s390/virtio-ccw: Fix setup_vq error handling.

virtio_ccw_setup_vq() failed to unwind correctly on errors. In
particular, it failed to delete the virtqueue on errors, leading to
list corruption when virtio_ccw_del_vqs() iterated over a virtqueue
that had not been added to the vcdev's list.

Fix this with redoing the error unwinding in virtio_ccw_setup_vq(),
using a single path for all errors.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 2edd94a..3217dfe 100644 (file)
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -244,9 +244,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 {
        struct virtio_ccw_device *vcdev = to_vc_device(vdev);
        int err;
-       struct virtqueue *vq;
+       struct virtqueue *vq = NULL;
        struct virtio_ccw_vq_info *info;
-       unsigned long size;
+       unsigned long size = 0; /* silence the compiler */
        unsigned long flags;
 
        /* Allocate queue. */
@@ -279,11 +279,8 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
                /* For now, we fail if we can't get the requested size. */
                dev_warn(&vcdev->cdev->dev, "no vq\n");
                err = -ENOMEM;
-               free_pages_exact(info->queue, size);
                goto out_err;
        }
-       info->vq = vq;
-       vq->priv = info;
 
        /* Register it with the host. */
        info->info_block->queue = (__u64)info->queue;
@@ -297,12 +294,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
        err = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_VQ | i);
        if (err) {
                dev_warn(&vcdev->cdev->dev, "SET_VQ failed\n");
-               free_pages_exact(info->queue, size);
-               info->vq = NULL;
-               vq->priv = NULL;
                goto out_err;
        }
 
+       info->vq = vq;
+       vq->priv = info;
+
        /* Save it to our list. */
        spin_lock_irqsave(&vcdev->lock, flags);
        list_add(&info->node, &vcdev->virtqueues);
@@ -311,8 +308,13 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
        return vq;
 
 out_err:
-       if (info)
+       if (vq)
+               vring_del_virtqueue(vq);
+       if (info) {
+               if (info->queue)
+                       free_pages_exact(info->queue, size);
                kfree(info->info_block);
+       }
        kfree(info);
        return ERR_PTR(err);
 }