[PATCH v8 4/8] vhost: Introduce vhost_worker_ops in vhost_worker

Cindy Lu
2025-03-28T10:04:59Z

Abstract vhost worker operations (create/stop/wakeup) into an ops
structure to prepare for kthread mode support.

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
drivers/vhost/vhost.c | 63 ++++++++++++++++++++++++++++++-------------
drivers/vhost/vhost.h | 11 ++++++++
2 files changed, 56 insertions(+), 18 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 20571bd6f7bd..c162ad772f8f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -243,7 +243,7 @@ static void vhost_worker_queue(struct vhost_worker *worker,
* test_and_set_bit() implies a memory barrier.
*/
llist_add(&work->node, &worker->work_list);
- vhost_task_wake(worker->vtsk);
+ worker->ops->wakeup(worker);
}
}

@@ -706,7 +706,7 @@ static void vhost_worker_destroy(struct vhost_dev *dev,

WARN_ON(!llist_empty(&worker->work_list));
xa_erase(&dev->worker_xa, worker->id);
- vhost_task_stop(worker->vtsk);
+ worker->ops->stop(worker);
kfree(worker);
}

@@ -729,42 +729,69 @@ static void vhost_workers_free(struct vhost_dev *dev)
xa_destroy(&dev->worker_xa);
}

+static void vhost_task_wakeup(struct vhost_worker *worker)
+{
+ return vhost_task_wake(worker->vtsk);
+}
+
+static void vhost_task_do_stop(struct vhost_worker *worker)
+{
+ return vhost_task_stop(worker->vtsk);
+}
+
+static int vhost_task_worker_create(struct vhost_worker *worker,
+ struct vhost_dev *dev, const char *name)
+{
+ struct vhost_task *vtsk;
+ u32 id;
+ int ret;
+
+ vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
+ worker, name);
+ if (IS_ERR(vtsk))
+ return PTR_ERR(vtsk);
+
+ worker->vtsk = vtsk;
+ vhost_task_start(vtsk);
+ ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ if (ret < 0) {
+ vhost_task_do_stop(worker);
+ return ret;
+ }
+ worker->id = id;
+ return 0;
+}
+
+static const struct vhost_worker_ops vhost_task_ops = {
+ .create = vhost_task_worker_create,
+ .stop = vhost_task_do_stop,
+ .wakeup = vhost_task_wakeup,
+};
+
static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
{
struct vhost_worker *worker;
- struct vhost_task *vtsk;
char name[TASK_COMM_LEN];
int ret;
- u32 id;
+ const struct vhost_worker_ops *ops = &vhost_task_ops;

worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
if (!worker)
return NULL;

worker->dev = dev;
+ worker->ops = ops;
snprintf(name, sizeof(name), "vhost-%d", current->pid);

- vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
- worker, name);
- if (IS_ERR(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);
-
- ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ ret = ops->create(worker, dev, name);
if (ret < 0)
- goto stop_worker;
- worker->id = id;
+ goto free_worker;

return worker;

-stop_worker:
- vhost_task_stop(vtsk);
free_worker:
kfree(worker);
return NULL;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 19bb94922a0e..98895e299efa 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -26,6 +26,16 @@ struct vhost_work {
unsigned long flags;
};

+struct vhost_worker;
+struct vhost_dev;
+
+struct vhost_worker_ops {
+ int (*create)(struct vhost_worker *worker, struct vhost_dev *dev,
+ const char *name);
+ void (*stop)(struct vhost_worker *worker);
+ void (*wakeup)(struct vhost_worker *worker);
+};
+
struct vhost_worker {
struct vhost_task *vtsk;
struct vhost_dev *dev;
@@ -36,6 +46,7 @@ struct vhost_worker {
u32 id;
int attachment_cnt;
bool killed;
+ const struct vhost_worker_ops *ops;
};

/* Poll a file (eventfd or socket) */
--
2.45.0