Unverified Commit 1a5f8090 authored by Mike Christie's avatar Mike Christie Committed by Christian Brauner
Browse files

vhost: move worker thread fields to new struct 



This is just a prep patch. It moves the worker related fields to a new
vhost_worker struct and moves the code around to create some helpers that
will be used in the next patch.

Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent e297cd54

drivers/vhost/vhost.c

+64 −34
Original line number Diff line number Diff line
@@ -255,8 +255,8 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) 
		 * sure it was not in the list.

		 * test_and_set_bit() implies a memory barrier.

		 */

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

		wake_up_process(dev->worker);

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

		wake_up_process(dev->worker->task);

	}

}

EXPORT_SYMBOL_GPL(vhost_work_queue);
@@ -264,7 +264,7 @@ 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->work_list);

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

}

EXPORT_SYMBOL_GPL(vhost_has_work);
@@ -335,7 +335,8 @@ static void vhost_vq_reset(struct vhost_dev *dev, 


static int vhost_worker(void *data)

{

	struct vhost_dev *dev = data;

	struct vhost_worker *worker = data;

	struct vhost_dev *dev = worker->dev;

	struct vhost_work *work, *work_next;

	struct llist_node *node;
@@ -350,7 +351,7 @@ static int vhost_worker(void *data) 
			break;

		}



		node = llist_del_all(&dev->work_list);

		node = llist_del_all(&worker->work_list);

		if (!node)

			schedule();
@@ -360,7 +361,7 @@ static int vhost_worker(void *data) 
		llist_for_each_entry_safe(work, work_next, node, node) {

			clear_bit(VHOST_WORK_QUEUED, &work->flags);

			__set_current_state(TASK_RUNNING);

			kcov_remote_start_common(dev->kcov_handle);

			kcov_remote_start_common(worker->kcov_handle);

			work->fn(work);

			kcov_remote_stop();

			if (need_resched())
@@ -479,7 +480,6 @@ void vhost_dev_init(struct vhost_dev *dev, 
	dev->byte_weight = byte_weight;

	dev->use_worker = use_worker;

	dev->msg_handler = msg_handler;

	init_llist_head(&dev->work_list);

	init_waitqueue_head(&dev->wait);

	INIT_LIST_HEAD(&dev->read_list);

	INIT_LIST_HEAD(&dev->pending_list);
@@ -571,10 +571,60 @@ static void vhost_detach_mm(struct vhost_dev *dev) 
	dev->mm = NULL;

}



static void vhost_worker_free(struct vhost_dev *dev)

{

	struct vhost_worker *worker = dev->worker;



	if (!worker)

		return;



	dev->worker = NULL;

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

	kthread_stop(worker->task);

	kfree(worker);

}



static int vhost_worker_create(struct vhost_dev *dev)

{

	struct vhost_worker *worker;

	struct task_struct *task;

	int ret;



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

	if (!worker)

		return -ENOMEM;



	dev->worker = worker;

	worker->dev = dev;

	worker->kcov_handle = kcov_common_handle();

	init_llist_head(&worker->work_list);



	task = kthread_create(vhost_worker, worker, "vhost-%d", current->pid);

	if (IS_ERR(task)) {

		ret = PTR_ERR(task);

		goto free_worker;

	}



	worker->task = task;

	wake_up_process(task); /* avoid contributing to loadavg */



	ret = vhost_attach_cgroups(dev);

	if (ret)

		goto stop_worker;



	return 0;



stop_worker:

	kthread_stop(worker->task);

free_worker:

	kfree(worker);

	dev->worker = NULL;

	return ret;

}



/* Caller should have device mutex */

long vhost_dev_set_owner(struct vhost_dev *dev)

{

	struct task_struct *worker;

	int err;



	/* Is there an owner already? */
@@ -585,36 +635,21 @@ long vhost_dev_set_owner(struct vhost_dev *dev) 


	vhost_attach_mm(dev);



	dev->kcov_handle = kcov_common_handle();

	if (dev->use_worker) {

		worker = kthread_create(vhost_worker, dev,

					"vhost-%d", current->pid);

		if (IS_ERR(worker)) {

			err = PTR_ERR(worker);

			goto err_worker;

		}



		dev->worker = worker;

		wake_up_process(worker); /* avoid contributing to loadavg */



		err = vhost_attach_cgroups(dev);

		err = vhost_worker_create(dev);

		if (err)

			goto err_cgroup;

			goto err_worker;

	}



	err = vhost_dev_alloc_iovecs(dev);

	if (err)

		goto err_cgroup;

		goto err_iovecs;



	return 0;

err_cgroup:

	if (dev->worker) {

		kthread_stop(dev->worker);

		dev->worker = NULL;

	}

err_iovecs:

	vhost_worker_free(dev);

err_worker:

	vhost_detach_mm(dev);

	dev->kcov_handle = 0;

err_mm:

	return err;

}
@@ -705,12 +740,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) 
	dev->iotlb = NULL;

	vhost_clear_msg(dev);

	wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);

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

	if (dev->worker) {

		kthread_stop(dev->worker);

		dev->worker = NULL;

		dev->kcov_handle = 0;

	}

	vhost_worker_free(dev);

	vhost_detach_mm(dev);

}

EXPORT_SYMBOL_GPL(vhost_dev_cleanup);

drivers/vhost/vhost.h

+8 −3
Original line number Diff line number Diff line
@@ -25,6 +25,13 @@ struct vhost_work { 
	unsigned long		flags;

};



struct vhost_worker {

	struct task_struct	*task;

	struct llist_head	work_list;

	struct vhost_dev	*dev;

	u64			kcov_handle;

};



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

/* Note: there's nothing vhost specific about this structure. */

struct vhost_poll {
@@ -147,8 +154,7 @@ struct vhost_dev { 
	struct vhost_virtqueue **vqs;

	int nvqs;

	struct eventfd_ctx *log_ctx;

	struct llist_head work_list;

	struct task_struct *worker;

	struct vhost_worker *worker;

	struct vhost_iotlb *umem;

	struct vhost_iotlb *iotlb;

	spinlock_t iotlb_lock;
@@ -158,7 +164,6 @@ struct vhost_dev { 
	int iov_limit;

	int weight;

	int byte_weight;

	u64 kcov_handle;

	bool use_worker;

	int (*msg_handler)(struct vhost_dev *dev, u32 asid,

			   struct vhost_iotlb_msg *msg);