)
> + goto stop_worker;
> + }
>
> ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
> if (ret < 0)
> goto stop_worker;
> worker->id = id;
> -
> return worker;
> -
> stop_worker:
> - vhost_task_stop(vtsk);
> + worker->fn->stop(dev->inherit_owner ? (void *)vtsk : (void *)task);
> free_worker:
> + kfree(worker->fn);
> kfree(worker);
> return NULL;
> }
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index c650c4506c70..ebababa4e340 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -25,8 +25,13 @@ struct vhost_work {
> vhost_work_fn_t fn;
> unsigned long flags;
> };
> +struct vhost_task_fn {
> + int (*wakeup)(void *task);
Let's have comments to explain the semantics of each operation.
> + int (*stop)(void *task);
> +};
I think the goal is to reduce if/else, so while at this, let's
introduce more ops. For example the create_worker one?
>
> struct vhost_worker {
> + struct task_struct *task;
> struct vhost_task *vtsk;
> struct vhost_dev *dev;
> /* Used to serialize device wide flushing with worker swapping. */
> @@ -36,6 +41,7 @@ struct vhost_worker {
> u32 id;
> int attachment_cnt;
> bool killed;
> + struct vhost_task_fn *fn;
> };
>
> /* Poll a file (eventfd or socket) */
> --
> 2.45.0
>
Thanks
