This commit restores the previously removed functions kthread_wakeup and
kthread_stop, and introduces a new ops structure to handle worker wakeup,
stop, and creation. The function vhost_worker_create initializes these
ops pointers based on the inherit_owner value.
Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 115 +++++++++++++++++++++++++++++++++++-------
drivers/vhost/vhost.h | 12 +++++
2 files changed, 110 insertions(+), 17 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index adbb957c8b5f..d8c0ea118bb1 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);
}
}
@@ -697,7 +697,7 @@ 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);
}
@@ -720,42 +720,123 @@ static void vhost_workers_free(struct vhost_dev *dev)
xa_destroy(&dev->worker_xa);
}
+static void vhost_task_wakeup_fn(struct vhost_worker *worker)
+{
+ return vhost_task_wake(worker->vtsk);
+}
+
+static void vhost_kthread_wakeup_fn(struct vhost_worker *worker)
+{
+ wake_up_process(worker->kthread_task);
+}
+
+static void vhost_task_stop_fn(struct vhost_worker *worker)
+{
+ return vhost_task_stop(worker->vtsk);
+}
+
+static void vhost_kthread_stop_fn(struct vhost_worker *worker)
+{
+ kthread_stop(worker->kthread_task);
+}
+
+static int vhost_task_worker_create_fn(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 (!vtsk)
+ return -ENOMEM;
+
+ 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_stop_fn(worker);
+ return ret;
+ }
+ worker->id = id;
+ return 0;
+}
+
+static int kthread_worker_create_fn(struct vhost_worker *worker,
+ struct vhost_dev *dev, const char *name)
+{
+ struct task_struct *task;
+ u32 id;
+ int ret;
+
+ task = kthread_create(vhost_run_work_kthread_list, worker, "%s", name);
+ if (IS_ERR(task))
+ return PTR_ERR(task);
+
+ worker->kthread_task = task;
+ wake_up_process(task);
+ ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ if (ret < 0)
+ goto stop_worker;
+
+ ret = vhost_attach_task_to_cgroups(worker);
+ if (ret)
+ goto stop_worker;
+
+ worker->id = id;
+ return 0;
+
+stop_worker:
+ vhost_kthread_stop_fn(worker);
+ return ret;
+}
+
+static const struct vhost_worker_ops vhost_task_ops = {
+ .create = vhost_task_worker_create_fn,
+ .stop = vhost_task_stop_fn,
+ .wakeup = vhost_task_wakeup_fn,
+};
+
+static const struct vhost_worker_ops kthread_ops = {
+ .create = kthread_worker_create_fn,
+ .stop = vhost_kthread_stop_fn,
+ .wakeup = vhost_kthread_wakeup_fn,
+};
+
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 =
+ dev->inherit_owner ? &vhost_task_ops : &kthread_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 (!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 inherit_owner is true we use vhost_tasks to create
+ * the worker so all settings/limits like cgroups, NPROC,
+ * scheduler, etc are inherited from the owner. If false,
+ * we use kthreads and only attach to the same cgroups
+ * as the owner for compat with older kernels.
+ */
- 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 c650c4506c70..029c203147be 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -26,7 +26,18 @@ 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 task_struct *kthread_task;
struct vhost_task *vtsk;
struct vhost_dev *dev;
/* Used to serialize device wide flushing with worker swapping. */
@@ -36,6 +47,7 @@ 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
