[PATCH v4 08/14] virtio_ring: queue_reset: add vring_release_virtqueue()

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

Added vring_release_virtqueue() to release the ring of the vq.

In this process, vq is removed from the vdev->vqs queue. And the memory
of the ring is released

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 13 ++++++++++++-
 include/linux/virtio.h       |  5 +++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index f5e5fec6d904..b8747df8dc1f 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2363,6 +2363,8 @@ static void __vring_del_virtqueue(struct vring_virtqueue *vq)
 	list_del(&vq->vq.list);
 	spin_unlock(&vq->vq.vdev->vqs_list_lock);
 
+	INIT_LIST_HEAD(&vq->vq.list);
+
 	if (vq->we_own_ring) {
 		if (vq->packed_ring) {
 			vring_free_queue(vq->vq.vdev,
@@ -2399,11 +2401,20 @@ void vring_del_virtqueue(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
-	__vring_del_virtqueue(vq);
+	if (!list_empty(&vq->vq.list))
+		__vring_del_virtqueue(vq);
 	kfree(vq);
 }
 EXPORT_SYMBOL_GPL(vring_del_virtqueue);
 
+void vring_release_virtqueue(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	__vring_del_virtqueue(vq);
+}
+EXPORT_SYMBOL_GPL(vring_release_virtqueue);
+
 /* Manipulates transport-specific feature bits. */
 void vring_transport_features(struct virtio_device *vdev)
 {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 41edbc01ffa4..dd1657c3a488 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -195,4 +195,9 @@ void unregister_virtio_driver(struct virtio_driver *drv);
 #define module_virtio_driver(__virtio_driver) \
 	module_driver(__virtio_driver, register_virtio_driver, \
 			unregister_virtio_driver)
+/*
+ * Resets a virtqueue. Just frees the ring, not free vq.
+ * This function must be called after reset_vq().
+ */
+void vring_release_virtqueue(struct virtqueue *vq);
 #endif /* _LINUX_VIRTIO_H */
-- 
2.31.0

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