[RESEND PATCH v1 3/7] vhost: Add kthread support in function vhost_workers_free()

Cindy Lu
2024-09-09T02:02:12Z

Added back the previously removed function vhost_workers_free() and
renamed it to vhost_workers_free_khtread(). The new vhost_workers_free()
will select the different mode based on the value of the parameter.

The old function vhost_workers_free was change to support task in
commit 6e890c5d5021 ('vhost: use vhost_tasks for worker threads')
also changed in
commit a284f09effe ('vhost: Fix crash during early vhost_transport_send_pkt calls')
change to xarray in
commit 1cdaafa1b8b ('vhost: replace single worker pointer with xarray')

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
drivers/vhost/vhost.c | 52 ++++++++++++++++++++++++++++++++++++++-----
1 file changed, 47 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index ab4608fcf86b..da4482efd2cb 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -647,8 +647,21 @@ static void vhost_detach_mm(struct vhost_dev *dev)
dev->mm = NULL;
}

-static void vhost_worker_destroy(struct vhost_dev *dev,
- struct vhost_worker *worker)
+static void vhost_worker_destroy_kthread(struct vhost_dev *dev,
+ struct vhost_worker *worker)
+{
+ if (!worker)
+ return;
+
+ WARN_ON(!llist_empty(&worker->work_list));
+
+ xa_erase(&dev->worker_xa, worker->id);
+ kthread_stop(worker->task);
+ kfree(worker);
+}
+
+static void vhost_worker_destroy_task(struct vhost_dev *dev,
+ struct vhost_worker *worker)
{
if (!worker)
return;
@@ -659,7 +672,7 @@ static void vhost_worker_destroy(struct vhost_dev *dev,
kfree(worker);
}

-static void vhost_workers_free(struct vhost_dev *dev)
+static void vhost_workers_free_task(struct vhost_dev *dev)
{
struct vhost_worker *worker;
unsigned long i;
@@ -674,10 +687,36 @@ static void vhost_workers_free(struct vhost_dev *dev)
* created but couldn't clean up (it forgot or crashed).
*/
xa_for_each(&dev->worker_xa, i, worker)
- vhost_worker_destroy(dev, worker);
+ vhost_worker_destroy_task(dev, worker);
xa_destroy(&dev->worker_xa);
}

+static void vhost_workers_free_kthread(struct vhost_dev *dev)
+{
+ struct vhost_worker *worker;
+ unsigned long i;
+
+ if (!dev->use_worker)
+ return;
+
+ for (i = 0; i < dev->nvqs; i++)
+ rcu_assign_pointer(dev->vqs[i]->worker, NULL);
+ /*
+ * Free the default worker we created and cleanup workers userspace
+ * created but couldn't clean up (it forgot or crashed).
+ */
+ xa_for_each(&dev->worker_xa, i, worker)
+ vhost_worker_destroy_kthread(dev, worker);
+ xa_destroy(&dev->worker_xa);
+}
+
+static void vhost_workers_free(struct vhost_dev *dev)
+{
+ if (enforce_kthread)
+ vhost_workers_free_kthread(dev);
+ else
+ vhost_workers_free_task(dev);
+}
static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
{
struct vhost_worker *worker;
@@ -845,7 +884,10 @@ static int vhost_free_worker(struct vhost_dev *dev,
__vhost_worker_flush(worker);
mutex_unlock(&worker->mutex);

- vhost_worker_destroy(dev, worker);
+ if (enforce_kthread)
+ vhost_worker_destroy_kthread(dev, worker);
+ else
+ vhost_worker_destroy_task(dev, worker);
return 0;
}

--
2.45.0