Commit c011bb66 authored by Mike Christie's avatar Mike Christie Committed by Michael S. Tsirkin
Browse files

vhost: dynamically allocate vhost_worker 



This patchset allows us to allocate multiple workers, so this has us
move from the vhost_worker that's embedded in the vhost_dev to
dynamically allocating it.

Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Message-Id: <20230626232307.97930-3-michael.christie@oracle.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 3e11c6eb

drivers/vhost/vhost.c

+43 −23
Original line number Diff line number Diff line
@@ -235,36 +235,40 @@ void vhost_dev_flush(struct vhost_dev *dev) 
{

	struct vhost_flush_struct flush;



	if (dev->worker.vtsk) {

	init_completion(&flush.wait_event);

	vhost_work_init(&flush.work, vhost_flush_work);



		vhost_work_queue(dev, &flush.work);

	if (vhost_work_queue(dev, &flush.work))

		wait_for_completion(&flush.wait_event);

}

}

EXPORT_SYMBOL_GPL(vhost_dev_flush);



void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)

bool vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)

{

	if (!dev->worker.vtsk)

		return;



	if (!dev->worker)

		return false;

	/*

	 * vsock can queue while we do a VHOST_SET_OWNER, so we have a smp_wmb

	 * when setting up the worker. We don't have a smp_rmb here because

	 * test_and_set_bit gives us a mb already.

	 */

	if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {

		/* We can only add the work to the list after we're

		 * sure it was not in the list.

		 * test_and_set_bit() implies a memory barrier.

		 */

		llist_add(&work->node, &dev->worker.work_list);

		vhost_task_wake(dev->worker.vtsk);

		llist_add(&work->node, &dev->worker->work_list);

		vhost_task_wake(dev->worker->vtsk);

	}



	return true;

}

EXPORT_SYMBOL_GPL(vhost_work_queue);



/* A lockless hint for busy polling code to exit the loop */

bool vhost_has_work(struct vhost_dev *dev)

{

	return !llist_empty(&dev->worker.work_list);

	return !llist_empty(&dev->worker->work_list);

}

EXPORT_SYMBOL_GPL(vhost_has_work);
@@ -458,8 +462,7 @@ void vhost_dev_init(struct vhost_dev *dev, 
	dev->umem = NULL;

	dev->iotlb = NULL;

	dev->mm = NULL;

	memset(&dev->worker, 0, sizeof(dev->worker));

	init_llist_head(&dev->worker.work_list);

	dev->worker = NULL;

	dev->iov_limit = iov_limit;

	dev->weight = weight;

	dev->byte_weight = byte_weight;
@@ -533,30 +536,47 @@ static void vhost_detach_mm(struct vhost_dev *dev) 


static void vhost_worker_free(struct vhost_dev *dev)

{

	if (!dev->worker.vtsk)

	if (!dev->worker)

		return;



	WARN_ON(!llist_empty(&dev->worker.work_list));

	vhost_task_stop(dev->worker.vtsk);

	dev->worker.kcov_handle = 0;

	dev->worker.vtsk = NULL;

	WARN_ON(!llist_empty(&dev->worker->work_list));

	vhost_task_stop(dev->worker->vtsk);

	kfree(dev->worker);

	dev->worker = NULL;

}



static int vhost_worker_create(struct vhost_dev *dev)

{

	struct vhost_worker *worker;

	struct vhost_task *vtsk;

	char name[TASK_COMM_LEN];



	worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);

	if (!worker)

		return -ENOMEM;



	snprintf(name, sizeof(name), "vhost-%d", current->pid);



	vtsk = vhost_task_create(vhost_worker, &dev->worker, name);

	vtsk = vhost_task_create(vhost_worker, worker, name);

	if (!vtsk)

		return -ENOMEM;

		goto free_worker;



	init_llist_head(&worker->work_list);

	worker->kcov_handle = kcov_common_handle();

	worker->vtsk = vtsk;

	/*

	 * vsock can already try to queue so make sure llist and vtsk are both

	 * set before vhost_work_queue sees dev->worker is set.

	 */

	smp_wmb();

	dev->worker = worker;



	dev->worker.kcov_handle = kcov_common_handle();

	dev->worker.vtsk = vtsk;

	vhost_task_start(vtsk);

	return 0;



free_worker:

	kfree(worker);

	return -ENOMEM;

}



/* Caller should have device mutex */

drivers/vhost/vhost.h

+2 −2
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ struct vhost_poll { 
};



void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);

void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);

bool vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);

bool vhost_has_work(struct vhost_dev *dev);



void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
@@ -158,7 +158,7 @@ struct vhost_dev { 
	struct vhost_virtqueue **vqs;

	int nvqs;

	struct eventfd_ctx *log_ctx;

	struct vhost_worker worker;

	struct vhost_worker *worker;

	struct vhost_iotlb *umem;

	struct vhost_iotlb *iotlb;

	spinlock_t iotlb_lock;