virtio/s390: use vring_create_virtqueue

The commit 2a2d1382fe9d ("virtio: Add improved queue allocation API")
establishes a new way of allocating virtqueues (as a part of the effort
that taught DMA to virtio rings).

In the future we will want virtio-ccw to use the DMA API as well.

Let us switch from the legacy method of allocating virtqueues to
vring_create_virtqueue() as the first step into that direction.

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 11 insertions, 19 deletions

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 74c328321889..2c66941ef3d0 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -108,7 +108,6 @@ struct virtio_rev_info {
 struct virtio_ccw_vq_info {
         struct virtqueue *vq;
         int num;
-        void *queue;
         union {
                 struct vq_info_block s;
                 struct vq_info_block_legacy l;
@@ -423,7 +422,6 @@ static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
         struct virtio_ccw_device *vcdev = to_vc_device(vq->vdev);
         struct virtio_ccw_vq_info *info = vq->priv;
         unsigned long flags;
-        unsigned long size;
         int ret;
         unsigned int index = vq->index;
 
@@ -461,8 +459,6 @@ static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
                          ret, index);
 
         vring_del_virtqueue(vq);
-        size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
-        free_pages_exact(info->queue, size);
         kfree(info->info_block);
         kfree(info);
 }
@@ -494,8 +490,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
         int err;
         struct virtqueue *vq = NULL;
         struct virtio_ccw_vq_info *info;
-        unsigned long size = 0; /* silence the compiler */
+        u64 queue;
         unsigned long flags;
+        bool may_reduce;
 
         /* Allocate queue. */
         info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
@@ -516,33 +513,30 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
                 err = info->num;
                 goto out_err;
         }
-        size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
-        info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
-        if (info->queue == NULL) {
-                dev_warn(&vcdev->cdev->dev, "no queue\n");
-                err = -ENOMEM;
-                goto out_err;
-        }
+        may_reduce = vcdev->revision > 0;
+        vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
+                                    vdev, true, may_reduce, ctx,
+                                    virtio_ccw_kvm_notify, callback, name);
 
-        vq = vring_new_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN, vdev,
-                                 true, ctx, info->queue, virtio_ccw_kvm_notify,
-                                 callback, name);
         if (!vq) {
                 /* For now, we fail if we can't get the requested size. */
                 dev_warn(&vcdev->cdev->dev, "no vq\n");
                 err = -ENOMEM;
                 goto out_err;
         }
+        /* it may have been reduced */
+        info->num = virtqueue_get_vring_size(vq);
 
         /* Register it with the host. */
+        queue = virtqueue_get_desc_addr(vq);
         if (vcdev->revision == 0) {
-                info->info_block->l.queue = (__u64)info->queue;
+                info->info_block->l.queue = queue;
                 info->info_block->l.align = KVM_VIRTIO_CCW_RING_ALIGN;
                 info->info_block->l.index = i;
                 info->info_block->l.num = info->num;
                 ccw->count = sizeof(info->info_block->l);
         } else {
-                info->info_block->s.desc = (__u64)info->queue;
+                info->info_block->s.desc = queue;
                 info->info_block->s.index = i;
                 info->info_block->s.num = info->num;
                 info->info_block->s.avail = (__u64)virtqueue_get_avail(vq);
@@ -572,8 +566,6 @@ out_err:
         if (vq)
                 vring_del_virtqueue(vq);
         if (info) {
-                if (info->queue)
-                        free_pages_exact(info->queue, size);
                 kfree(info->info_block);
         }
         kfree(info);