[PATCH v8 03/17] vhost: add vhost_worker pointer to vhost_virtqueue

Mike Christie
Tue, 13 Jun 2023 01:32:34 -0000

This patchset allows userspace to map vqs to different workers. This
patch adds a worker pointer to the vq so in later patches in this set
we can queue/flush specific vqs and their workers.

Signed-off-by: Mike Christie <michael.christie at oracle.com>
---
 drivers/vhost/vhost.c | 21 ++++++++++++++-------
 drivers/vhost/vhost.h |  1 +
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index dfd96cf6a152..c78c15af97d3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -479,6 +479,7 @@ void vhost_dev_init(struct vhost_dev *dev,
 		vq->log = NULL;
 		vq->indirect = NULL;
 		vq->heads = NULL;
+		vq->worker = NULL;
 		vq->dev = dev;
 		mutex_init(&vq->mutex);
 		vhost_vq_reset(dev, vq);
@@ -545,7 +546,7 @@ static void vhost_worker_free(struct vhost_dev *dev)
 	dev->worker = NULL;
 }

-static int vhost_worker_create(struct vhost_dev *dev)
+static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
 {
 	struct vhost_worker *worker;
 	struct vhost_task *vtsk;
@@ -553,7 +554,7 @@ static int vhost_worker_create(struct vhost_dev *dev)

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

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

@@ -572,17 +573,18 @@ static int vhost_worker_create(struct vhost_dev *dev)
 	dev->worker = worker;

 	vhost_task_start(vtsk);
-	return 0;
+	return worker;

 free_worker:
 	kfree(worker);
-	return -ENOMEM;
+	return NULL;
 }

 /* Caller should have device mutex */
 long vhost_dev_set_owner(struct vhost_dev *dev)
 {
-	int err;
+	struct vhost_worker *worker;
+	int err, i;

 	/* Is there an owner already? */
 	if (vhost_dev_has_owner(dev)) {
@@ -603,9 +605,14 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
 		 * below since we don't have to worry about vsock queueing
 		 * while we free the worker.
 		 */
-		err = vhost_worker_create(dev);
-		if (err)
+		worker = vhost_worker_create(dev);
+		if (!worker) {
+			err = -ENOMEM;
 			goto err_worker;
+		}
+
+		for (i = 0; i < dev->nvqs; i++)
+			dev->vqs[i]->worker = worker;
 	}

 	return 0;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index cb872cc4157a..206617edb2a9 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -74,6 +74,7 @@ struct vhost_vring_call {
 /* The virtqueue structure describes a queue attached to a device. */
 struct vhost_virtqueue {
 	struct vhost_dev *dev;
+	struct vhost_worker *worker;

 	/* The actual ring of buffers. */
 	struct mutex mutex;
--
2.25.1